2000 996 C2 won't start after replacing variocam actuators

Ocean blue metallic 2000 porsche 996 Cabriolet. 155000 miles. I was getting 1325 and 1341 cel . So variocam for both sides... so I took things apart to find out that mechanic the previous owner had replace the actuators put them on the wrong banks. I followed the instructions in the manual and varafied the timing before I put everything back together. While I had the engine out I replaced the camshaft position sensors, did some clutch work. I put the engine back in the car and it would turn over but won't start. So I got on here and read a million pages.. First I replaced the crank position sensor. Still cranks but wont start. Tach does not move more than maybe a 8th of a inch at first while cranking. Put a fuel pressure gauge on the rail and its producing 55 psi. My simple code reader showed pending codes of 1397 and 343. So I pulled the engine back out and went through all the wiring on the harness. Checked all the sensor wires for continuity. Changed the coils because I noticed some small cracks and replaced the spark plugs. The old ones had gas on them so its getting fuel. Also replaced the knock sensors and the coolant temp sensor and the troublesome Y cable on the starter and voltage regulator on the alternator since I had the engine out again. I even tried putting the old cam position sensors back on just in case new ones were bad. Put the engine back in last night. Still cranks but won't start. It backfired once during crank. Put a code reader on and it shows pending codes for 1397 and 343.. cam position sensor codes . I have a durametric coming in the mail tomorrow but I'm just looking for advice on what to try. . I'm not a mechanic just a guy who loves cars and tries to learn and do everything myself. Car was running and driving before i started all this. The previous owner had the ims replaced right before I purchased the car and they replaced the variocam actuators while they were in there because the pads were shot. Unfortunately the work was done in Texas, where I purchased the car and I live in Missouri.

So it's getting fuel, but no spark? Can you roll the windows down? Turn signals work? Radio turns on? All ground wires to the engine hooked up properly? Where has your car been sitting while this work was being done? Damp area?

Check that the bank 1 cam sensor and the crank sensor wiring connectors are not swapped !!!! I have seen this happen SEVERAL times and is a PITA to figure out. If you look closely the connectors are color coded to identify which goes to what, but when things are dirty and in the car it is hard to tell, and they will indeed plug in WRONG..

Thank you so much for the responses. Yes the radio comes on and the windows roll down and I've opened up the top so I can get to the dme . I've done all the work in my garage at my house, it's not damp. I went through harnes when I had the engine out the last time. It appears all the grounds are in good shape. There's just 2 ground locations were they connect to the block. Near each cam position sensors right? Thank you for the suggestion on switching the connectors but the cam sensor is plugged into the right plug. I tracked down the wires for all the cam sensor and crank sensor wires when I was going through the harnes. I'm hoping the durametric will help me see something I've been missing... it should be here tomorrow.

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OK, but the last forum member said the same thing, and didn't trust what I said. or double/triple check. He went on to even by-passing wiring , hooking up lab scopes ect. in the harness before he admitted it was just the switched connectors

I will double check it for sure. Thank you.

I verified the crank position sensor is plugged into the correct plug. Like you said, its color coded. I triple checked it to make sure. Durametric is showing p343 and 1397. When I turn the car over it cranks a couple times then backfires once and then just cranks with no start. I'm at a loss. Might drop the engine again and take the engine back apart to see if I screwed something up with the timing when I put everything back together.

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Well that sucks.. You can check exhaust cam timing without removing the engine. The intake cam timing is done by counting links when installing, but you already know that...

Thank you for your responses Porschetech3 The backfire when I try to start and then just cranking without starting, and the dual cam sensor codes just seems to point to something way off in the timing doesn't it? I followed the instructions in the manual but I am not a mechanic and this is my first attempt at any camshaft work... I pulled the cam plugs last time I had the engine out and the the timing appeared to be right but you know how it goes... now I'm second guessing everything.... it's getting fuel, I mean the backfire must be the unburned fuel in the plugs when I first crank it over. So it seems to me like it's getting spark at first coupe cranks , causing the backfire, then no spark?

Just for the heck of it, try unplugging the MAFS and try starting it.

Thanks for the suggestion, but I tried unplugging the MAF. I saw the suggestion on one of the 400 posts I've read through since I started this...

"I replaced the camshaft position sensors,..." P0343 is an OBD -II generic code for a voltage problem with the camshaft position sensor. P1397 Camshaft Position Sensor 2 - Signal Implausible, Short to Ground, Short to B+ Potential causes: - No power supply. - Short circuit to B+ - Short circuit to ground. - CMP sensor faulty Since you are getting P1397 and P0343....could it be that the "new sensor" is bad?......I have purchased "new" parts that come defective out of the box...........my 2c I just re-read your first post...noticed that you swapped the old sensors back and still the same issue.....this definitely is a stumper...however, there is a "test" for the sensors, and would still suspect them............the wiring is the next suspect https://www.google.com/search?client...FytMPzIif8AU32

Will it start cam position sensors unplugged, only with crank sensor? It should...if not, either your crank sensor or cam timing is bad.

