1988 Chevy Cavalier Quits running when the alternator regul

93 COBRA

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1988 CHEVROLET CAVALIER

Electrical problem
1988 Chevy Cavalier 4 cyl Front Wheel Drive Automatic 64K miles

the car starts and runs has a fast idle at start up hot or cold,(with the alternator unpluged) but corrects itself until its put into gear then it goes up more than normal, the service engine soon lamp is on and it won't scan, when the alt. gets pluged in and the voltage regulator kicks in it stalls the engine, also if a remote battery charger is connected to the battery and put above 20A it stalls the engine,
Things that has been replaced was the alternator 3 times, ignition switch, ignition module, ECM 2 times with remans. starter solinoid,battery?,fuel pump felay,ECM relay. wirring harness grounds to the ECM and body have been ohm's tested and pass,(toned).
Used a timming light to check ignition when the regulator is pluged in OK and used the t/light to watch the injector pulse when the regulator is pluged in also and it appears the fuel injector shuts down but the fuel pump don't and also the pump has been hot wired for the test from its prime harness
HELP
93 Cobra

7 Replies

JDL

MECHANIC
16,098 POSTS

Hello, just a thought, if the reg connector is a 4 wire, leave everything plugged in, pull the gage fuse, Start the vehicle, any difference? Pulling the fuse is just for testing, not driving around.

What kind of scanner were you using? Does it show live engine data? Disconnecting the battery cable for a few seconds may let the computer reset. The computer controls the ground side of the check engine lite, if the terminal pin at the computer is a constant ground, it shouldn't be.

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Friday, May 1st, 2009 AT 12:27 PM

93 COBRA

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5 POSTS

Thanks for your quick responce, and to answer your questions,
The regulator harness at the alt. Is a 3 wire connector and I did forget to mention that I had removed the gage fuse and made the car run, I have also removed the instrament cluster and chased for an open in the printed circut and found none, also ran the car with the fuel gage removed thinking somehow it may be related but nothing,
I have also bypassed the neutral switch thinking it may have something to do with the ECM. But it don't change anything. I somewhat remember that it quits running with the instrament cluster unplugged which I don't know if it should or not
Thanks
93 Cobra

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Friday, May 1st, 2009 AT 2:32 PM

93 COBRA

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Have you guys given up or stumped with this problem?

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Thursday, May 7th, 2009 AT 6:36 AM

JDL

MECHANIC
16,098 POSTS

Hi, I asked you what kind of scanner you were using? Does it show live engine data?

I asked if the terminal at the computer for the check engine lite ground, is a constant ground? You may have more than one problem.

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Thursday, May 7th, 2009 AT 6:59 AM

93 COBRA

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If I disconnect the black connector which has terminal B-22 for the SES lamp it goes out so I would venture to say it isnot always grounded, as for my scanner it is, AutoXray 6000 which does not comunicate with the ECM at this point. It has to do a basic scan before it will let you view live data which is very limited on this older of an auto.
The owner of the car went to (per him) Home Depo and shut it off, when he came back out and started it, the car would shut off after starting and its been like that ever sense that time. This is a strange one to me, never seen the problem and hope I never do again. If you can fix this you will get a donation.
Thanks