1G 90 ECU in a 91 car

[Eniygma]

I read the VFAQ on swapping the ECU from a 90 to a 91, and wires 6 & 14 need to be swapped. I have a A/T 91' that will be converted to stick this weekend with a 90' M/T ECU. I would assume that these two wires would also have to be switched, going from a 91' vehicle to a 90' ECU, yes?

 

[sweet97]

Check the part #'s on the ECU's. For example the AWD ECU's changed in the middle of June of '90 so in this case some '90 and '91's have the came ECU. mark

 

[steve]

Check the part #'s on the ECU's. For example the AWD ECU's changed in the middle of June of '90 so in this case some '90 and '91's have the came ECU. mark

Mark, I tried telling you before that's not the case. The switch over in part numbers for the ECU matches the change in model years. There is no overlap.

Eniygma, you will need to swap the two pins. Thats what I do when I test '90 ECUs in my car.

Steve

 

[sweet97]

I've got it now Steve. I thought some '91's could have either ECU but during june of '90 they switched from producing '90's to '91's, Correct?
Is it possible, difficult to put my '91 ECU into a '90? If possible what would be involved? Thanks, mark

 

[steve]

Yes, that's when the factory switched from making 1990s to making 1991s.
Because of the changes made starting with the 1991 models there are some issues with putting a later ECU in a '90. There are two pins (6 and 14) that changed positions in the large ECU connector but the bigger issue is with the tach setup in a '90. The gauge, power transistor module, ignition coil assembly, noise filter and the wiring also changed.
The reports are that causes 90s with later ECUs to have tach problems. The '90 model ECUs work in the later cars with just the pin swap not that you would want to use one unless you had to. The Later ECUs have better code than what's in the '90 ECU.

Steve

 

[pianoman]

hmm, my tach jumps when i let my car warm up at idle. it just blips real fast. I don't know what year my ecu is from since it was just a spare i had at my garage, but i haven't noticed any other problems with it.

 

[oldman]

Hey guys, I'm about to purchase a 91 MT AWD EPROM ECU to install into my 90 Talon. My ECU part# is MD166262 which according to VFAQ, a Federal MT 6/90 to 6/92.
Does this mean I don't have to swap the wires? If so, is my car a 90 or a 91?

Thanks.

 

[steve]

Sorry, you have to swap the wires with a MD166262 and very possible you'll have tach problems too if you car is a '90 model.
The MD166262 is '91 & '92 model year AWD ECU.

 

[oldman]

Sorry, you have to swap the wires with a MD166262 and very possible you'll have tach problems too if you car is a '90 model.
The MD166262 is '91 & '92 model year AWD ECU.

Thanks Steve, what I meant is I have MD166262 in my car right now, My car was produced after 6/90. I didn't get a chance to ask him for his part number yet, meeting him tomorrow. If his number is also MD166262, will I still have to swap the wires?

 

[steve]

Sorry I was going by the '90 you have listed. If your car was built after 6/90 it should be a '91 as far as I know, but maybe talons are different.

If you have a MD166262 in now and you get a MD166262 EPROM they would have the same pinout.

Steve

 

[oldman]

My title and registration says 90...but 91 sounds younger. Thanks Steve.

 

[garyt83]

Hi, I was wondering where can I find the part number for my ECU? I dont have the ECU with me. I have a 91 2.0L Eclipse GS. Also if my ECU is burnt, is getting a used ECU a waste of money? A new rebuilt ECU will cause $200 and I can find a used one for only $80 on ebay. I was wondering if I should make that investment.

ALso, Ive read that ECU's only last for a few years because of the heat. What should I do to reduce the heat at where it is installed which is behind the console. Thanks alot

 

[foreverinvayne]

I was wondering where to look on the car to find out the year it was made... and how do you know if an ECU is an eprom or not... thanx

 

[oldman]

http://www.vfaq.com/mods/ECUs.html


http://www.tmo.com/howto/ecu1g/checkeprom.htm

 

[sleeper96]

i need an ecu for my 90 talon and as the 90's are hard to find is there anyway around the tach problems by say burning a chip for it

 

[Mirage2LTurbo]

Here's an idea:

Plug it in, if it doesn't run right, switch the wires. It's BLATANTLY obvious if you need to switch the wires. It won't hurt anything, I did it before not knowing what year an ECU was.

 

[oldman]

i need an ecu for my 90 talon and as the 90's are hard to find is there anyway around the tach problems by say burning a chip for it

Yes, but the ecu would have to be an eprom ecu. What's wrong with your 90 ecu? Pm steve, he just fixed mine.

 

[sleeper96]

i dont have an ecu car didnt have one when i bought it i had planned to get an eprom anyway but the 90 eproms are rare although i have found a few for sale theyre pricy for that reason

 

[steve]

i need an ecu for my 90 talon and as the 90's are hard to find is there anyway around the tach problems by say burning a chip for it

Sure you can replace the gauge cluster and ignition wiring with those from a '91+ car. To me that seems excessive to fix a flaky tach. You can't fix this in the software, it's a hardware issue.

I haven't had the chance to sit down and really figure out why this happens. Not having a '90 to experiment on makes it difficult to figure out if I could make a simple fix. I have some ideas that might work.

Steve

 

[sleeper96]

well actually on second thought the 91 to 94 eproms arent any cheaper really but i was gonna burn a chip for which ever one i got anyway. so if i can make it work on a 90 while burning the chip it gives me a wider range of ecus to chose from while im shopping for one instead of just having to stick to a 90 model computer

i guess im stuck lookin for a 90 then thats all i needed to know thanks steve