Can you please help me troubleshoot a Chevy Cavalier?


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Old 12-28-08, 09:17 PM
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Can you please help me troubleshoot a Chevy Cavalier?

Hi, I was asked to look at a '91 Chevy Cavalier RS today. Is has the 3.1 liter v6 engine. It ran fine when I drove it home, but when my wife started it to move it, the car died as it was idling. No indication of a poor running engine, it just stopped like she turned the car off.
Fuel pressure is 43 PSI when the fuel pump comes on, spark is a nice healthy bluish white color, oil pressure goes up to about 40ish when the engine is cranked, the tachometer registers a few hundred rpm while cranking, and each of the three coils ohm out about the same.
I'm not getting an injector pulse. I put a stethoscope to the one injector I can get too, and listened to it while the car is turned over. I plan on measuring voltage to the injector wires with the ignition key on, and TPS voltage. What else can I check?
 
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Old 12-28-08, 09:20 PM
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Oh, and I checked the crank sensor and found a crack, so I replaced that. I also noticed someone had disconnected the the oil pressure sending unit, which I reconnected.
 
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Old 12-28-08, 09:44 PM
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not sure about the cavi but i did have a grand am that the wire harness to the coils would get a bad connection dont know if it helps but hey its worth a shot
 
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Old 12-29-08, 04:38 PM
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You may want to check the timing belt/chain to make sure it didn't jump or break.Usually when it breaks the car will turn over quicker then normal but will not fire
 
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Old 12-29-08, 07:42 PM
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Methinks we're a tad ahead of ourselves.
FIRST are there any codes??? and if so which??
You can eliminate spark and engine problems with a short squirt of starting fluid........If she starts and runs off the ether, you'll know for sure it's a fuel problem
I'd test the injectors with a noid light....If it flashes while you crank the injector is getting some kinda pulse. I know on the 3.1 that's kinda a bear as the plugs for the injectors are almost all under the upper plenum
A scan tool would be useful......If injector pulse is in fact the issue, check for CAM sensor activity while cranking
Bon ChanceBeer 4U2
 
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Old 01-06-09, 08:08 AM
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There were no codes. I traced it to no injector signal, and found 2 bad injectors. One was at 6 ohms, and one was at 0 ohms. I replaced those and it fired right up. These injectors seem to be hooked up in series. If one goes bad, the injector signal is cut.
 
 

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