Sensors that can cause turn over but no start

I'm wondering if someone knows all sensors that must be functional for the stage 2 MPI & Ignition to come on when trying to start a 996. I've swapped the ignition switch electronics and Crank position sensor. I know the Cam sensors could do this but I'm wondering about all sensors that could cause this. The ECU & Immobilizer have been sent to The ECU doctors and got a clean bill of health. I can turn on the stage 2 Fuel Injection systems with Durametric and hear the fuel pump & a few things in the back running, but when the key is turned it's not coming on. (Starter does & I appear to have spark) I've checked the fuses involved & relays (13 in the front)(1,2,7 in the back), plus the fact that I can turn it on with Durametric kind of rules out no power. I think all 4 O2 sensors may be bad but didn't know if the pre-cat ones might cause the ECU to not turn on Fuel & Ignition because it needs a reading to calculate the mix. Does anyone know if you unplug all 4 O2 sensors would the car still run with a default setting. To clarify, I don't hear the fuel pump at all when the key it turned to on & it does turn over but doesn't seem to even try to fire up. I don't hear fuel injection components coming on but I do get spark at the plugs. Starting fluid didn't fire up either. 1999 996 C2 Any thoughts welcome and appreciated.

Put a fuel pressure guage on the rail and let us know what the pressure is. U can rent the kit from most autoparts stores. U need fuel, air and spark for the engine to run. If u know u have spark then it must be fuel or air....if u have all 3 then its not timed correctly. The o2s have nothing to do when startng. The computer will go to a defualt value if unpluged and through a code.

Check to make sure you have not crossed up the bank 1 Cam Sensor and the Crank Sensor.......I have seen this a dozen times and it kicks everyones azz They are right next to each other and will plug in....even though they are color-coded black and white...it is not as obvious as it seems when they are dirty and happens a lot... When the engine is in the car it is a pain in the azz to test the wiring because these connectors are buried back next to the AOS...so it kicks some azz untill you finally get in there to test the wiring.. Since it won't start with starting fluid, that eliminates FUEL, ....so check these connectors NEXT...

Thanks for the O2S info, I�m sure there�s only residual pressure from running the pump via software. I have ran a long fuel line from the pressure side of the pump so I can see it pump when turned on with Durametric & confirm when trying to start no fuel is pumping, not that I just don�t hear it running.

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Thanks, I read about the connectors being swapped beforehand so was very careful to get it right when I did it. Bumper cover, heat shields & mufflers are off the car so it was easy to see and swap out.

Check to make sure you are getting 12v to the injectors, coils, MAF, Vario-cam solenoids, and change-over valves.... They should all power up when the key is turned ON...They get power through some relays and fuses....IF no power, check the fuses first...

Can someone with a 996 & Duramtric tell me what you see under real time values for Ignition Timing? My ECU is still not happy & won’t turn on the fuel injection when trying to start. My Durametric shows 78�, not sure if that’s advance but sure it shouldn’t be 78� either way, maybe timing is what the problem is… Thanks for any thoughts

Please show a picture of the screen that shows 78� . It Sounds very much like a (intake) temp value, though then you wouldn't have written � but F, I guess. I have no such picture myself but perhaps searching the pictures in the many durametric threads on here gets you the info you're looking for.

Yes, the temperature values are in Celsius. I will connect the Durametric today and post screenshots of what I�m seeing. Thanks.

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Durametric won�t report crank angle without engine running. The screen shows 78, that number has no real value concerning timing. when you try to start vehicle what reaction does your tachometer exhibit ?

Thanks. I don�t see the needle bumping. I have swapped out the crank position sensor though. I�m wondering if the flywheel is rusty or maybe even so rusty that the dual mass part is fused maybe it could cause this. Also I see spark on plug#3 when cranking, haven�t looked at other plugs. Seems to be ECU not sending ground to the fuel pump relay when cranking. But if I tell ECU to turn on the fuel pump it does it.

Ohm test the cps wires back to the dme to check for continuity. Its very weird that u r getting spark but do rpm jump at the dash. May have missed it but can u see rpm with the duremetric when cranking? Also have u put a fuel pressure gauge on the systen yet? Most autoparts stores rent them for free.

When you see spark, then ecu knows crank position, I.e the cps is working. No other way around it. Jump the fuel pump relay by connecting terminals 30 and 87 in the relay and see if the engine will then run. If not check if the injectors receive +12V when ignition is on (haven't re-read the thread to see if you've done that already). DMS rusted solid won't cause what you describe I am not sure if engine starts and runs in limp mode when either crank or camshaft position sensor fails. It needs both for sequential injection but with only one of the two signals batch injection would work. It is just a question whether this is implemented on the M96/DME 5.2.2 or 7.4

I have jumped the FP relay, it does come on but still no start. That has me thinking some critical sensor may not be working. The Durametrc seems useless to diag what may be failing. If I go to actual values/ RPMs to see if it shows RPMs while trying to crank it won�t even turn over. I was hoping it could show some realtime errors when it is turning over.

At the FP relay I have 12.4 volts on 30, when I turn key on I have voltage at 86, but no ground on 85 to activate the relay. But when I tell the DME to turn the pump on it does ground 85 and the pump runs. So I think wiring is fine but DME not happy about something & won�t send ground when trying to crank. Thanks again for suggestions. I will check injector voltage, been putting it off due to how difficult it is to reach them.

I would also consider going through the relays and bench test the fuel pump relay, the master relay, the ECu relay IIRC they are all the same part number. I use a socket from the autoparts store for the 5 pin bosche relay, I have the socket wired to a light bulb for the load. Makes it quick. These cars are getting older and the relays do age eventually.

Something else I thought of is that the Airbag control module has been swapped with same part# from a donor. I've seen posts saying it was swapped and worked fine and others saying it has to be reset / married to the car. Would that cause the DME to not let it start, or just throw a warning? Original got wet, wasn't seen by Durametric, new one is seen & error free according to Durametric.

Did your driver side floor get wet? Many evils come from that..

