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YOUR RESEARCHMy new 99 just died in Denver. Help please
Reported or suspected cause
crank sensor
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Reported cause
That happened to my 2000 a couple of years ago, it was the crank sensor.
Leading evidence: 'crank sensor' (1 discussions report identifying this cause; no attributable repair resolution). Across 1 matching discussions, the most frequently mentioned possible cause is 'crank sensor' (1 discussions; 1 report identifying it and 0 suggest it). The most frequently discussed action is 'Check fuses' (1 discussions). For that action, 0 discussions report a resolution and 0 report an unsuccessful attempt. No action has an explicit, attributable resolution report under the current rules. These are forum reports and suggestions, not a confirmed diagnosis.
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Performed · outcome unconfirmed
The canister is always filled by the return from the regulator.
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Performed · outcome unconfirmed
After she sat for a few hrs, came back and started right up, drove home, looked on the web and ordered CPS and installed a few days later.
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Hey, she just died on me and won't start. Sitting in idle as I was about to leave a store. Turns over, full tank of gas.
I let it sit for a few minutes. Try again. It cranks and cranks, sputters and dies.
Any ideas?
I checked all the relevant fuses. All are ok. I don't have a Durametric.
Fuel pump sounds like a good guess. Any way to tell?
Ugh. This sucks. I don't want to be trapped in Denver till Monday.
I know your car does not have a HPFP as that is 2009 or newer. Not sure what else to check. Probably start looking for an Indy or a dealer to tow to so you can get it in first thing Monday. Possibly a auto store would have a ODBII scanner they will let you borrow or someone on this form lives in Dever and you can borrow theirs.
OP has �Crank No Start� condition. Cause is either no fuel delivery or no ignition. His post is confusing though - if by 99 he means 1999 model year then he�s in a 996, therefore no HPFP. OP you need to confirm what you�ve got.
When you're cranking it to try and start it, does the tach needle bounce up and down with the engine rotation or does it just sit on the zero. If it just sits there, it's your crankshaft position sensor. If it bounces up and down, it's either fuel or spark, as mentioned, and in that case likely fuel.
When you cycle the key before you get to the starting/cranking position, do you hear the pump buzzing?
OP, it's doubtful that you can fix your car where it sits, seeing as you're away from home. If you can hear the fuel pump run with key in position 2 that might help rule out fuel delivery issue. There is also a relay for the fuel pump, but I don't know where it's located on the 996. For the ignition part the only single point of failure I can think of is the
crankshaft position sensor
. If that's failed the DME doesn't know when to fire the
spark plugs
. You're probably forced into having it taken to a shop for repair. Let us know what the problem and fix were please.
Ok, I left it in Denver at Arvada German Garage in Arvada, CO, rented a car and drove home. Before I left, I did go back to it to test out the suggestions from @
Petza914 but I apparently had left a light on in the car and had no way to jump start it so I was unable to do what you suggested. I don't think I was going to be able to fix it anyway.
I'll post later when I hear from them. Thanks for all the suggestions. Sorry for the confusing post title. It is a new (to me) 99.
Argh! How'd I make that mistake? I must have fat fingered the link click since I made the post from my phone. Can anyone move this thread to the right location?
UPDATE: I heard from the shop. They said the fuel pump isn't sending fuel. They have ordered a new fuel pump that should be in tomorrow. I don't know this shop but they were well-reviewed in Google. It did appear that there were mostly BMW and MB cars in there though. I'm wondering how much experience they have with Porsches. The car is 20 years old but only 70k miles. What are your thoughts on the fuel pump being the actual point of failure?
Well, I guess you'll know soon enough.
Other than the 09 and newer DFI cars, and their high-pressure fuel pumps, I'm not aware of many fuel pump issues on here, but anything can fail at any time, so who knows.
Electric fuel pump in a port fuel injection engine is mounted in-tank, and is cooled by the fuel there. For max longevity of the new pump keep ample amount (say 1/4 or better) of fuel in the tank. For comparison, my wife's '07 Mercedes C230 had similar fuel pump failure at 70k miles two years ago. I'd say your failure is not unreasonable given age of the car. Shop doing your repair should have recommended a fuel filter change also. I'd insist on that as a precaution - or DIY it as soon as you can.
