I need to know if the caprice (1995) and the camaro(1994) wiring harness's are interchangeable at the ecu on a LT motor. I am using a caprice computer and a camaro wiring harness. I have cut and customized the harness to fit in my 88 camaro so adding the second knock sensor to the harness isnt a big deal. The concern I have is that I used wiring diagrams for a 95 Camaro to make the harness and re-pin the ecu connectors. I am using a Caprice ecu though. Will I be spending another several hours re-pinning the harness AGAIN or are they the same at the ECU connections? Can anyone point me to the pinouts for the Caprice harness if I need to change them. Also I am unsure where the second knock sensor pins in on the ecu connectors.

 

All LT1 ECMS from 94-97 have the exact same pinout.

ECM Pinout: http://lt1swap.com/lt1_pcm_pinout.htm

Using the F-Body harness makes life a lot easier, as you have to completely dissassemble and track each wire down with an ohm meter for the B-Body harness and the ECM is engine bay mounted.

 

Ive built several LT1 harnesses and prefer to start with the B-body ones

To clear up a few misconceptions, the PCM pins did change slightly over the years

93 is its own year, 94-95 are the same short of the PWM wire for auto trans cars and 96-97 were the same. A cool tid-bit was the 94-95 PCM can control a 96-97 motor just by swapping the older PCM directly on there. The late models switched to OBDII and required a few extra sensors (namely the crank) and used a more powerful PCM that was a bit more difficult to tune

B-bodys used two knock sensors, but teed them together and ran them to the same pin at the PCM. For your Fbody engine, figure out which side the knock sensor best clears the headers and only use that side

If you're using a 4L60E, then wire it for a +95 pinout. If using a 94 or older trans, just snip the PWM wire (pin U at the trans connector). That way if the trans ever dies you can swap a newer version in by just reattaching one wire

T56 or other non computer controlled transmissions dont care what PCM you use (if any)

Another ting that grinds my gears, its not an ECM any more once it gains the capability to control an electronic transmission. It stands for Engine Control Module. Older TPIs and the like have ECMs. 94-97 LT1s have PCMs. When the option of trans control was introduced, name changed to a more fitting Powertrain Control Module

 

My humblest apologies for the mis-used terminology oh wise one of the third gen forum...LOL
Perfect so the knock sensors are on 1 pin together interesting....my harness is ok and I dont have to repin it...
I used a F-body harness and traced it all down after repinning it all at the PCM connectors with the diagrams from shbox and this site. Its all cut and extended and setup like a stand alone harness for the LT PCM. Just needs power and grounds to the proper wires as well as connected to guages in car etc. I am running a 700r trans cause Im broke and doing this with what parts I have available. The car came with a GM refurbed new trans so Im going with that. I know this means converting to the 93 throttle body etc. What wires do I need to connect to the trans both from the LT harness and on the 700r connector. I believe the trans is for the car specifically so it should be a 88 model trans or same as anyways. I want the TCC lockup to work as well as have the option to monitor the temp on the trans once I get the guage for it. Is this possible or do I need to put the TCC lock on a switch? Im also unsure where to wire in the fuel pump prime and signal wires from the PCM to the car. Just trying to get all this figured out before my computer gets back at the beginning of next week so this will be a smooth easy process to get running.

 

Converter lockup requires either a manual switch or an aftermarket vacuum switch. BTO has a few kits for that

Glance over this for your gauge and relay connections

https://www.thirdgen.org/forums/ltx-...formation.html