Yes, donor immobilizer as well, but entire set has been verified good by Specialized ECU Repair aka ECU Doctors.

you might go over the ECY connections and make sure the pins are all seated correctly in the male and female connections to the ecu.. One loose pin could be a heck of a gremlin.

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Yes, the x59's looked good, but I still cleaned them with Deoxit. I think I will revisit the connections between the front & rear harness in the step plate / door jams. They were both pretty bad. I repaired the broken ones & cleaned it up but it I'm thinking I may still have low or no voltage on something. Fuel pump relay and relays 1,2 and 7 in the back have all been confirmed good. (and getting near battery voltage at all 4 of these relays 12.4v) (this is after 1st cleanup to see what I was dealing with) All broken pins repaired, all green is gone but so is most of the plating)

Deoxit also makes a G-series spray called gold G5. Supposed to condition gold surfaces, enhance electrical connections. might help Did you ever get a chance to check for voltage at coils and injectors? In the run position the coils for example should have 12 volts if the relay is working.

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Thanks, no I haven't checked the injectors yet but will as soon as I have time. After I repair & clean or even re-connect anything I'm coating it with Stabilant 22a. I will check the coils also, hasn't been high on the list since I appear to have spark. I have a friend coming to visit this week, my plan is to recruit him to help me test stuff, should be easier with a helper.

Why Porschenstein? I dug her out of the graveyard and I'm trying to bring her back to life.

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I checked the coil voltage. Ignition on the whole time (3-4min), checked in order. Battery start 13.3v #1 12.8v #2 12.7v #3 12.6v #4 12.4v #5 12.4v #6 12.4v battery end 12.6v

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In your previous post looks like you swapped fuse panels. Was your car in a flood possibly? Anyways looks like you�ve replaced and cleaned a lot of wire connections. Alright seems like your coils have juice. Did you use the ground at the coil plug or just the engine metal? You may need to check ground points 10 and 11 unless you checked at coil end for ground. otherwise the DME is the component that tells the coil to fire. The reason I question the coil circuit is that you tried starting fluid and that didn�t help with ignition. Might be easiest to try again when your help shows.

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I have confirmed ground at GP10 & 11. When testing coils I grounded directly to the battery. I can re-test grounding at GP10 & 11 if that matters. I was just out checking relay voltage again, It seems all voltage at the involved relays is fine. Looking at relay2-1 MFI-DI, seems it closes and I do have 12.4v at pin 86 RE/BL, just as expected. But I'm not sure where to look beyond the relay on pin 86. It seems to interconnect with others at [26] on the diagram. Them goes to a few different places. Far right from [26] goes to X2/5 pin8 then to radiator fans. Center from [26] to Hot Film Air-Mass Meter. Center left from [26] to pin54 on ECU UB Switched (This seems like it may be it since this pin appears to trigger air/fuel components) Left / Center from [26] to X59/1. Is [26] just a reference point or is that an actual spot that I can find all these wires coming together & test? My main interest at this pint is ECU pin 54 UB Switched, according to ECU Doc's the ECU was installed in a 996 and works fine. I guess next spot to check voltage is ECU connector at pin 54? Any help understanding where all this RE/BL wire is going and where to check voltage is greatly appreciated. Yes, she was flooded in Hurricane Ian and I have cut many wires. But I am confident in my work on these wires and everything electrical that I test works fine. I can activate Fans, Air Pump, Windows, Locks, Lighting, everything basically through Durametric and they work. Outside of Durametric, chimes, lights, blinkers, radio, ac fan, windows, horn, again, everything electrical besides fuel & air management seems to work fine. Here's where I'm looking at [26], seems like 3 activated relays (pin86) converge and split from here.

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There is your problem !!!! Red/blue is the 12v power to just about every sensor on the engine, it has two big splices where 6-8 wires are all spliced together, the main power comes from the MFI/DI relay.. Since you have the 12v at the MAF but only 5.8v at the ISC, your issue will closer to the splice near the the ISC... MAF, ISC, both cam sensors, all change over valves, purge valve, ect all are powered by the red/blue and go through one of the two big splices... If it is a bad connection and not a "shorted wire" you could do a temporary jumper wire anywhere near the ISC, and see if she runs..... Then get down to the nitty gritty and trace the haness to pinpoint and repair the issue... QUOTE=Porschenstein;18991443] [/QUOTE]

Awesome thanks, I hope this is it, definitely seems to make sense... " two big splices where 6-8 wires are all spliced together " anyone know where this spot is to keep me from digging?

Okay this gets a little convoluted at least for me. term 86 at MFI relay gets power from fuse C1 through weld point 25. Main relay at DME pin27 grounds coil and term 87 feeds power to weld point 26. Pin 8 at X connector 59/1 receives that 12volts and feeds to weld point 9 which powers the idle speed control. DME pin 54 gets power from weld point 26 which in turn it uses to power the variocam solenoids. hope this is of some use�.

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The DME doesn't power the variocam solenoids, it "grounds" the solenoids to activate them.... BTW ; that brings up an old memory of a variocam solenoid that was causing a low voltage on the red/blue circuit due to a partially shorted solenoid ... Disconnect both variocam solenoids to see if the 12v power returns to normal..

Duh, never mind, assuming it's this. I was thinking lower in the car and got wet. Haven't opened it to look at the splice but this didn't get wet.

@ Porschetech3, I just noticed you said two splices, is the splice near the the ISC in the engine bay? I have 12.8v at this splice. Thanks

Yes the other big splice is in the engine bay in the engine harness, but before you go digging for it, disconnect the Variocam Solenoids. Jumpy's comment made me remember a case I had where one of the variocam solenoids was partially shorted causing low voltage on the red/blue circuit...

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Thanks, I�ll do that next. They probably did get wet.

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Both unplugged, no change here: No power to either vc solenoid with ignition on, but hoping maybe they only get power if they're activated?

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This exchange was posted on Rennlist site and sounds interesting and accurate.

Porschestien, looks like the vario cams get 12volts from weld point 9 as well as the idle speed positioner. You could take a gander at the X59/1 connector where pin 4 and pin 8 reside. Might still have iffy connection in connector. looks like pin 4 supplies power to injectors and coils if I�m not mistaken, which is entirely possible and I�m always open to criticism and or correction.