If they have no faults for the Crank Position Sensor (common) etc, then it must be a full mechanical failure such as the fuel pump. They just need to be sure that the pump is receiving a signal to fire, ie voltage and ground.
Unfortunately, all you can do is trust their diagnosis at this point, especially if they have more experience with these cars than 99% of the people in forums.
UPDATE: Arvada German Garage replaced the fuel pump and that got me back up and running. I drove her home yesterday just fine.
Today, though, after a trip to a few stores (honey-do list) I parked her in front of the house. I just now went to put her in the driveway to wash her and I'm back to where she won't start. This is the same thing! She cranks strong but won't start. Before I parked her, while I was out running errands, I noticed she was idling a little rough and I felt I had to give her some throttle to keep her from stalling at idle. Once she was going, no issues, not even when stopped at the light.
Could it be the fuel filter? Did I just replace a fuel pump that may not have been the problem?
Since you drove it home from Denver to Salt Lake you can rule out the fuel pump. Call Arvada and ask them for advice. If it were me I’d replace the fuel filter - especially since car is new to you and you haven’t mentioned having any previous maintenance history. If you do replace the filter have a look at the date stamp on old one. That may tell you a lot. Cutting open the old one for a look-see is tedious but is also instructive.
How long did the car sit before you went to start it? You should determine if this is a warm start issue or an any engine temp start issue. After sitting overnight does it start right up?
With the info provided, likely culprits (that I would have put far ahead of a bad fuel pump) are:
-crank position sensor
-ignition switch
-evap check valve (there are two)
I am assuming the shop read the codes. If they only replaced the fuel pump, I am curious which codes it had when they read them. You may want to see which codes it is throwing now.
I just replace:
TPS - Throttle position sensor
CPS - Crank position sensor
MAF/MAP - Air flow and air presser sensors
Cam position sensors (If equipped)
One every day or so for a week, just to make sure nothing is DOA...
as a set every 80k or so on my cars,, keep the known working parts
on the garage shelf for emergencies YMMV...
I talked to the shop and they had no codes reported. I just ran the Durametric and also found no relevant codes. He suggested the next place I should look into are the fuel tank vent valve and the fuel pump relay.
I assume if it was any of the sensors that have been mentioned that I'd have some codes to suggest their failure?
I just had a fairly similar issue over the summer. When the engineer got hot enough, the CPS sorted out and the engine died. It wouldn't start until it cooled down. It's about $100 and an easy fix.
Our Crank Position Sensor (CPS) fault was accompanied by a P0335 code. Reset code and it would come back, so CPS and P0335 seem to be linked together and apparently is not your problem.
On another vehicle we had an intermittent no start crank and crank we are stuck. An Angel appeared with a can of engine starting fluid and fires right up we're going home. Then fuel pump replaced and intermittent no start never happen again. You might try a few shots of starting fluid to help determine if you still have a fuel system or ignition problem. Not too much can wash oil from cylinder walls.
Thanks again to that Angel.
Not necessarily. I sensor that has completely failed, yes. But for a sensor that is failing, it may not malfunction until the engine is heat soaked which is why I asked the questions above. With answers to those questions we can further help diagnose your issue.
In each case, if I'm remembering correctly, each time was while the car was warm but not hot. I had parked it and either gone inside my house or a store for between 20 minutes and an hour.
The bad crimps on the Y cable have a failure mode where the car either slow cranks and no-cranks when it's warm, but not hot. If the car cranks strong but won't fire, that's a different issue than the bad cable, like a Crank Position Sensor.
So the only time you've started it cold (and it fired right up) was when you picked it up after the "repair?" Engine bay temps are easily 150+ degrees even an hour after it's been shut down. So to be clear, the only time you've experienced a no start issue is when the engine is warm, but it starts right up just fine when dead cold?
There are several different directions you can take here, you've obviously already experienced what can happen when someone incorrectly diagnoses an issue.... you pay them to replace a part that doesn't fix your car, no bueno. Based on the info you've provided, it could most definitely be a dying CPS. But it could also be an evap vent valve. Just need to understand exactly what you're experiencing and when.
