I'm almost certain that the ECU is dying. I got a couple of codes off it while it was working, and then the engine quit. I'm getting a constant 12V off the ECU test terminal now.

Has anyone gotten a rebuilt ECU off eBay? They run about $189, which is considerably cheaper than the $250 advertised price from http://www.autocomputersupply.com/.

Well, after much dismay, I've found what is causing the ECU malfunction. I took apart the unit, and after fiddling around with it, I saw a black crud on the wiring harness connectors.

ANTS!!



Check out the upper left hand solders:


Closeup of same picture:



ECU Mounting Plate with circuit board removed:





So, I guess that the lesson learned here is be sure to spray your truck for ants and bugs. A $3 can of insecticide could've saved about $300 in repairs...

My ECU is off to the repair dudes via Fedex 'cuz a couple of ants nested inside it...I hope someone gets a good laugh outta this one, I know I did... <img src="/forums/images/graemlins/kewl.gif" alt="" />

1989 ECU's only directly interchange with 89 Raiders & monteros as the Hollander Interchange program tells me here at work.

Ed

That's correct - the '90s and '91s used a different distributor and ECU..... '89 was a 1-year run for distributor and ECU.

Frank

**UPDATE**

Well, I got myself a rebuilt ECU from a seller on eBay, and even without a core charge! I got a GREAT deal and for a little more I got "extended warranty" on it. The seller offered 30 days and a non-DOA, and for 10% of the price he offered 1 year to return the unit if it dies on me.

I plugged the ECU in, and it's been working perfectly. I'll give it a final run before I spray it for bugs!

Click HERE for the seller's eBay Store.

Thanks to everyone that helped me diagnose my problem!! <img src="/forums/images/graemlins/smile.gif" alt="" />