Just a thought and apologies if I'm teaching you to suck eggs but did you rotate the crank 360 after timing the first bank before timing the second bank , I've seen that before both banks timed in without turning the crank in between can create what you have, might be worth a check if your clutching straws?

I think you got the cam timing wrong on the two banks.

I'm going take the cam covers off and check the timing on both sides. Like the suggestions have said, I think it has to be the timing is not right. I had to remove both banks camshaft assemblies when I had it all apart since the entire assemblies were put on the wrong banks by the mechanic who screwed all this up in the first place. So I'm thinking maybe I did something wrong while reassembling. I followed the manual but not I'm second guessing everything I did so it's best i go back in and figure it out. The 101 instructions and the manual instructions are pretty good but having to do both sides at the same time I'm thinking i could have missed something. . I'm definitely learning a lot from this whole experience... its intimidating for sure but when I get it all figured out I'm sure it will be worth it ....

Fingers crossed!

Is it possible for the camshafts to be installed and the sprocket on the end that goes to the ims chain to be off a tooth. If so how do I verify that the sprockets are right?

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What I've heard the manuals are very vague. You might find it helpful to purchase Jake Raby M9X engine assembly video series. He goes over 5 chain camshaft timing.

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Took the words right out of my mouth! Volume 5

First thing I would do before you rip into the engine is just pop the green plugs out where you put the timing tool in , it's the opposite side to where the scavenge pump is. Get the engine at TDC then try to fit the timing tool , you should see that the slotted end of the cam will line up horizontal with the line where the cam cover meets the head. Now this is where you can check if you got it right , basically only one bank at a time should line up at any one time , basically get in TDC , check left bank , if it doesn't line up , rotate crank 360, now it lines up yes , that's good, now check the other bank, if it's NOT lined up that's good , it shouldn't , now turn the crank 360 and the other bank should line up and the first bank shouldn't do, if you can set the crank at TDC then the timing tool fits both banks without any crank rotation you need to alter it , you will have to take out a scavenge pump off one of the heads and unbolt the timing pulley , probably remove chain tensioner first for this bank, then rotate the crank carefully by 360 and bolt the pilot back on , obviously with the timing tool attached on this bank , I would then carefully hand crank the crank pulley a few times checking each bank timing to make sure the tool goes on nicely , then that should do it , only problem I can see is if you can't get the timing pulley of wether it will turn on the end of the cam with the bolts out as when you turn the crank 360 the chain and pulley will turn as the chain is attached to the ims which is attached to the crank, just be careful it doesn't bind as you turn the crank go slow and keep checking , if it's not good , pull the cover and remove the pulley off the cam while you do the crank rotation , hope you got that!! Good luck, I've got a copy of the porsche technician manual which helped me , the timing instructions are quite good, I rebuilt my engine a few years ago before Jake had his vids out, might be worth a buy , I'm tempted myself!

The videos would be great. Really expensive... but great. Those of you who suggested I had the timing wrong were right. I swear I thought I had rotated the crank 360 before I did bank 2 but apparently I did not. I kept checking the timing and the mark's were where I thought they were supposed to be. But I completely misunderstood that you check the timing on one bank and then rotate the crank 360 and check the timing on the other bank.... guess I'm just dense and even though ibe read a million pages of forums and instructions..i had it wrong. I took both cam covers off and removed the camshafts, then went through the entire procedure to install both banks, rotatating the cams 360 between installing bank 1 and bank 2 this time. But now i can only manually rotate the crank about halfway around, so roughtly 180�.. and it stops.. wont go further.... so I had to walk away from it for the night. .

I've got the porsche 996 tech manual, details the timing procedure , also refers to the notch position on the other end of the cam next to the scavenge, you use it to check orientation, it helps it become less confusing, if the engine has locked up tight don't force it something is wrong , probably a valve touching a piston !! Are you sure it's not compression?? If it feels harder but bouncy it's compression if it's like a brick wall solid it's valves on pistons , stop and re check , pm me your email and I'll share you the manual on my google drive so you can print it off and use that ??

thank you Noz1974. I pm'd you my email address. I have the "911 carrera (996) technical manual". It says WorkshopManuals.co.uk at the top. I have some of the spark plugs removed so its got to be something I did wrong again not compression.. Since I had both banks of the engine apart at the same time is it possible that I have cylinder 4 at tdc instead of cylinder 1 when I started the process. How do I know if the engine is at tdc for cylinder 1 or cylinder 4 if i have both banks camshaft assemblies removed? Also when removing the ims chain sprocket from the camshaft it seems like its possible for the sprocket to "skip teeth" so how do I know if the ims sprocket chain is right? Sorry for the million questions. When i started all this i felt pretty confident in what i was attempting but now going on 2 weeks of takimg apart and reassembling and in and out with the engine... I'm second guessing everything ...