I just tried to reproduce the no start conditions by running the car until it was at normal operating temperature and shutting it down. I returned to it 20 minutes later and it starts just fine. With the vent valve, I'd expect to have issues filling the tank and/or check engine light coming on. I'm not ready to rule it out, but it is lower on my list than the crank position sensor. I've ordered one and will replace it as soon as I can. I've also ordered a fuel filter to rule that out and give me a good reason to inspect the existing one. I'm hoping to find that it is not the original.
This is nonsense, nothing more than internet myth. If the pump has to be submerged in fuel to keep it cool then the tank would have been designed and built that way. The fuel running through the pump what keeps it cool and not being in fuel.
Not really. I bought a new fuel filter and crank position sensor but haven't had time to install them. She hasn't had any issues since the one time she wouldn't start when I got her home... but I work at home and don't drive much. I'll post up when I get the new parts installed. I'm actually hoping it will happen again now that I know to look at the tachometer when cranking it.
I should let this go but i cant. Modern in tank fuel pump assemblies are designed to keep the pump submered at all times. The canister that the pump is mounted in is designed to hold the fuel that is blead off the regulator. U will notice that the return line dumps directly into the canister. If u have ever pulled the pump assembly the canister is always full reguardless of the fuel level. U may think that its fuel so when the tank is low it can draw fuel but the inlet to the pump is under the canister.
I will also add as an avid off roader that has run in the dessert and the rocks with multiple different fuel system i can say from experience internal and external non fuel cooled pumps do not last. Ford used external pumps in a ton of trucks and mustangs and when we tried to use them they had a high failure rate. In the ultra4 series the guys would run 4-5 pumps in parallel to get though the 260miles king of the hammers race.
All areospace external pumps are built with a wet motor design. The fuel is blead off internally to both cool and lubricate the pump. These are the pumps we have moved to for realiabilty. Current automotive internal and external pumps r not designed this way mosty because of cost.
Getting back to the thread im betting on the pump or the in tank tube connection as a few of these have failed recently.
What you guys use for racing has nothing to do with the pumps in the 996 or any other in tank pump in a street driven car. Porsche would not deign a pump that can easily fail while under warranty. The 996 is not known for fuel pump failures. Just because Ford screwed up something once or twice doesn't mean that this design of a pump is a problem. Almost all cars in the last 20+ years have pumps like the 996 and the failure rate is extremely low. All these cars were driven by average people that do not think that the tank can't be below 1/4 or else their pumps will fail. They just get in and drive, light comes on and they at some point they refill. If these pumps would fail from being run above the fuel line then there would be a public uproar a long time ago. But this isn't happening. The prediction doesn't meet the reality therefore, the theory is wrong.
Pull your pump assemble. As u will see the pump is in a canister. The canister is always filled by the return from the regulator. It doesnt matter how much fuel u have in the tank. If the pump is pulling fuel it is keeping the canister full of fuel which is keeping the pump cool. This design is widely used throughout the industry to keep cost down by not needing to make a"wet" pump.
My point is that if the pumps r not submerged or internally cooled by fuel they fail.
Actually, I think the Crankshaft Position Sensor picks up the crank position every time it rotates. So, when trying to start the engine, the tack needle should jump a little as the crankshaft rotates. If it just sits and 0 and doesn't move at all, I think it's an indication of a bad CPS. I keep forgetting to look at my tach when starting my car to validate this.
I checked that on an air-cooled 3.2 today and it did not appear to move before the engine fired. And the sensor is new. It could be that in wet-engines the tach is energized earlier.
I plan to wait till it happens again before I replace the CPS so I can check the tach and see if that test is a thing on this car... but winter is fast arriving here in the mountains and I may fix it so I don't get stranded. That said, both times it failed was a warm start condition and I can probably consider myself to be in a warm place if I've stopped anywhere on purpose.
I just replaced the CPS in my 99 996C2 earlier this year. Went to a Dr appt, came out an hour later...no start. After she sat for a few hrs, came back and started right up, drove home, looked on the web and ordered CPS and installed a few days later.
No problems since.
I put a new fuel filter in it when I bought it in Feb 2018..in the C2 it is under the car btw.
Yeah, the filter was in the same place in my previous Porsche, a Boxster. I had just changed that one. The C4 filter is in the engine bay but looks as much of a hassle to get to as it was squeezing it between the coolant runners on the Boxster. Could certainly be worse though.
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