Need ECU swap info help

[luvmygst]

Does any one know what it takes to make a 1990 computer run a 1991 car? I have a 90 tsi AWD, and a 91 tsi AWD.. I just got my 91 on the road and the second day the computer smoked (literaly) I have a 90 computer sitting here and I plugged it in and everything seems fine. Am I going to hurt any thing like this? Is there any wires I need to change around? Or anything I need to do? I appreciate any help. Thanks

 

[1gjosh]

swap out pins 6 (idle position switch) and 14 (air flow sensor active filter reset). http://vfaq.com/index-main.html

 

[1gjosh]

heres an illustration

 

[luvmygst]

Those articles are for people wanting to switch and put a 91-94 ecu into a 90. I am doing the oppisite, I need a 90 ecu into a 91 car. It shoud be close to the same thoug I would think. Thanks

 

[GST with PSI]

I believe your tachometer will probably be inoperative. The 91 and later cars used a different tach signal converter and aren't compatible with the 90's. This is also the reason the latter 1G coil on plug setup won't work on a 90 DSM. In order for the car to work properly, you have to basically retrofit your current 90 1G ignition system with a 91 or later 1g system. I would suggest buying a 90 year model computer from ebay. It would prove much less complicated.

 

[steve]

It shoud be close to the same thoug I would think.

Putting a 90 ECU into a 91+ car is easier than putting a 91+ ECU into a 90 car. For what your trying to do the only thing you have to do is swap pins 6 and 14.

It would be a good idea to identify why he 91 ECU burnt up so you don't repeat the process.

Steve

 

[1gjosh]

you still swap 6 and 14. Thanks for clarifying that steve.

 

[luvmygst]

Steve you rock. Im not sure why the first one toasted. I got the car with a bad computer. It had on cap that was obviously leaking, so I changed that one and me being in a hurry did not change the other two. Could that have somthing to do with it? It ran fine for 3 days with no problems then for no obvious reason smoke??? Could that have somthing to do with it? Oh yea and a little while before it happened I hit fuel cut. I put on a MBC and one of the lines came off, and it went to almost 20psi. I fixed that and it ran fine then about 30 minutes later I had a smoke show in the car. Thanks for all the help guys.

 

[steve]

Who knows what happend without looking at it. There are several ways the car can burn up an ECU and lots of people who have burned up one right after another because they didn't stop to figure out why before they stuffed another ECU in. They make expensive fuses.

Steve

 

[luvmygst]

Other than the MBC The car is totally stock. I just picked it up. I found the deal of my life. The car has never been modded, its in almost perfect shape with only 110k. And I got it for $450. That could have been one of the cest days of my life Thanks for you input though Steve and keep it coming if you have any thought on what I should check. Thanks again.