Thanks, I will definitely be looking at the x59�s and RE/BL circuit in the engine harness next.

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Yea that post only tells half the story with no conclusion... It also insinuates that the vario-cam solenoids gets power from the DME, but it does not....Vario-cam solenoids gets power straight from the battery through the MFI/DI relay and two splices and the x59/1 connector This is correct VVVVV ... The DME does not control the engine by controlling the power, it controls the "ground circuit" to the already powered components, ie. injectors , coils, solenoids, switches ect.. The only power the DME sends is a "5v reference voltage" to get feedback from hall sensors, rheostats, and variable resisters type sensors... All DME's, ECU's, EEC's, I have ever had the pleasure to troubleshoot work in this way, they are a big fast grounding device...

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Disconnect the purge valve, the change-over valve for the resonance flap, the change-over valve for SAI , also the change-over valve for Tiptronic if equipped,leave the vario-cam solenoids unplugged, then check to see if the 12v to red/blue at the ISC is returned to normal... If not then jump to mid-point at the x59/1 pin 8 to see if 12v is there...This should eliminate half the wiring as a possible .. Low voltage on the red/blue circuit will keep the injector relay from even turning on.....

I'm not really sure what's what as far as these, but here is what I looked at today... Valve or Pump in the fuel expansion / evap tank in the passenger fender well:

I think this is the other part of that fuel purge / recovery system in the rear:

Throttle Plate (Works when tested in Durametric):

change-over valve

Seems like the motor may have to come out to find the bad spot in RE/BL in the harness?

You're real close !! IF you have 12v at the purge valve and change-over valve, but not at the ICS the issue has to be between the ICS and splice #9. I don't remember exactly where splice #9 is but I think it is behind the A/C compressor..surely it will be between there and the x59 connector... I would not drop the engine, but that is just me...

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I find it strange to read 5.6V. I would have expected either ground/0V when the charcoal Canister was being purged (I.e. valve activated) when the measurement was taken or not give a reading, when the valve was not being activated.

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I find it strange to read 5.6V. I would have expected either ground/0V when the charcoal Canister was being purged (I.e. valve activated) when the measurement was taken or not give a reading, when the valve was not being activated as then that pin would not be pulled to ground through the ECU. Or am I missing something? Good job on measuring all terminals and documenting it nonetheless!

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Think about it like this:::: You have a 12v power wire and a control wire,.... when testing the plug if you have a "true ground/0v" on the control wire, when you plug in the connector the valve will actuate.........to deactivate.. the DME must undo the true ground,.. that leaves a floating ground or floating voltage that has no real potential/amperage capabilities..hence it can read just about any voltage but has no potential to do work/amperage, some transistors can pull to ground very well but can have residual floating voltage that causes no harm but can be very misleading if you don't test for amperage

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Thanks for the explanation! I'd thought along those lines with the 5.6V being typical for semiconductors but didn't know that it would show like this when not pulled to ground.

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So it looks like I had a couple components mixed up, good and bad. I'm pretty sure this is actually the Idle Positioner and voltage is good, traced back to x59/1 pin 8 as expected.

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And this is actually the Throttle Plate Angle, 5v is correct. Toned out to x59/2 pin 22. Then goes to the 5v supply from the DME on pin 53. Traced all the way to x2/5 pin 16 where it goes to Differential Pressure.

I have checked the fuel injectors now, 12.x volts. It seems I have correct power on everything I've checked. Today I've been checking the fuse box for about the third time, seems good on all fuses involved in engine management but I found one strange issue. On Fuse C3 going to the Alarm Module, I can reach ground on the feed side (Top). These two RE/BR wire supply power to the module. I have battery voltage on the supply side of C3 (Bottom). Also, The module seems to be working fine. Also interior lighting which goes out when the fuse is pulled. I would think if it was shorted to ground that the fuse would blow instantly?

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Can anyone confirm if the Airbag module has not been reset / activated it would cause the DME to not let the car run?

Not 100% but u have never seen an abs modual interfere with starting.

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Thanks, I was thinking if the donor 996 was in a crash, the Airbag module would probably shut off the fuel pump. But I don't know if that is a function handled by the Airbag module. Also you would think Durametric would show an error with the module.

Yars ago when the crank position sensor went bad on my car it would turn over, but the fuel supply would shut off. Once I replaced the CPS it ran again.

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Thanks, I already replaced it, no luck.

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Did you check for 12v power at the injectors, colis, MAF, change-over valves, purge valve ect.??

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Yes, thanks for all of your advice. Although I only checked injectors 3 & 6 since my hand fits enough to reach those two. I think my next tasks will be putting noids on 3 & 6 to see if they�re pulsing. Also to pull the seat back out an figure out why I can tone ground on C3 fuse. I also thought maybe I need an assistant to turn the key to see voltage on all that while the starter is running. Thanks again, really appreciate your help.

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OK, since you have 12v at all the injectors,coils,Maf, change-over valves, purge valve, ect, and the starter spins good, and you have good fuel pressure(?) and good compression (?) Then go back and triple check this..

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It was actually fuel injector 3 & 5 that I could get at, haven't checked the other 4. At this point I'm assuming one on each side is good so maybe all 6 have power. Not sure about fuel pressure, since the pump doesn't come on. Should I jump it or turn on via Durametric so the fuel pump runs and check pressure? Haven't bothered since the pump won't run without being forced. Can it detect low compression, and not turn on the fuel pump for that reason? I can check compression, but not sure how many rotations before stopping to look at the gauge? I will, but it'll be a quadruple check... and I do see plug 3 spark when turning over . Haven't checked all 6 for spark. Thanks again, really appreciate the help.

ECU cannot check for low compression. You crank until the needle on the compression tester no longer moves. Ideally you find a way to record the pressure achieved on the first compression stroke and count how many strokes pass until the pressure no longer increases. Do this for every cilinder. If you can, open the throttle body fully during all your measurements.

