94 Q45 engine Installed in 91 Q45 car (needing advice)

[mosr20]

First off --- yes I searched and am more confused than I was before!

I just pulled a good motor/transmission out of a 94 Q45 parts car I have....

I'm putting the motor in a 91 q45 I have thats in good shape but it has a rod-knocking motor.

It seems there are major differences in the 90-93 q's versus the 94+Q'sfor example:1) heads (dual ovals on earlier models & single runner on 94+)2) injectors3) electrical connectors and wiring4) the 94 had hydrolic ride height adjustment so I imagine the PS pump differs...

Please shed some light on how I should attack the swap......

I cant swap the intake runners for the old ones and old injectors unless I swap the old 91 heads on the 94 motor...PITA

OR

I could take the engine wiring harness and ecu of the 94 donor car out and use the 94 ecu and engine harness in the 91 car to make it work..... (might have to change to the 94 dash cluster though)

please chime in if you've done the swap or know someone who has and can give some suggestions.....

I'm getting ready to pull the 91 Engine out in the next day or 2 and I need to plan what route of insanity I'll be taking.

let me know~

Damon

[Rex]

Searched recent and archived posts by SOCAL91Q45a

He did something similar, but as I recall had to pull some fo the older moltors externals off and put on the newer motor.

Good lcuk.

[Q45denver]

The 94 should work OK with your ECU and existing wiring. You might have to swap the P/S pump and some of the connectors may be different. The 94 FI system is much better - so don't mess with the heads if at all possible.

[mosr20]

yeah... I wanted to leave the heads and newer injectors on the 94 motor,..... however the connections on the top rear pass side of the plenum looked to be a bit different.....

If they are -- I need to know that BEFORE I put the motor back in....

changing out the engine harness is MUCH easier with engines OUT of the car....

I'm just trying to find someone that HAS done it before and can tell me what they did.... Hopefully....

[Q45denver]

What are the connections that are different connecting to? It might be easier to swap out the component with one from a 1991 rather than trying to splice in a different connector.

I'm currently in process of swapping a 1994 FI system into my 1990.

[elwesso]

the connections for the coils, injectors, CAS is different.. You could keep the 91 coils on the 94 engine and itd work fine... Injectors shouldnt be an issue becaues the subharness connector is the same.

The way I see it, it s a lot splicing..

[Q45denver]

The connector for the FI subharness for my 1990 looks the same as the one on my 1995 and all the pins are in the same position. If you are talking about the individual connectors to the injectors they are very different.

[3Q Jay]

you are saying the '94 is an active suspension? the PS pump is different, so you'll need the '91 ps pump. but then you'll also need the 91 crank pulley and wp pulley to match. then, you'll also find that the wp snout dimensions are different on 90-93 from 94.

iif it were me, i'd get a new 91 wp to fit on your 94 block, swap the crank pulleys and change out your front seal while the pulley is off.