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-   -   3.2 cold run problem ????? (http://forums.pelicanparts.com/porsche-911-technical-forum/1167215-3-2-cold-run-problem.html)

hermanator 09-19-2024 10:02 AM

3.2 cold run problem ?????
 
I rebuilt my 3.2 over the winter and it now has 1200 miles on it and was running fine.
Last week I was going to town and the radio station went fuzzy so I pulled over
to try and re-tune. Car was idling and when I went to take off she started sputtering
and bucking. Kept going to town and she started running fine again. Next morning
going to town she started sputtering and bucking again. After 3-4 miles she smooths
out again and runs fine. So I changed out the fuel filter and drove quickly and ran
fine. Next morning same thing, after 3-4 miles she runs fine again. Okay so changed
the plugs because my jet ski did this and plugs cured her. No luck with the car. So I
am confused on fuel or electrical problem. Have not changed the DME yet but am
running out of ideas. Anyone want to try and steer me in the right direction.
Only clue I can give is when this first started I had not put the air cleaner cover
back on after filter change. Cover on now but makes same symptoms.
Possible injector dirty? How to check?

Tks in advance... Herman

PeteKz 09-19-2024 01:55 PM

Start with basics: Compression, fuel, spark. Neither the fuel filter nor spark plugs will cause these symptoms, so congrats, you now have extra parts.

Does it run well at full throttle and high RPM?

Try spraying starting fluid in the intake when it is misfiring. If that improves the problem, then you have spark and are missing fuel, otherwise, you are most likely missing spark.

Since it's a 3.2., presumably it is a Carerra with Motronic (put that in your problem description). DME is a likely failure item.

hermanator 09-20-2024 03:24 PM

PeteKz: Changed out DME Runs great at high rpm and full throttle after 3-4 miles.
Only seems to act up with load and lower rpm. I think you recommended me to
Dick Elerud who did the heads for me. Thanks for that. Changed out DME and still
same symptoms. Almost like someone pushing kill button every couple seconds.
May have to call Dick and pick his brain. Tks again.

911obgyn 09-21-2024 03:09 PM

Check battery voltage and grounds several on engine and trans ground strap. Also ground on body by battery.

PeteKz 09-22-2024 02:39 PM

If it suddenly cuts out and restarts, like pushing a kill button, then I suspect an ignition fault. Since you already replaced the DME, As 911obgyn recommends, check the ground points in the engine bay, and anywhere else you can find them, ground straps, etc. Actually loosen, wiggle, and retighten them.

When did you last adjust the valves? Can you run a compression or leakdown test?

Yes, I did recommend Dick Elverud. Glad you got to work with him.


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