Ok, then lets back up even further to the BASICS Three most improtant things an engine needs to run.. 1 Compression 2 Fuel ( and air) 3 Spark More in depth things and engine may need to run 1 proper timing of spark 2 proper timing of valves ( this can also effect compression readings) 3 proper fuel So ; 1 Test compression on all cylinders, three compression strokes is enough to max out readings 2 Test fuel pressure with gauge ( a substitute fuel can be used as a test ie, starting fluid/propane/ just to see if the engine will run and verify that the other two necessary basics are OK ) 3. Test for healthy spark once every compression stroke on every coil... So go back and verify these three things to see which one is missing, because if they are all there, THE ENGINE WILL RUN ...

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I understand all that and will verify what I can, but at this point I know for sure the fuel pump isn't coming on. That's why it's my main focus at the moment. Since I can jump the relay and it comes on and I can put the relay back in and turn it on with Durametric, it appears that the pump, fuse, relay and wiring is all good for the pump. I have confirmed when the key is turned on, FP relay pin 86 gets 12+ v. So I want to determine why the DME isn't sending ground to pin 85 on the FP relay when the key is turned. Until the pump runs when the key is turned, nothing else matters, it's not going to run. Please don't take this as argumentative, I do appreciate all input, just explaining why the fuel pump is my main concern at the moment.

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It certainly sounds as though you have it narrowed down. If you bypass the DME to activate the pump does the car start and run?

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No, I�m thinking the DME is not activating any fuel/air components for some reason. Probably one or more bad wires that I haven�t found yet. Wishing the Durametric could show realtime log data from the DME to maybe give a clue as to what�s missing. I ordered a Foxwell NT530 yesterday, hoping it may see something the Durametric can�t see. I�ve read Durametric is limited on the gen 1 DME 5.2 cars. Currently removing plastic covers in the driver door sill so I can un-tape the harness. Haven�t looked for weld points in there, it was under water so maybe something in there burnt in half while grounded in water.

I would be inclined to check the subsystems that signal the dme to block engine run .Three come to mind- airbags -rollover -burglar alarm .Manny years ago a renlister had a no start issue that turned out to be the steering wheel was not installed and tripped the airbag fault. Since the dme checked out as good by ecu doctors and you can activate the fuel pump via durametric but can't activate with the key seems like dme has a no run condition set .Another question would be the key and imobilizer compatibility -don't know if ecu doctors checked that .

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ECU Docs did confirm that, I sent the key as well and they said they tested on bench and installed in a 996 & it ran. Plug & play they said. The no start due to Airbag module is a prime candidate since mine was toast. I was thinking if the donor module had deployed the bags maybe it can tell DME no start until it�s reset. Also seen some say it has to be married to the car by VIN. You would think Duramtric would report that though, it sees the Airbag module & claims it�s error free. I�ve seen Airbag module cloning services & am considering it just to rule it out. Hoping the Foxwell device does a better job of diagnosing than Duramtric. If anyone can confirm the Airbag module can create a No Start condition on the DME that would be great. I would definitely have it cloned or reprogrammed if mine is too far gone to clone.

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Pin 12 at dme is where airbag module connects -don't know characteristics when activated it's either ground or voltage .Quick call to ecu doctors might get an answer .

This is nice to know about, eBay

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Durametric didn't show this. Maybe the Airbag module not being coded to the car is a DME no start situation. Or possibly one of the sensors is bad, the door sensors where under water. So looking at this & knowing the DME is good, thinking the Airbag module needs to be coded & locked, or maybe get the old one cloned. Not sure what step 4 is saying though, should pin 33 tone to ground or not tone to ground but have zero voltage? If everything is unplugged why would it have voltage?... Pin 33: Maybe the donor Airbag module was in a crash & no start set until it's reset? Seems likely that a junk yard part had been in a wrecked car.

After speaking with two different prominent Indy's, here's what they said regarding using a used AB Module in a 996. - The VIN lock cannot be overwritten, not even by the dealer. If airbags are deployed or the module dies for any reason the only option is a new module from the dealer. They can program it and lock it to your VIN. I spoke with a dealer, $1800 for the module and $450 labor to program it. I also came across this: I'm about 95% sure the used module I bought had probably deployed the airbags so the fuel pump is shut via DME pin 12 (EKP Cutoff). I think a used one that hasn't deployed may run the car, but will have a permanent airbag warning light that will only go away if you get a new module from the dealer. I have also spoken to the guys at airbagsystems.com, they say they can move the chip over to a donor to get past the VIN lock. So, the plan is order another module from someone who claims the airbags have never deployed. Ordered today. Test to see if the fuel pump runs, then send to have my original chips(s) moved over to this new module that's never deployed the airbags.

AFAIK on a 996 the airbag control module does not prevent a future start after it has cut power to the fuel pump in a crash that involved airbags. Even in more modern vehicles where power is cut by means of a pyrotechnic fuse it suffices to replace said fuse without the need to change out the airbag controller. An airbag light can be turned off using durametric or piwis on the 996, that I know for sure. You've already ordered a replacement but I expect it isn't the cause of your no start situation. Not sure I fully understand what the locked VIN inside the airbag controller does but if it means it will not work in anything other than the vehicle it came out off, it seems to me you would need to swap over the chip before you can use it for further testing. Good luck nonetheless!

my bet is it will start .I suspect the vin is for accident tracking -probably some obscure gov regulation .

While looking at 5.2.2 ECU tuning info I found another blurb that makes me think I have found the issue with the fuel pump not running. From a Pelican forum regarding ECU tuning on 5.2.2

As far as avoiding having to pay a couple of grand to the dealer to replace an airbag module that has failed. I have determined it can be done, just not with any auto diagnostic equipment like PST2 or PIWIS. You have to have an EEPROM reader that is capable of reading and writing the actual binary(HEX) data on the chip itself. It's stored in EEPROM memory within the processor that is a Motorola 68HC11KA4 chip. XProg or UPA readers are reported to have the ability to read/write to this chip, so that's my plan. Connect directly to the chip and clear the crash data and change the VIN to match my car.

Wow! That's ambitious. Keep us updated! You might find yourself with a line of people clamoring for business...