If you are starting with both cams removed, you know cylinder one is at tdc when the crank is locked on the tdc slot through the pulley and then you have installed the cam so that the timing tool fits in the slot at the end of the cam (piston 1 is at the top of its rotation and locking cam in position so that the timing tool fits ensures that the cam's rotation sequence is TDC for cylinder 1). Once set, unlock the bank 1 cam, rotate the crank 360 and repeat for bank 2. I know you've been told this a couple of times but the workshop manuals are not great about timing procedures. After as much time as you have spent taking things apart and putting them back together, making an investment in the videos would seem to be a no brainer to me. Why not buy the entire CD set and then once you are done, sell the CD set with a $100 discount or something.

If I were doing this car, I would remove the engine from the car, put it on an engine stand, and start the cam timing from scratch. The way it is now, you have gone down too many paths of unknowns... it's impossible to guess what is going on. Get back to a known good place and start there. For me, it's engine on the stand, cam shafts OFF the car, chain hanging down from the case. Cam timing on Porsche 911 has always been: doing TDC on bank 1, then turn 360 degrees to TDC on bank 2 for cam timing.

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Or just buy the chapter on on cam timing...I watched it yesterday and the tips and tricks ("silver billets") Jake highlights are a big bonus!

Well there is 3 videos actually listed for the 5 chain timing. I haven't watched the 5 chain so I'm not sure what's covered in each video. I would think the marketability of a full set of the dvd's wouldn't require a substantial discount to a buyer vs. buying new once you have used them for your purpose. Or just keep trying to do it trial and error.

Is it normal to get P1397 and P0343 codes when the timing is off?.....those codes are specific to the sensor being bad or the connection being bad. aren't specific codes for timing off?.....pardon my ignorance.... P0010 "A" Camshaft Position Actuator Circuit (Bank 1) P0011 "A" Camshaft Position - Timing Over-Advanced or System Performance (Bank 1) P0012 "A" Camshaft Position - Timing Over-Retarded (Bank 1) P0013 "B" Camshaft Position - Actuator Circuit (Bank 1) P0014 "B" Camshaft Position - Timing Over-Advanced or System Performance (Bank 1) P0015 "B" Camshaft Position -Timing Over-Retarded (Bank 1) P0016 Crankshaft Position - Camshaft Position Correlation (Bank 1 Sensor A) P0017 Crankshaft Position - Camshaft Position Correlation (Bank 1 Sensor B) P0018 Crankshaft Position - Camshaft Position Correlation (Bank 2 Sensor A) P0019 Crankshaft Position - Camshaft Position Correlation (Bank 2 Sensor B) P0020 "A" Camshaft Position Actuator Circuit (Bank 2) P0021 "A" Camshaft Position - Timing Over-Advanced or System Performance (Bank 2) P0022 "A" Camshaft Position - Timing Over-Retarded (Bank 2) P0023 "B" Camshaft Position - Actuator Circuit (Bank 2) P0024 "B" Camshaft Position - Timing Over-Advanced or System Performance (Bank 2) P0025 "B" Camshaft Position - Timing Over-Retarded (Bank 2)

To the OP, maybe this older topic will be helpful: https://rennlist.com/forums/996-foru...-question.html

Removed the engine completely again because I was getting resistance when I turned the crank by hand. pulled the cams for both banks and the still couldn't rotate the crank completely. I have a broken exhaust valve. So I'll be removing the heads and will need to have the valves replaced. I've never attempted a valve job so I'll probably have to take the heads to a a machine shop to have them done. I had the timing wrong because I didn't rotate the crank in between setting cams in the two banks. I must have broken the valve when I was rotating the crank at some point because the break is fresh. car has 156000 miles and since the mechanic who did the IMS and actuator rebuild originally, screwed up the banks and had the entire camshaft bank and actuators swapped, its possible it did some harm to the valves anyway and they should be reworked. I'm learning a lot about these engines for sure.. I'll post updates when I get my heads done.. thank you for the helpful posts.

I admire your tenacity in solving this problem. It will get done. Good luck.

How did this turn out?

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lol..not good I think ??

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Looks like it didn�t�

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I hate when a good thread just dies off.