Need 85 Engine Computer
Thread Starter
Instructor
Joined: Dec 2004
Posts: 136
Likes: 0
Need 85 Engine Computer
I would put this in the for sale/wanted section, but I have a technical question too. I need a new ECM, for my 85' auto, because the EGR function isn't working anymore.... http://forums.corvetteforum.com/show....php?t=1014606
So... when I first got my car, someone suggested that I get the ECM out of an 89' because it was a better computer. Is this true??? if so, what is better about it??? and do I have to do any re-wiring??? I don't know if I want to mess with the wiring, but if it's not too hard, and if the performance gain is worth it, then I may consider it.
So if anyone out there has an 85' or (89' ? ) ECM that they know is good, and they want to sell, let me know. I'm ready to be done with
so I can start 
again
So... when I first got my car, someone suggested that I get the ECM out of an 89' because it was a better computer. Is this true??? if so, what is better about it??? and do I have to do any re-wiring??? I don't know if I want to mess with the wiring, but if it's not too hard, and if the performance gain is worth it, then I may consider it.
So if anyone out there has an 85' or (89' ? ) ECM that they know is good, and they want to sell, let me know. I'm ready to be done with
so I can start again
Team Owner
Joined: Sep 2001
Posts: 62,155
Likes: 1,731
From: Athens AL
C7 of the Year - Unmodified Finalist 2021
C4 of Year Finalist (performance mods) 2019
The 85's computer is rather slow, the 89s is better, but there is no performance gain to be had just by switching ECMs.
The gains come in with other modifications to the engine and the following chip programming for those mods.
The gains come in with other modifications to the engine and the following chip programming for those mods.
Racer
Joined: Dec 2003
Posts: 277
Likes: 3
Originally Posted by kcpaz
I would put this in the for sale/wanted section, but I have a technical question too. I need a new ECM, for my 85' auto, because the EGR function isn't working anymore.... http://forums.corvetteforum.com/show....php?t=1014606
So... when I first got my car, someone suggested that I get the ECM out of an 89' because it was a better computer. Is this true??? if so, what is better about it??? and do I have to do any re-wiring??? I don't know if I want to mess with the wiring, but if it's not too hard, and if the performance gain is worth it, then I may consider it.
So if anyone out there has an 85' or (89' ? ) ECM that they know is good, and they want to sell, let me know. I'm ready to be done with so I can start again
So... when I first got my car, someone suggested that I get the ECM out of an 89' because it was a better computer. Is this true??? if so, what is better about it??? and do I have to do any re-wiring??? I don't know if I want to mess with the wiring, but if it's not too hard, and if the performance gain is worth it, then I may consider it.
So if anyone out there has an 85' or (89' ? ) ECM that they know is good, and they want to sell, let me know. I'm ready to be done with
so I can start again
Instructor
Joined: Jan 2005
Posts: 141
Likes: 0
From: Tucson AZ
I concur with the Autozone suggestion
I got a rebuilt ECM from autozone for $79. Everything after that was better.
Mine was throwing (false) codes, and also failing to throw codes. And it wasn't giving stable directions like it should.
I guess after 20 years of checking things and issuing instructions, it was pretty tired......
I also put in a new chip from TPIchips (what a bargain at only $70!). Wow, the car runs fabulous with that new chip. And it doesn't lag into TC lockup early anymore. The fan goes on at 200, and the car has great power in all throttle and speed ranges. It has a very different and much more agreeable driving personality now.
I have followed your dilemma. I have a feeling you're almost there.
I bet your next post will be something real happy.
Mine was throwing (false) codes, and also failing to throw codes. And it wasn't giving stable directions like it should.
I guess after 20 years of checking things and issuing instructions, it was pretty tired......
I also put in a new chip from TPIchips (what a bargain at only $70!). Wow, the car runs fabulous with that new chip. And it doesn't lag into TC lockup early anymore. The fan goes on at 200, and the car has great power in all throttle and speed ranges. It has a very different and much more agreeable driving personality now.
I have followed your dilemma. I have a feeling you're almost there.
I bet your next post will be something real happy.
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Melting Slicks
Joined: Dec 2004
Posts: 2,954
Likes: 2
From: Obama=death for America
Check ebay's auction site first before you plunk down $80-$100 for an ECM. You can get one for much less money when they're available. It's hit or miss when they're up for sale on the auction.
http://cgi.ebay.com/ebaymotors/ws/eB...category=33596
http://cgi.ebay.com/ebaymotors/ws/eB...category=33596
Racer
Joined: May 2004
Posts: 270
Likes: 0
From: NORFOLK VA.
Do you have the stock prom in your ecm?I have a 85 also with a mini ram so I turned the egr dianostic function off you may have somebodys performance chip that has started to take a dump get a scan done on the ecm and get the prom number 2531&7805 are just two that come to mine,I have had a (performance chip) that I purchased do some strange things. 