Have you fed the fuel pump directly with ground and +12V to get it to run and did the engine then start and run? Worth a try in my opinion before going down this rabbit hole of airbag control unit re-programming of a removed chip, which might not even be necessary. ETA: Just tracked back this thread and read in post #71 that you've tried and it didn't run. I'm repeating myself and different from what you wrote in post #78: An airbag light can be extinguished using Durametric. Also: An airbag control unit is paired to the vehicle by programming its VIN into it after which it is locked. This is done so the ECU's coding is correct for said vehicle as one single part number is used for 993 too (see TBS linked below) and for different markets too (for instance early 996 in RoW had no side airbags nor did 996 GT3 club sport/M003 optioned cars). As such an airbag module with a 996 US vin is coded almost certainly correctly for your use case. Therefore I myself would concentrate on first making it run with a separate ground to the fuel pump and only then revisit the airbag ECU. https://members.rennlist.com/jandreas/911Grp6_4-98.pdf

Quotes source posts: 19058816, 19058816

I definitely appreciate all the feedback but would like to reiterate & clarify a couple of points. This thread isn't why won't the engine start, it's what component or set of components can tell the DME to disable the fuel pump. All evidence supports that there is no problem with the the fuel pump, wiring, fuses or relay and the DME is intentionally shutting down the fuel system. Bypassing this to run the engine doesn't really help determine the root problem. Also, even if I can get it to run, I can't shunt alerts regarding the Airbag or pull the bulb and say who cares, it runs. It has a salvage title and will have to pass a safety inspection to allow me to obtain a rebuilt title so this issue has to be corrected. I agree, any alarm can be cleared, it's when it keeps coming back and the diagnosis is you need a new Airbag controller, the only remedy is to pay the dealer for a new part and programming. BTW, the alarm I do have isn't on the Airbag controller, the alarm from the Foxwell with ID 16 Signal from Airbag is on the Immobilizer & the troubleshooting involves pin 33 on the immobilizer(pin 33 defined as "crash detection") The goal with this thread is to make the fuel pump run when the key is turned, I'll worry about starting the engine once the fuel system runs as expected. Thanks again for all of the suggestions.

Admire your tenacity .Rewriting vin # seems feasible .Clearing crash data and resetting seems a stretch without intimate knowledge of the software .I would assume that once the crash sensor is activated it sets off the code to shut down which is different from a normal airbag fault .

Quotes source posts: 19059545, 19059545, 19059545, 19059545

Thanks, full disclaimer, I've been a computer engineer for decades, not my first rodeo manipulating or flashing an EEPROM. It's simple really, the only hard part is the ability to read/write to the device It's only 512KB of data, almost fits on a single screen. Read a crashed one, read a clean one and compare the data. where the crashed one has data, the clean one will be all FF FF FF's or maybe all 00 00 00 00's. Then you know the address range that needs to be cleared. And always start by saving the original data so you can revert if needed. Correct, it changes the pulse being sent to the immobilizer and shuts fuel until no crash data is present. (from what I have read or been told, no first hand knowledge of this but I will know soon.)

The car WILL run even with an airbag module that is not "locked" to the car... If the airbag module is not locked it will flash the airbag light several times after starting... Once it is "locked"/" married" to the car it will not flash after starting, but cannot be unlocked from the car with conventional means or PIWIS ..( but of course a REAL hacker or programmer can do it) The airbag module does shut down the fuel pump during a crash, but I have had cars that came from the body shop after crash repair with the airbag module not locked and running... Normally it takes 3 crashes and the airbag module or other resettable components must be replaced.. Having worked on commision in Dealerships for 50 years I always use the most efficient paths to find the problem quickly . I though you were close to finding the problem with no power on the red/blue that powers up most all engine components, but you were mistaken on the circuit you were testing.. I can see you have your own methods of troubleshooting , and while it is not the most efficient, I think you are capable of getting to the solution eventually. A lot of times the most simple fixes can be the most difficult, and I hope the info I gave above will help you get there...

Quotes source post: 19059431

Thanks for your clarification which I fully understood. Wrt the quote in bold: I'm curious to hear how this is argued/explained as being so by design as opposed to coming to this conclusion based on 'heresy'. I am unsure whether you are of the understanding that the airbag controller must be replaced in your vehicle because it was designed to be by Porsche whenever a vehicle has been through the same (number of) accidents as yours or whether you have good reasons to come to the conclusion that not only the controller with the vehicle's VIN but also the 2nd hand replacement controller is faulty. Which is it? If the airbag light keeps coming back it could be other things like any of the electrical contacts in the belt receptacle, belt tensioner and airbags themselves that do not satisfy the spec (are intermittent or have too much resistance). Changing an airbag controller in such a case won't solve the problem. After an airbag has deployed the warning light can be extinguished and the fact that (at least) one airbag has been deployed is documented in a counter which durametric shows. I've read on other fora (no Porsche documentation given, unfortunately) that after 3 deployments the airbag controller must be replaced. It is the only reason for replacement I've come across as being inherent to the design of the airbag system. The part underlined is new information and would have me divert from focusing on the airbag module to the alarm/central locking modules under the seat seeing your car had been in a flood. The above is meant as food for thought not as criticism in any way and I'm sure either way will lead to ID'ing all signals and conditions that must be prevalent for the engine to start. Good luck!

