Ok, well i just dropped a 1990 v6 into my 1991 v6 5spd truck and when i went to plug the harness into the ecu the plugs were different!! I have been trying to talk to the salvage place i got the motor from to get more info but i am not really having any luck. I REALLY don't want to have to swap harnesses does anyone know if i will have any trouble using a 90 ecu ?

Anyone out there have a 1990 ecu for a truck with a 5spd v6 and 4wheel drive?

Guess i got excited to see the motor in the truck alittle to quickly.. ahh well.

 

im quite suprised they would completely change the ECU connectors, you're definetly gonna have to get the ECU from the same year as the motor then. . . or if worst comes to worst solder the wires from your old ECU harness to the new engine harness. The locations on the plugs should be the same even if the shape changed but i'd check wiring diagrams before i did that.

 

All good points, these are some of the things i am already thinking about i was just hoping to get some confirmation from someone maybe. i seriously don't want to have to swap engine looms. i don't see why getting a 90 ecu and running it wouldn't work but the place i got the motor from said it wouldn't.... but they might just be covering their asses. guess i was just hoping someone here had swapped a 90 into a 91... or vice versa...

 

If the new motor you got was from an auto tranny than that would explain the difference in the harness connectors.
If you cant find what your looking for try Here to see the differnet part numbers. Good luck to you.

,Thomas

 

if this motor was from an auto... does that mean i am screwed unless i swap harnesses? or could i cut an splice the plugs? whats different about an auto and manual harness?

 

i found that the harnesses between a 90 and a 93 were different. both we 5speeds, but the engine was from a pickup and it went into a 4runner. I ended up having to use the harness from the 4runner. yeah it required removing the intake and all and a few splices, but it was alot easier than trying to swap out the computer and having to deal with all the wiring under the dash. i thought id be able to just keep the computer from the 93 and leave the 93 harness attached, but there is alot of wires under the dash as well that plug into the wiring harness that runs into the engine bay. if you have any other questions let me know, i just did it this past weekend
-andy

 

Kerap

 

sorry man, but you could do it if you also replaced all the under dash wiring with the wiring from the 1990. or got the wiring chart and spliced all those wires in to the connectors that plug into the other half of the wiring harness(that goes into the engine bay). i know its a pain and all and you gotta ask you self why in the hell would they change it so much in that time
-andy

 

there is a total of 5 plugs i believe on the main loom coming in from the bay. two of these plugs look identical to the ones on the 91 harness, these two are the ones that plug into the dash harness i think. the three that plug directly into the ecu are different though. i am really tempted to just cut those plugs off and connect the 91 plugs...

did i miss something or can i do this?

 

well if the plugs match between the half under the dash and the half in the engine bay then all you need is the computer from the 90 or like you said, find out which dow hat and splice the plugs from the 91 onto it and use the ecu from the 91. that makes it alot easier. the plugs between the dash half and the engine bay half on mine were completely different so thats why i decided to just keep the harness, ecu, etc from the 90 and connected it to the 93 engine
good luck,
andy