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87 Buick Electra 3.8 Misfire?
Hello, I'm a first time Buick owner and first time poster.
I am experiencing a few problems with this project vehicle's engine: Initially when I got ahold of the vehicle there was a misfire on cylinder #1. Initially I believed this issue was the coil pack, but it turned out it was a ignition module. However, this yielded weak spark opposed to no spark. After this, I checked what codes the vehicle was reporting, and yielded a code 42. At this time the motor was bucking + misfiring. Before, it was simply misfiring. Further inspection of the engine found the crank position sensor was hit by the pickup. I took the dampener off and put the pickup back within the tolerances so the CPS would be within the correct cap on each pickup. (Which leads to the question of how the pickup got out of spec to begin with. . .) The engine is still running poorly and cutting off if the motor is left to idle. The engine is fine in terms of compression. I have a few questions: could this be the ECU, and also, does anyone have a wiring diagram for the 3.8 ECU -> ICM in order to test this? (Also, what is the color of the bypass wire?) Any input would be greatly appreciated. Thanks, Kurt |
Half solution! :)
Okay. Turns out the ICM was indeed bad, and I replaced the coil pack for good measure. The crank sensor was replaced, and the cam sensor as well. The primary issue of misfire is gone, as a full tuneup has been done. After this a high idle was noticed - At first I was assuming this was the ECM compensating for motor problems. This was actually a bad TPS. The fuel pump was weak, so it was replaced and the sending unit was cleaned. Idle is fine, but now it takes FOREVER to crank - up to 10 seconds? Fuel pressure is still 10 pounds under what it should be -- at 30 instead of 40 - 43 - A lean code is still being thrown. (And a high voltage, and low voltage reading codes from the computer)
Perhaps the regulator? :P I will say this is a fantastic ride from the 80's, all told. Kurt |
Regulator bad. wasn't holding pressure to the fuel rail.
Still runs lean at idle, with backfiring into the intake if the car it put into WOT If it doesn't cut off, the car stumbles horribly into higher speeds. |
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These cars had a real problem with the mass air flow sensors. Cant buy new and the ones from a JY are usually bad.
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