19 captured repliesDiscussion pagination complete · Source accounts, not a confirmed diagnosis
THIS DISCUSSION / SOURCE-DERIVED OVERVIEW
Discussion summary
YOUR RESEARCHStarving for fuel on cold start
Reported or suspected cause
still present
Reported cause
No successful repair reported for this finding.
1
Identified cause
0
Suspected cause
0
Reported fixes
Read evidence and context
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Discussions that report identifying a cause
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Reported cause
May also want to try NO key cycling to reproduce the problem to make sure the problem is still present.
Leading evidence: 'still present' (1 discussions report identifying this cause; no attributable repair resolution). Across 1 matching discussions, the most frequently mentioned possible cause is 'still present' (1 discussions; 1 report identifying it and 0 suggest it). The most frequently discussed action is 'Check fuel pressure' (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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Discussions that performed work without a confirmed outcome
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Performed · outcome unconfirmed · Original poster
I was able to feather the throttle to where it usually stalls but it revved up and ran normally.
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
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Performed · outcome unconfirmed · Original poster
I cycled the key on and off slowly three times listening for the fuel pump to stop priming each time and the car started and ran normally solving the cold start issue.
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
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Suspected cause
- Once you're confident the problem is due to lack of fuel at start up, you can invest more time and effort to troubleshoot in that direction e.g., check fuel pressure and flow (from the fuel rail) and also see if the pressure drops too quickly after the engine shuts off.
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that contain suggestions
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Suggestion
If we can prove that theory, you can continue with checking the fuel pressure with engine ON and OFF and see if it's holding pressure.
Discussions that performed work without a confirmed outcome
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Performed · outcome unconfirmed · Original poster
I cycled the key on and off slowly three times listening for the fuel pump to stop priming each time and the car started and ran normally solving the cold start issue.
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Suspected cause
- Once you're confident the problem is due to lack of fuel at start up, you can invest more time and effort to troubleshoot in that direction e.g., check fuel pressure and flow (from the fuel rail) and also see if the pressure drops too quickly after the engine shuts off.
Counts describe captured discussions, not unique people or a diagnosis. Author identities are not reliably stored. Exact duplicate evidence is counted once across matching discussions; one discussion counts at most once per action/state. Multiple repairs reported together remain a combination. Suggestions and failed attempts do not establish a fix. Matches cover whole discussions and can include related faults, model variants and incomplete threads.
19 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.
Rennlist: 1 discussions
0 evidence records excluded for query context · 0 excluded by outcome qualification · 0 adjusted by outcome qualification.
2 acknowledgements have no verified action link; they do not establish a repair result.
Outcome without a verified action link
I finally got a chance to try this today but no change.
'03 911 C2 3.8L. 23K, First cold start after sitting for a few days car stumbles and stalls. Ignition has been on long enough to check oil level. Starts and runs fine on second attempt. Can be avoided by gas pedal once to the floor (like setting the choke back in the day). Car runs great cold and warm after started. Any advise would be appreciated.
An egas recalibration is an easy first step to try.
Turn car on but don't start the engine. Keep your foot off the accelerator pedal. Wait for 60 seconds and then turn car off for 10 seconds. You should hear some whirring clicking sounds from the engine. Then start the car as normal.
I finally got a chance to try this today but no change. Ignition on for 60 seconds then off for 10 and then start. I did not hear any whirring or clicking sounds. Car Started but stumbled badly and stalled then started right up and ran fine. Are there any other steps that I missed?
Fairly certain that your car has e-gas, so, do the e-gas calibration routine in a quiet place, like a garage, and open the engine lid to enhance the ability to hear the whirring clicking noise. The calibration routine is as stated. If you do not hear the whirring clicking sounds, check your fuses. I have a 99 so I don't have the fuse block diagram for an 03. The fuse diagram for your car is inside the fuse box lid. What I'm trying to say is - the calibration routine should work and you should hear the sound. If not, something is wrong.
My 2002 used to do EXACTLY this occasionally. On cold start, first time you would start it the car would stumble...and die immediately if you touched the gas. 2nd try, it would start just fine. Never happened cold. I did exactly what you do, on cold start up, I would start it up with gas pedal 1/2 way down. Didn't see any codes.
Thanks guys! I tried this again today and did hear the egas calibration take place. Unfortunately it did not help, stumbled on startup and was running at very low RPM's although did not stall but smelled like it was running very rich. I was able to feather the throttle to where it usually stalls but it revved up and ran normally. All this happened in a matter of 6 or 7 seconds. I am thinking that I will just pump the gas once before cold starts (when I do this it starts normally) going forward. Is this going to hurt anything?
Can you try this? Before cranking the engine, cycle the key between off and on a few times (with a few seconds in between) so you hear the fuel priming multiple times. I wonder if the engine doesn't have enough fuel.
Thanks Ahsai, that's exactly what it feels like (engine starving for fuel). I will try that but it will be the weekend before I am back in town to report results. Are you saying to do this before every cold start or just try it to see if it makes a difference?
Yea, do it every cold start for now and see if that makes a difference. It may give us more clues. Since the pump only primes for ~1s every time you turn the key and that may not be enough if somehow the fuel line is bleeding off pressure. If we can prove that theory, you can continue with checking the fuel pressure with engine ON and OFF and see if it's holding pressure.
03' or MkII uses a returnless fuel system so it doesn't have the traditional fuel regulator on the fuel rail. Instead, it has a check valve and regulates the pressure withim the fuel pump unit.
Another thing I can think of is intake air leak. OP, you may want to check the oil filler tube for cracks. Also, it may help if you can read the fuel trims like RKAT ( fuel trim at ilde) which will also indicate any intake air leak.
Ahsia,
I cycled the key on and off slowly three times listening for the fuel pump to stop priming each time and the car started and ran normally solving the cold start issue. Oil filler tube does not have any visible cracks. Don't know how to read the fuel trims. Any thoughts?
That's good. To read fuel trims, you need Durametric or any Porsche scanner.
A few more points I can think of:
- You may want to try a few more times to make sure key cycling fixing the issue was not just a coincidence. May also want to try NO key cycling to reproduce the problem to make sure the problem is still present.
- Once you're confident the problem is due to lack of fuel at start up, you can invest more time and effort to troubleshoot in that direction e.g., check fuel pressure and flow (from the fuel rail) and also see if the pressure drops too quickly after the engine shuts off. The fuel trim should be able to tell you if you have a leaky injector or the loss of pressure is in the fuel tank side (e.g., fuel pump internal check valve or leaky internal hoses inside the fuel tank).
Any news on this. I am having a similar issue. I'm thinking it is a fuel pressure issue for me or should I say check valve issue as my has issues of starting after not driving it for days to weeks on end.
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