replaced ECM unit 4 times. .

[Guest]

My 1989 Reatta (has touchscreen) has had to have 4 ECM units. . no one (dealer) can't say why. . just keeps replacing them. Dealer says this shouldn't be happening so often? Help. . any ideas about what to do? Also, console lights flicker on,off. .annoying but not critical. . when this happens, the dash lights get stronger, weaker. . .car has 99,000 miles.

[padgett]

Insufficient data. <P>First: how do you know the ECMs were really bad ? Second: if they were, something else must be causing the problem.<P>Given the history of flickering lights, I would look for bad grounds causing voltage surges first). <P>Do you live under a power line ?<p>[ 01-11-2002: Message edited by: padgett ]

[Guest EDBS0]

agree on the ground problem. Poor grounds take out more electronics than almost anything. Robert

[bigrog]

I'm assumming by "dash lights" you mean the vacuum flourescent display lights(i.e., speedo display) which would suggest a problem with the 48 volt supply from the power supply module. If the central power supply module were to leak voltage from the 48 volt VF supply circuit to the 12 volt ecm supply circuit, I would expect to see dimming VF display and a very short lived ecm. <P> Just a quick thought on a possible relation between the two symptoms. A good suggestion as stated is to clean the power and ground junctions near the battery. Any control module will malfuntion with improper voltage, and may be damaged. Also, clean the ground junction at the ignition module mounting bracket, as this is a common area for trouble.<P> What are your failure symptoms? What failure condition does the ecm replacement correct? Also, what brand ecm is used? ACdelco or aftermarket? I would expect ACdelco from a dealer, and from experience would use nothing but in this application.<p>[ 01-12-2002: Message edited by: bigrog ]

[Guest]

Along with the checks on the ECM grounds, check the grounds on every part of the ignition system. Also use a good voltmeter to check the voltage with the battery fully charged and the engine at 2000 RPM. It should be around 14 Volts and certainly not over 15 Volts. You might also consider having a shop put an O Scope on the output of your alternator. Leaky output diodes can put a large AC componant on the electrical system, which will fry the on board electronics.