ECU questions for turbo swap 1G

[terminaltsi]

ok, i put a 91 gvr4 engine in my 90 ggsx. i have a 1991 ecu but as we all know the 90 and 91+ ecu's are different. i havne't fired it up yet.

i've been searching but can't find the conclusive answers to my questions.
when i put in the engine, i changed the CAS to the 90 pigtail style so it would just plug in.
will this work ok with the 91 ecu?
also, i've read that the tach won't work properly without some wiring changes. assuming i don't need the tach right away, will the 91 ecu start and run the car without changing anything?
i'm using the 91 transistor and coil pack from the vr4.
if i put in a 1990 ecu, will that run the car or will i have to change the transistor and coil pack to the 1990 style?
i'd rather use the 91 ecu since i have it sitting here.

thanks.

 

[Jake90GSX]

if it dont work out mate then just do some searching at online parts dealers and call some junk yards, try and find a 90 ecu on the cheap, I wish ya luck, knowing that the 91 and 90 ecu are different and the tach and maybe other stuff wont work is more than enough for me to not even bother with the 91 ecu and just get the 90 you need. Anyway, best of luck to you.

 

[nightspeed87]

everything should work except the instrument cluster stuff like the tach that you mentioned. And make sure its not a california emissions model because that could throw check engine light if your missing some of your egr equipment. If your using the harness for the 90s ecu that your putting in everything should be fine.

 

[steve]

i've read that the tach won't work properly without some wiring changes. assuming i don't need the tach right away, will the 91 ecu start and run the car without changing anything?

It should start assuming you don't have other problems but it will run better if you swap 6 and 14.

You may have tach problems with this setup no matter what you do because your running a 91 transistor and coil pack. The quick fix for '90 cars and 91+ ECUs was to leave the tach running off the original tach circuit coming from the '90 coil pack tach gate and noise filter and run the ECU from the '91+ power transistor. You have a weird hybrid and will have to let us know how your tach gauge likes the later tach signal from the PTM.

Steve

 

[terminaltsi]

It should start assuming you don't have other problems but it will run better if you swap 6 and 14.

You may have tach problems with this setup no matter what you do because your running a 91 transistor and coil pack. The quick fix for '90 cars and 91+ ECUs was to leave the tach running off the original tach circuit coming from the '90 coil pack tach gate and noise filter and run the ECU from the '91+ power transistor. You have a weird hybrid and will have to let us know how your tach gauge likes the later tach signal from the PTM.

Steve

well, i'll post the results once everything else is lined out and i get the engine fired up.l