Tips/Lessons Learned for 85 ECM Upgrade
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
You can run a BIN from '89, which didn't have the cold start injector. It richens the mixture at startup to compensate.
I think you could still use the MAF module if it works OK for you now. It has a fancy relay and some electronics in it but does the same thing as the MAF power and burnoff relays in the later cars. You'd have to check to make sure the polarity of the signal from the ECM to the MAF module is compatible.
I think you could still use the MAF module if it works OK for you now. It has a fancy relay and some electronics in it but does the same thing as the MAF power and burnoff relays in the later cars. You'd have to check to make sure the polarity of the signal from the ECM to the MAF module is compatible.
Thread Starter
Melting Slicks
Joined: Mar 2008
Posts: 2,141
Likes: 76
From: Santa Maria, CA
this is what i used when i did minehttp://forums.corvetteforum.com/c4-s...m_id=82&arch=1
just needed to buy the 2 relays and harnesses. i cut off the old C12 pin and used it for my new D12 connection. i used a recycled ecm from a tpi f body i think. it was really pretty simple if you have all the re-pinning connections and the relay wiring worked out
i do my own tuning and data logging with a Moates Autoprom and Tunerpro RT along with a wideband o2 sensor in the passenger header collector.
just needed to buy the 2 relays and harnesses. i cut off the old C12 pin and used it for my new D12 connection. i used a recycled ecm from a tpi f body i think. it was really pretty simple if you have all the re-pinning connections and the relay wiring worked out
i do my own tuning and data logging with a Moates Autoprom and Tunerpro RT along with a wideband o2 sensor in the passenger header collector.
Thread Starter
Melting Slicks
Joined: Mar 2008
Posts: 2,141
Likes: 76
From: Santa Maria, CA
From what I've seen, better control of warm-up performance was likely the biggest gain from 85 to 86. IOW, most of those extra BIN parms are in areas of warm-up control. I think there's also a couple of extra for idle control too. I would suggest that emissions and AFR control had to be better as well...especially when they went to the 2-stage converter system that came on my 89 car. (I've never had any other car with such a clean looking exhaust pipe.)
If somewhere you read that ALDL is separate, I could believe the storage locations...and even the interface to the ALDL connector are separate modules. Though theoretically possible for modules to be significantly slower than the main "CPU", I would doubt it. I GOTTA think clock speeds improved greatly (as implied above) providing a huge step in sensor feedback. That's GOT to translate to a cleaner-running motor. Probably better response/power too. (I don't remember power increase numbers between 85-86.)
If somewhere you read that ALDL is separate, I could believe the storage locations...and even the interface to the ALDL connector are separate modules. Though theoretically possible for modules to be significantly slower than the main "CPU", I would doubt it. I GOTTA think clock speeds improved greatly (as implied above) providing a huge step in sensor feedback. That's GOT to translate to a cleaner-running motor. Probably better response/power too. (I don't remember power increase numbers between 85-86.)
So I'm hoping the clock speed does translate to better emissions. GM was under a lot of pressure in the mid 80's to improve emissions. I'm hoping that was a driving factor in why they upgraded the ECM.
Thread Starter
Melting Slicks
Joined: Mar 2008
Posts: 2,141
Likes: 76
From: Santa Maria, CA
You can run a BIN from '89, which didn't have the cold start injector. It richens the mixture at startup to compensate.
I think you could still use the MAF module if it works OK for you now. It has a fancy relay and some electronics in it but does the same thing as the MAF power and burnoff relays in the later cars. You'd have to check to make sure the polarity of the signal from the ECM to the MAF module is compatible.
I think you could still use the MAF module if it works OK for you now. It has a fancy relay and some electronics in it but does the same thing as the MAF power and burnoff relays in the later cars. You'd have to check to make sure the polarity of the signal from the ECM to the MAF module is compatible.
I'll look into the 89 BIN. That could be a useful feature considering I never intend to go back to a cold start injector.