Quotes source posts: 19059929, 19059935

Thanks, I needed someone who knows for sure to tell me I'm chasing ghosts. The dealer service department is who told me I wouldn't be able to use a used module, said not even they can unlock & re-lock to a different VIN. (but yes, everything I think I know about this is hearsay) Thank you both for taking time to try to help me figure this out. I did install the second used Airbag module yesterday, same problem, no fuel pump coming on. I also jumped the fuel pump relay & tried to start it again, no luck. And yes, all wiring under the seats was pretty bad, anything that was hot when flooded burned in two. I cut & replaced the seat connectors as well as 5 or 6 wires in the connections that marry the front/rear harnesses in the door sills.(x2/3, x2/4, x2/5) The immobilizer was flooded and toast, the one I'm running that was tested by ECU docs was cloned from my old one. I'm not seeing any errors on the immobilizer (cleared the one I posted earlier) so I'm wondering, wouldn't it show something wrong if say one of the wires wasn't making contact? The connector for it, #1 42 pin, was corroded but cleaned up pretty good so I didn't replace it. Plug #2 melted and has been cut off and replaced. Not that this helps solve anything, just an example of what I call "toast" :-)

Is the circuit between the pill reader and imbolizer known good

Quotes source post: 19060843

Yes, ECU doc�s replaced the circuit board in my FOB, programmed & tested it. The remote works on the doors and I think it wouldn�t even turn over if it wasn�t good.

forgot it disabled start circuit as well .If the foxwell and or the tach is not picking up rotation that might be a clue .I think the dme needs to know can position as well .The confounding part is that you have spark and starting fluid didn't light off .Perhaps its firing on the exhaust stroke-

Switching to the Alarm Module, I'm going to post what I'm seeing from the scanner to see if anything jumps out as not good. On input status, I can see the ones change that are just contacts, for instance, if I lock/unlock a door, I see the value change. The last one I'm really clueless about, but wondering if maybe something didn't come over on the clone and this needs a value?

I am sure you know this but key on fuel pump runs short 3 second burst runs again with engine rotation .

Quotes source posts: 19060954, 19060954, 19060954

I haven't tried this since I got the Foxwell, Durametric didn't work because by the time I got it loaded up and on the right screen it had been too long and wouldn't crank over without turning the key back to off then start. That disrupted connection to Durametric. I'll see if I can get the Foxwell on the correct screen and crank to see if RPMs show up. I don't see the needle bounce. I haven't even been able to reach the cam sensor plugs to check for voltage and clean the connectors. I'll re-visit that. I was surprised as well, at least a rumble of trying to start. I'll look a spark again today, it was a while back and I only pulled plug 3 and watched while my wife turned it over for me. #3 was definitely sparking as it turned over. Also, when I jump the fuel pump, nothing. I've been thinking maybe if the ECU knows it's not supplying fuel maybe it doesn't bother with pulsing injectors or caring about air.

Quotes source post: 19060996

Yes, it should prime with key on, so far that's my instant clue that's it's not working. This did make me think about it though. I've been assuming the ECU has it shut off since I can turn it on through the ECU menu with Foxwell or Durametric. I'm also assuming it controls the prime as well since the relay is activated by the ECU grounding the relay. Maybe someone knows if it should prime regardless, maybe it's before the ECU has even determined to shut off the fuel?...

Quotes source post: 19060954

I still had to turn the key back to off & start real quick but the Foxwell did show 0 then this while cranking. Seems high to be spinning on the starter.

Have no clue what that # means -should show 200 to 400 or so when cranking .I am not sure that this primes without engine rotating -saw a post on renntech that said it didn't .I don't know .The cps can be air gap sensitive in years past some folks on here have had issues with replacements and having to shim .Logic says get cps registering on foxwell and go from there .For diagnostic purposes it helps to use a auxillary start switch so you can run tests with key on .

Quotes source post: 19061110

I will put the original CPS back in and see what it shows, the new one was a cheap replacement since I didn't even know if it was the problem. Here's a couple of questions that I've been wondering about : I've been assuming the ECU has the fuel shut off since I can turn it on via scanner. Wouldn't the scanner show a fault indicating the ECU had it shut? Also, to hook up the remote starter switch, what's the best way to connect one? The starter seems unreachable, not sure if the start lock relay is also the starter relay and can connect to it.

jumper wire on start/lock relay for remote starter Don't know answer on ecu recording faults -do know that if tach needle ain't jumpin it' wont run .I would also test cps wires for both crank and cam from connectors back to dme pins .

Quotes source post: 19064234

Thanks

the fundamental question is: does fuel pump run without engine rotation .If no ecu is performing correctly .Without cps signal dme isn't active ..

Quotes source post: 19064234

Sorry but I want to clarify just to be safe. I wasn't sure if I should pull the start lock relay and jump 30 to 87? thought maybe that messes up RE/BL MFI relay on 86. Or leave the relay in and ground 85?

I just put a jumper on 87 and and applied 12 volts via a remote start switch

Quotes source post: 19064536

Makes sense now that I think about it, 30 would only have power if you turned the key. Thanks again.

Quotes source post: 19064543

Incorrect, unfortunately. (Terminal) 30 is battery terminal +12V , iow always live. It is Terminal 15 that only has power, after you turn the ignition on. So you'd connect 30 and 87 with a switched jumper

Quotes source post: 19064902

incorrect in this case -relay position 30 is only powered when key in start position

Quotes source post: 19064929

That appears to be the way mine is, I tried jumping 30 to 87.

I did apply power to 87 directly and ran the starter while watching the Foxwell and the Durametric. Foxwell showed 120 RPM jumped to 160 for a second then back to 120. (and strangely changed back to 2040 when I stopped it the first two tries, restarted the Foxwell and stayed at 120 the 3rd. time) Durametric showed 80 RPM. (maybe slowed down because it was the fourth test) I can tell it's turning a bit slow, I do keep a trickle on it, typical starting battery is 13.4. I also connected another battery to the jump point in the engine bay, still turns slow.

slow turning -grounds good ? What is battery voltage when cranking ?Less than 9 battery suspect.This probably will mean nothing but does foxwell /durametric show accelerator pedal movement ?

Are the o2 sensors disconnected ?

Quotes source post: 19065407

Almost all ground points have been checked and cleaned just to do it. Definitely 6 through 13, not sure about 14 though, thinking it’s the one near the top of the transmission housing. If 12 is the one by cylinder 6 in pass wheel well then yes. Voltage seems okay while cranking, I’ll check it again, also slave battery made no difference. Yes, I can see scanner actual values change on the throttle position when pressing the pedal.

Quotes source post: 19065470

I have tried with & without, scanners do show a value when I look at O2 sensor temp. Currently they are connected.

I am out of ideas. Compression test is a logical next step. Is this a manual transmission?

