swapping from 93 lt1 to 96

[MikeE24]

Hey guys I just bought a 93 trans am with a seized engine and am getting a motor from a 96 trans am to swap in. Just wondering if there were any differences that would make this difficult. I know the intake and timing cover is different, anything to worry about beyond that.

[Injuneer]

Appears you are already aware you have to swap the intake and fuel rails because of the location of your 93 fuel lines/connections. You do not need to change the timing cover. It's different because it has a vented Opti (you want that), and the crank position sensor (you don't need that, so you just don't hook it up). Leave the sensor in the hole to plug it up. You will need to add the connections for the Opti vent harness. And, the 96 Opti has a different plug than the 93, so you need the harness that goes from the side of the intake to the Opti (Casper sells it cheap).

You need to swap your 93 knock sensor into the 96 block because the 93 ECM will not work with the 96 knock sensor. Your throttle body will need to be swapped, since the 93 IAC motor/connection is different. If you have an A4, you need the TV cable connection that only the 93 throttle body has.

You will want to swap the exhaust manifolds. The AIR and EGR connections are different 93 to 96.

[Jeff_in_Atl]

You may have to move the oil pressure sensor or rig an extension to the harness. On the 96 it on the back of the engine, on the 93 it's on the side. I'm not sure how the wire is routed.

[MikeE24]

Thanks guys for the responses. I believe I'm getting the fuel rails and intake with the motor so that's no problem. The rest I'm gonna be on the lookout for. Forgot to mention that the car is an A4, need to update my sig I guess.

[Injuneer]

But the 96 fuel rails will connect to the supply/return lines at the rear of the driver's side, not where they connect on your 93. You can buy the (94-97) plastic lines than run from under the drivers side door to the (94-97) rails for less than $20. And, the 96 rails will not fit on the 93 manifold.

Also a question of whether the 94-97 rails are correctly designed to properly support (pressure drop) the batch fire injectors in the 93. The 94-97 rails are designed for sequential fire. May be an issue of pressure loss in the rails when one complete bank of injectors fires simultaneously. Not sure.... just thinking out loud.

[MikeE24]

Well, I am getting accessories with the motor too, minus a harmonic balancer. So I'm hoping it comes with rails and an intake. I thought about just swapping the whole pcm but that wouldn't work with the 93 tranny I believe. Guess I'll just have to keep an eye on the fuel pressure when it all comes together. I'm going to Mississippi to pick up the motor tomorrow, I'll let y'all know how it goes.

[Injuneer]

If you swap the PCM, you'll have wiring issues to address. The 96 has sequential injection with 8 individual wires from the PCM to each injector. The 93 wiring harness only has two wire, one for each bank of the engine, that then split into 4 connectors for the batch fire injection. You would also have to add the MAF sensor wiring for the 96. And, since 96 is OBD-II you'll have to wire up the CKP sensor, the EVAP vacuum detection switch, the after-cat O2 sensors, etc., etc. You can substitute sims for the rear O2 sensors, or have them programmed out of the 96 PCM. Could have most of the other unsupported diagnostics programmed out as well. And, since a 93 A4 would be the 4L60, you would have to do something about all the codes you would get for the missing electronic tranny interfaces.

[MikeE24]

I think swapping the pcm is not worth the hassle and money, as right now I'm just trying to get this car working for as little money as possible. Got the motor on Sunday out of the 96 car and it has an intake but no fuel rails, and is missing the harmonic balancer. I believe the balancer from the 93 motor should work, time to shop for fuel rails and hook this motor up. Also what/who is casper? Need to get that harness for the opti. Also can anyone tell me how to change my signature I can't get the user CP option to work.

[sneitzel]

Use the edit signature option under the Quick Links tab to adjust your signature.