I have a 1993 Buick Century 3300 wagon. It belongs to my sister in law, who after my brother dying 2 years ago has left me with a "Single Woman and her Car", the mechanics dread of dreads, lol. 6 weeks ago it started stalling once a week, usually upon climbing to the top of a grade like a freeway on ramp. Hence I changed the fuel filter. As time went on, it would stall for no reason. It went to once a day, then to several times a day. I've changed the injectors, wires, plugs. Bought a fuel tester and checked out the pressures for the pump and the rail vacuum thingy. All is perfect.
I switched from fuel to electrical in my quest...
I have run the tests according to the article at: ICM test
I have a new crank sensor, fuel pump relay, TPS as well. The MAF checks out on the voltage and tap tests.
My ICM plug has some wires that are not used and have rubber nipples sticking out to mark that the terminal is not in use. (Marked by blue font)
I'm not seeing a Cam Pos. sensor, the car has no tach, etc. Having less wires does not throw me because I know a 3.3 is not a V8 Bonneville engine.
The only difference in the color code is the G position, what would be a yellow wire is really a dark blue with white stripe. But it goes to the same pin on the crank sensor. Just for fun, I did a continuity test on all 4 CPS wires and got a beep.
The 3rd & 4th tests check the pulse voltage from the CPS.
The third test is wire G. I did get the 6.5v to zero volt alternating signal. So the 18X CKP test checked out.
Here'* where I'm stuck...
One thing I noticed is the instructions seem to have a contradictory element. On the 4th test, 3X CPK signal test on the H wire, it says you should see 5 or 6 volt to zero volt alternating signal pulse as you rotate the crank. I do; 6.5v also.
But if the answer was yes it says the ICM is bad and to replace it. That is confusing to me. It says that I SHOULD see 5-6V'* then says it means the ICM is bad. You can only have yes or no and both answers require changing a "bad" thing. So after you change the "bad" thing, wouldn't you still get a yes or no answer?
My question is, do I change the ICM if I am seeing the pulse signal? I would think the test should result exactly as the 18X test.
Me thinks there is a typo. I'm in a quandary over it. I need this car out of my driveway. lol
The car still starts, runs for 3-30 seconds and shuts down. I can't get it to the end of the driveway :/
Oh, and I went to a DIY junk yard and bought a used ECU with exact numbers and letters on the paper label. I mean there was not one letter or number difference. It was from the identical year car w/3300 V6, save it was a sedan not a wagon. When I cranked the motor, the engine stalled the moment I let go of the key like an old ballast resistor gone bad. I reinstalled the old computer and we're back to ground zero with my stalling symptoms of 3-30 seconds running, then kaput! I would love to get the car to a mechanic to have it tested. I would like to finish all the tests I can do myself before forking out money I really don't have to have a shop scan it. I've already got $400 into this problem.
Thank you for your help