Quotes source post: 19065644

Yes, manual. I haven't worried about compression since I have no fuel yet, not just no prime or I'm not hearing it, I'm sure of it. I have ran fuel line from the top of the FP housing & turned on with scanner to drain the tank twice, I left it connected while turning over the engine and no fuel flowed. Thanks for all of your suggestions, I'll keep plugging away at it and post any progress.

I spot checked cylinder 3 over the weekend, for injector pulse, spark and compression. Compression is low, not sure it's low enough to cause no start and still thinking I have to figure out the no fuel issue. Pulse - yes Spark - yes Compression - 123 You Tube

Quotes source post: 19072468

Seems low,, Last 3.4 I've tested had 185 across the board. But probably not low enough to not at least stumble to a start with ruff idle maybe..? As I've started other type engines with 120psi no problem. What are the other 5 cylinder compression numbers..? Its important they are all similar. Did the engine ingest water..? If the battery isn't spinning up to speed that will cause a low reading on comp test...

Quotes source posts: 19072515, 19072515, 19072515, 19072515

That's what I was thinking, at least attempt to start or start and run like ****. I will check the others and post results. Yes, not submerged but the water came up the exhaust and flooded the exhaust ports. I cleaned them up as much as possible, could be sticking a bit and causing the low compression. It's spinning slow, 120 RPMs or so. Maybe also the valves sticking a bit since charge on the battery is good. Thanks for the input.

Quotes source post: 19072552

Do a leak down test.

more questions :what did old sparkplugs look like, spark test is with coil removed and attached to a grounded spark plug ,battery voltage when cranking .

I was too cryptic on the battery voltage .Had my car on a battery maintainer -starting became sluggish -voltage checked as good except when cranking it tanked .Battery tested at autoparts srore and confirmed not enough cranking amps .

Quotes source post: 19072677

The plugs weren't that bad, mostly black looking carbon and a bit moist. I cleaned them up and that's what's still in the car. I left it hanging in the coil pack, grounded by leaning on the header.

Quotes source post: 19072846

I did have it tested at Autozone, but didn't see the results, they just said it's good... I have been connecting a deep cycle marine battery to the jump port in the engine bay as well. Still turning slow.

Quotes source post: 19072997

I would still check the voltage when cranking just to rule out batteries should be 9.5 or better when cranking .Is the accessory belt connected ?There is a reason it's slow cranking it's a stretch but one of the pumps or the belt tensioner could be frozen .Was it in a fresh water or saltwater flood ?

Quotes source post: 19072552

This is very concerning... Just to be crystal clear, are you saying you've seen evidence of water flooding/intrusion into the exhaust ports of the heads..?

Quotes source post: 19073232

I haven't elaborated on how bad it was because I don't want all the "you're wasting your time comments". To clarify, I know this engine may never run. I'm trying to get to the point where it would run if it was good. In other words all systems seem to be go and the only reason it won't run is because it's bad. Why? Because I don't want to buy a used engine and have the same issue of fuel pump not running because I missed something in all of the wiring repairs. So the goal is, I find no issues that are preventing it from running other than the fact that this motor is bad, and then maybe buy a used engine. No question, the exhaust ports were full of salt water and debris. I cleaned it all out, removed almost all rust by making plates to bolt to the exhaust manifolds and pumped it full of Evaporust and let it sit for a few days. Then coated the exhaust valves with fogging oil and turned the engine over with no compression a few times to loosen the valves up. Until I did this the engine was seized up. Since it's almost Halloween, here is a scary video...

Mostly exhaust port footage but the last several pics are of the crank and one of the cams, inside the motor looks clean, sorry about all the F bombs in the videos. You Tube

Guess we know the root cause of turns over slow .Why not load it up with starting fluid and give it a go ? Recommend a face shield and other protective equipment .In fact better push it outside and use the remote starter the shrapnel could be significant .good luck ..... .

I think I'm going to pull the headers back off and smear assembly lube all over the valves, pull the plugs and spray fogging oil in the cylinders, turn it over quite a bit with no compression to see if I can loosen it up.

Salt water and aluminum is bad add evaporust and scale is more bad .Cylinders are probably past shot pistons worse .Seems like a lot of wasted motion to get fuel pump to run .It's a science project at this point -my starting fluid comments were made in jest .There could be salvageable parts from the engine that continued experimentation will render useless .

Quotes source post: 19074435

Thats what I thought after putting together all your posts... Interesting you choose to keep this minor point from us till now...lol Well, if you must, maybe try this old timer shade tree farm mechanic technique... In my younger more frugal days of barnyard finds, had some 'success (using this term very loosely) with filling motor to the top with kerosene and 1 gallon of marvel mystery oil, letting it soak for days/weeks. Also fill spark plug holes than reinstall plugs quickly to not lose any. At the least it will help with disassembly if you choose to try and selvage any good' (highly unlikely) parts..? Did get some of them running like this, not running good though, and in this context using running very loosely....

Quotes source post: 19074591

Because I never asked why the engine won't run, I figured that was probably the case when I got home with it and couldn't turn the engine with a socket on the crank pully. I started the thread to troubleshoot why the ECU won't turn on the fuel pump, because it can turn it on with a scanner, kind of eliminates FP wiring or FP relay so something is making the ECU decide to not run the fuel pump. I don't want to drop another 12k on a motor swap and still have no start because I haven't figured out the fuel pump issue.

Quotes source posts: 19064985, 19064929

I see what you mean. The relay position 30 designates that +12V Battery voltage is connected to it. On the wiring side you see that going to it is actually a wire coming from terminal 50, 'hot on start/during cranking. The two wires right of the starter switch are designated 30 and are, as you can see, always live, +12V battery voltage. These terminal designations like 15, 30, R(adio) and such are stamdardized in DIN:72552: https://en.m.wikipedia.org/wiki/DIN_72552

Quotes source post: 19074541

They're not great. I think some of it is smeared carbon from the fogging oil but they've seen better days. This is today, after I sprayed oil in it and cranked it over a couple of times. All the black greasy look is carbon with oil on it. My scope sucks, low res but better than nothing. You Tube

Looks like it may be bore scored already. I'd jump the FPR, button it back up and hit it with starting fluid and see if it runs.

