Price on ECM?

[Guest Kimber]

Could the mechanic be correct? Says my problem is due to a bad voltage regulator in the ECM and that it cannot be serviced. Do I let him get me a "rebuilt" one, or am I better off getting one from one of the forum members? Prices? You are welcome to submit private emails.

see my threads: "Is it going to blow up?" and "Thermostat?Temperature Coolant Sensor". Problem is a very fast idle on a 1990 with about 90,000 miles(starts at 1600 and climbs to over 2000). Engine does not know when it is warm. ECM diagnostics read E016C (high voltage). Battery is new. Alternator was tested off the car and tested good. Alternator was tested on the car (disconnected alternator and regulator, car still idling over 2000 rpm). Everyone has tested for a bad ground. Could the mechanic be correct, or do I bring the car home?

[Guest Buick Mike]

I recently had the ECM replaced due to the old one holding the #3 injector wide open at all times. I paid $160 for the part. (I'm sure that's not cheap, but the shop is honest and stands behind their work so I willingly pay their high prices.) I want to say the part was new, but if there is no such thing as a new ECM for the Reatta, then it wasn't.

Mike

[padgett]

Is possible but didn't you say that a meter measured 18v at the battery with the engine running ?

" battery read 12.5 volts with car off, 18 - 20 volts with car on, back down to 12 volts with car on and alternator/regulator disconnected. " - I assume that was a seperate meter.

Only the alterator could do that. OTOH if that is what the dash readout said and not a seperate meter then I would run that test first.

That said 18-20v to the ECM could definately fry things particularly the interal voltage reading which is probably in front of the voltage regulator, but it could confuse antything.

Now the ECM cannot affect the alternator in any way that I can think of, is just not in the charging control circuit. Further, if it is going bananas on the car, is a lot better test than any AZ device. I'd replace it and the ECM at the same time.

[2seater]

Padgett is absolutely right, the ECM does not control the alternator. The BCM does provide the power to start the alternator, but the regulator is inside the alternator itself, and does the voltage regulation.

[Guest Greg Ross]

Last year paid about $90./ exchange for an ECM for my '88 at AutoZone, supposedly a rebuilt. It lasted less then a year.

[Guest Kimber]

IT IS FIXED! See "Is it going to blow up?". The mechanic did not have a clue. When he said that the voltage regulator in the ECM was bad, and had me buy a new one, he was actually testing the BCM and argued with me when I questioned him. I took the car away from him, and fixed it myself with help from the forum members. I replaced the alternator, which corrected the high voltage, but still had the "Service Engine Soon" so replaced the ECM since I had it anyway. That did it. All is good. The BCM, which he said had a bad voltage regulator, was fine. Thanks to all!

FYI, a remanufactured ECM would have run me $228 from GM, so I got one from Jim Finn. Thanks Jim!

[padgett]

Wish I could afford to open a shop (and get to be home every night) but still at the dog food retirement stage. Need to at least make it to hamburger.