96bluez28

So I found a decent deal on a used 94 LT1 to put in my 96 car. The engine comes with the harness and PCM. My car is an automatic and the 94 engine was paired with a six-speed. I am being told that I will need to swap the flywheel but what else will I need to do in order to make the 94 engine work with my automatic transmission? Would it be easier to use the 94 harness and PCM or just use the ones from my car?

pizzi-man

I would use the pcm from your 96 and change the timing chain cover for the 96 to the 94 motor unless there is a reason to change the pcm

Injuneer

You need to swap the entire front of the 96 engine to the 94 engine, if you want to keep the vented Opti on your 96, and want to incorporate the crank position sensor from the 96. This would include:

-timing cover
-vented opti
-short Opti harness
-timing set
-camshaft/dowel pin
-CKP sensor
-CKP reluctor wheel
-damper hub
-crank sprocket/reluctor wheel key

If you keep your 96 PCM, you also need to install the 96 knock sensor on the 94 engine.

Transfer EVAP vacuum detector switch and hoses.

To use the 96's AIR plumbing, you need to use the 96 exhaust manifolds (or headers).

The 94 PCM could be used if you want to switch from OBD-2 to OBD-1 (do you have an emissions inspection where they connect to your ALDL connector to look for the VIN, system ready flags and trouble codes? - if so, you need to keep the 96 PCM).

The down side to using the 94 harness with the 96 chassis is a mismatch of some of the pinouts where the engine harness connects to the body connectors.

If you plan to keep your 96's 4L60E, you have to use the 96 PCM. 94 PCM can not control the pulse width modulated converter lockup that was introduced in 1995.

96bluez28

Wow. Thanks for the detailed response. The state I live in does have emissions inspections, I hadn't even thought of that. Sounds like it might not be worth the hassle. Do you think the 94 engine would pass inspection?

shoebox

If you put all the stuff from the 96 on the 94, there will be no real difference.

Injuneer

Do they plug into your vehicle's ALDL connector as part of the inspection? If so, you have to keep your 1996 OBD-II PCM. You will not have the crank sensor on the 94 engine if you don't swap it over from the 96. You can have the 96 PCM reprogrammed to eliminate the code for the missing crank sensor, since a missing code, or a "system not ready" reading may cause you to fail inspection.

You would have a similar problem without the EVAP system vacuum detection switch that is on your 96 but not on the 94. But that's an external part that is easy to switch over.

96bluez28

I am not sure what they plug into during inspection but it sounds like I should just keep the 96 harness and accessories. I was nervous about trying this but after all of your advice I think I am going to give it a try. Thanks again. Your knowledge of these cars is awesome.