legacycentral bbs

Is there away to test the ECU to see if it is dead? My engine is getting no spark from the coil, I tested the coil with an ohm meter and it is good, then I replaced the ignition relay and still no spark. I am thinking that I may have fried the ECU. Any way to test the old one before I get another one from the boneyard?

Well, there are some checks you can do (in no particular order):

Is the ECU getting power and ground? Check at its pins: http://www.graphics.cornell.edu/~v/ecupins/

Does the Check Engine light come on when you first turn the key to the "ON" position?

If you connect the green pair of connectors under the dash together when the key is in the "ON" position does it start to cycle the relays and solenoids?

If you have access to a Select Monitor you can also try seeing if the scan tool can communicate with the ECU.

I know that it is powered and grounded. The check engine light used to come on with the ignition and now it doesnt, when I connect the green plugs nothing cycles and when I turn the ignition on I cant hear the fuel pump prime. So it sounds like it is fried huh? If it is fried how do I make sure that I get the right ECU. I know I need to get it from a '90 Automatic but some of them say they are for thru 5/89, 6/89 only, from 7/89 thru 10/89 or from 11/89. Is there a number somewhere on the ECU that I can check?

Hmm... If it's getting power but the CEL doesn't come on and test mode doesn't do anything, that does sound like the ECU is fried. What happened that might have done it? They don't usually just up and die. I think you should try to find and rectify the problem before you just put in another ECU and risk the same thing happening again.

Are you in North America? If so, any ECU with the part number 22611 AA38x (the x can be any digit) will be a proper fit; those are the series of part numbers for 1990-1991 automatics. The last digit is a revision number but they're all interchangeable. That revision number is probably where those date ranges come from.

In fact, if you wish, you should also be able to use any 1992 non-turbo ECU (manual or automatic; they are the same); the part number is 22611 AA93x.

The part number is printed on a sticker on the lower face of the ECU as it sits mounted in the car, and starts with 22611. I don't know if you can read the sticker while the ECU is still in the car.

If you can't source one locally, PM me; I have a spare ECU from a 1990 non-turbo automatic.