brharris27370

Ok, I bought what I thought was a good deal on a 94 LT1 Firebird that didn't run after the owner replaced engine with a 95 Camaro LT1. The car is a mess. I don't see anything cut but it looks to me like they removed the 94 LT1 engine harness clear in to the dash and put the 95 harness in. Why I am not entirely sure but the plug for the body control module doesn't match the 94 body control module and so I am sure that is part of the problem. Everything else appears to be plugged in ok but I am getting no spark from the ignition system so I put my new 95 opti that I have for another project and that didn't cure the spark issue so I hooked up my laptop to the ALDL with TTS datamaster and I can't communicate with the ECM. I am going to check the power wires for the computer to see if I can determine if its getting power or not.

I have the 94 wiring harness still and my feeling is to remove the 95 harness and put the 94 harness back in. The thing there is there any parts other than the 95 opti that I need to look out for. I see the 95 cars have a cranksensor which I don't think 94 cars have. Is that going to be a problem with putting the 94 harness back into this car.

Please give some pointers on how to make this poor Firebird run again.

Injuneer

95's do not have a crank sensor.... it was added in 96 for OBD-II misfire detection. I thought they didn't add the BCM until 1996 either.

Are you sure the car's ALDL connector has the data pin (light tan wire) in the correct position for the DataMaster cable?

brharris27370

I thought that about the crank sensor too but the plugs for the PCM are the same and I have both PCM's and they are both the same. Also the 94 car has 2 02 sensors and this 95 has 4 02's but I am not to the point of worrying about he 02's yet. Under the dash is still the 12 pin aldl plug and I know my TTS Datamaster OD works fine in the 12 pin connector on my 94 Truck so the EE should work fine in the 12 pin plug on my Firebird. Also, I have noticed no check engine light in my dash when I turn the key on. I just get the check gauges and I get a ABS Inop light.

red94chicken

ok.. so the 95's don't have 4 o2 sensors you must have a 96 or 97.. and you would have to repin two of the connectors that comes inside of the car by the heater core.. i had the same problem not being able to communicate with the computer when i had a 95 harness.. and it won't start cause you need to supply the pcm with a power.. its the orange wire. i had my old 94 harness that i had to snake a wire out of to make it run. its the ignition power for the pcm. i just went ahead and bought another 94 harness.

brharris27370

Ok, if this thing is indeed a 96 or 97 LT1, can I just put the 94 harness back on and use it. I know the coil is also different on the OBD2 cars and I think I have an older coil but what about the ignition module and that crap. I really don't want to convert this thing to OBD2. I would rather go back if I can figure out how all this wiring goes back in this car. I am concerned about getting all the injectors wired back correctly. Most other stuff will only plug in one way.

brharris27370

Taking over someone elses screwup isn't fun I can tell you. This thing is in a hell of a shape and then just to have a stock car but it is a hardtop firebird with a decent gear so it should make a good track car.

shoebox

Yes, you can put the 94 harness in to work with the 94-95 computer. 94/95s had no BCM or crank sensor.

Injuneer

You really ought to figure out what year the engine is, first..........

And the fact that your 12-pin cable plugs into the ALDL connector doesn't mean whoever hacked the wiring in the car connected the light tan data wire to the correct pin. Not questioning your scanner or your cable, just suggesting that you make sure the data wire is in the right place.

You kinda have to follow up on the responses you get, or people will get the idea that you aren't really interested in the help they are trying to give you..... just an observation.