Cylinder leak down test were really bad, 30% to 60% loss on all cylinders. Mostly from the exhaust valves but I could hear / see the leaking air from intake valves and oil filler tube as well. Now the tough decision to move forward with a used motor or send her back to the graveyard... Leaning towards the graveyard, already out 10K plus almost a year of labor. Too bad I didn't start with the engine, I was trying to will it into working out by repairing everything but the motor, fatal mistake.

Different perspective :The really tedious part of the job ( wiring) is done .Now it's pretty straightforward find a motor and bolt it in .I would drain the transmission oil to check for water intrusion -probably not but .....

Quotes source post: 19098550

Have you considered a swap, LS or 2.7t...? If the car body/suspension/interior/etc, is decent/good, why not swap in a cheap 2.7t or boneyard LS..? You seem like a pretty handy DIY type that would excel in a DIY swap. Be nice to have a 450hp 996.1

Quotes source post: 19100485

The main reason I'm hesitant to keep spending money is because it's a salvage title. Until it's repaired and passes inspection I can't register the car. I'm worried I'll have a ton of money in and for some reason I can't get a title, then I'm really screwed. Looking at a 2001 C4 as a replacement, just need to get 5-6K back out of this one first. I've definitely thought a lot about it, first choice would be get a Jake Raby street performance rebuild on this one, else maybe a used motor. I like the Renegade Hybrid LS idea but it's just a different power curve and probably the most money of any choice. I really like the feel of the H6 that belongs in the car. I like the 2.7t idea but that would probably require ECU and wiring changes. Actually I think I would fail inspection with anything other than original engine from same year 996 donor. Of course if it's the 3.4 they don't even need to know I swapped the engine.

The leak test numbers are indeed not very inspiring but if it were mine, I'd get the engine running and drive it (where you can legally do so without registration) in order to give piston rings and valves a chance to seat as well as they can given the engine has sat for so long. Might not improve much but you don't have anything to lose by doing so.

1999 996 Cabriolet crank not start Fuel pump not prime but works and I jump it when I try to start. Replaced relay CPS new and replaced. no Tach Bounce Ignition switch fine New Battery. Checked all grounds check every single fuse in car (good) No Spark. fuel only goes when I jump relay. (pressure at rail) swapped relays DME. only thing I am down to send out immobilizer ECU and Keys (new batteries) even thou keys work and locks work Anything I should check? Advice? I removed the ECU and immobilizer and keys and under seat to Fedex out to Specialized ECU repair HELP

Quotes source post: 19288952

I did that, it�s good to rule out but the engine won�t turn over if the immobilizer is bad. I plan to rent a PIWIS 3 very soon and will post what it finds. I�m pretty sure it will be a fuel system related sensor that�s failed or no/low voltage on a pin that the ECU needs to run the engine. My engine is probably bad but I can�t say for sure until the fuel pump issues are resolved. I�m still not convinced the SRS Module isn�t the issue.

I'm not sure what I'm looking at here, DME / Actual Values / Drive Links Curious if anyone with real PIWIS experience knows if these are things preventing the DME from allowing the car to run? Thanks,

Those are use for doing emission test and letting you know it ready to take and have smog test done, all the parameters would say ready. This does not prevent you from starting the vehicle. have a look under Fault Codes and list what your seeing.

There are no errors present, here is the VAL from the PIWIS. I marked what I found concerning. It doesn't seem to be a physical issue, the fuel pump and wiring are fine. For whatever reason the DME will not turn on the fuel pump, I think it's in a no start state, and still suspect the used SRS module. I tried to unlock it and lock it to my car in engineering mode, don't think it can be done. (as the dealer already said) Vehicle Analysis Log attached in PDF format

Why not try to rebuild this engine since you got yourself so deep. into it. Also I might have missed the response since it is such a long thread, did you end up cloning the airbag module? I am working on a similar project, feel free to DM

I wasn�t able to clone it, had the chips specs and eeprom programmer but couldn�t read it. I also moved the chip from mine to a donor but it wasn�t seen by the PIWIS when installed. I�ve determined the lock on the module appears to be model not VIN, I told the PIWIS to lock it and it briefly shows Model 996 before it said it�s already locked. I took it to a prominent Indy in Atl a few days ago, they couldn�t get it going. Their analysis was the wiring harness is too far gone and must be replaced. The CAN bus is very sensitive to resistance and this harnesses was flooded in saltwater for several days or even weeks possibly. I�m going to try to do a more thorough repair on the harness or replace it.

I guess I was more lucky, I got mine started within like one year, however, I replaced: ecu, immobilizer, various relays, some latches, I am still finding all kind of electrical issues, AC control was dead, radio is gone. Alternator was not charging, however with a jumper wire to keep the fuel pump running mine started right up - unlike yours mine was turning nicely by hand. My airbag module is corroded pretty good so now it is completely taken out. I saw some listings on ebay of people cloning it, I have yet to try that - the reason I am mentioning this is that mine also refuses to send commands to the fuel pump relay.… While I was writing this I decided to used my scanner to send commands to the relay … somehow it seems to have jiggled the relay back? either that or it got stuck on or something .. like keeping it on once I manually actuated it? For the most part my harness seems ok, it is mostly the connectors/terminals that suffered but they seem to behave pretty good after some cleaning. I did try with ECU cloning and that worked marvelously( I saved some money that way - it ended up being much less than what Ecu Docs quoted me) - I still had to send it to them for the Immo marriage. Here is some alternator turbo noise. You Tube And the first start You Tube

I know it sucks to read through an entire thread and then it ends abruptly with no conclusion. Long story short, after almost 3 years, I gave up. To all those that told me it was a very bad idea to buy a flooded 911, you were correct. I sold it to CogsCogs Porsche graveyard that is close by. Joe is a great guy with a lot of used Porsche parts, and a Porsche transmission expert. He pulled the drivetrain, and the car is currently on eBay. My 2004 C2 arrived this past Wednesday, it�s an awesome car. Really nice condition with 80K miles on it.