Monday, April 19, 2010

Installing 88 Engine in 83 944. Solving Wiring Issues.

Chuck Taylor(national director of SPEC 944), Chris Venturini(SPEC racer) and a couple of other folks helped me install my new 944 Motorwerks engine over the weekend. The old engine was unbolted and new engine bolted in within four hours. Then it took another six or so to get the wiring worked out. Hopefully the below will help anyone in the future to do this swap. Especially as it combines the benefits of an early chassis(light weight, steel control arms, manual rack) with the benefits of the late 88 motor(higher rev limit, tad higher compression).

Mating the harness of an early (1983) car and late (1988) engine and ECU is pretty straightforward. The biggest challenge being connecting the new engine harness to the old chassis harness because they have different connectors. The early car has a 9-pin square shaped connector, the later car has a rectangular 14 pin connector.

Luckily, 90% of the wire colors and functions are the same.

Before hooking up the wiring, it is beneficial to take the old 9-pin connector from the engine harness and use that as a base so that in the future you can easily disconnect the harness. So, what happens next is you permanently splice the pigtails from the old harness' connector onto the clipped wires from the new harness.

As your splicing them It is pretty much straight forward Pin to Pin ie Pin #1 to pin #1. all the way to 9/9.

All the colors match up directly except for a few. There are 2 wires on the 14 pin connector We did not use. Those are: pin #10 and pin #13.

Pin #10 (blue/green) wire on the new harness. This is for the water temperature dummy light, a feature non-existent on the early chassis. So, just cap this wire, and pin # 13 red/green, is used for the air conditioner.

There are now two plain black wires on the old chassis harness that we need to take care of. These emerge from the #2 and #4 positions on the connector.

The number 4 black wire goes to the tach. So, a jumper wire needs to go from this wire to the black/yellow + black two wire connector that is part of the new engine harness. It is a lone split from the main engine harness and it is pretty obvious from its position that it is a dash wire.

The lone remaining black wire off the old #2 connector is for the O2 sensor warmer. On a race car this is not needed. So, this wire can be capped. Or, as it is hot with ignition, used to power additional gauges, which is what I did. I used this to power the low oil pressure light and oil temperature gauge.

That's it!


Nolan Harris said...

Good work here. I find myself looking at this very swap I have a crashed 89 automatic and a solid 84 with a whooped engine. Looks pretty straightforward. Any words of advice? (motor mounts etc?)


Unknown said...

Very helpful

David LLANO said...

By any chance do you know what the extra two plugs are that r going with the wiring harness inside