I have a guy calling me needing some help. He's got a 1994 Caprice 5.7L Iron headed engine installed in his 69 Camaro, He bought a painless wire harness, LT4 knock module, and LT4 Kock sensor.

The PCM has not been modifeid.

It's throwing an ESC code of somesort after first minute of operation. He says its down on power when the light comes on. His scan tool didn't give a specific DTC #, but hes going to try to get it.

I understand the caprice engines had two knock sensors, his painless harness only has 1 sensor.

What are the options at this point?

I was thinking about programming his PCM with a F-Body calibration, and copying the iron headed fuel/spark tables to the F-Body calibration.

Anyone know any other ways around it? Maybe one without reprogramming?

 

Let's hope you meant knock sensor........

There is no such thing as an LT4 knock sensor. 96/97 LT1's and LT4's all used the same sensor. But the 96/97 sensor will not work correctly with the LT1 OBD-I PCM, since the resistance is not correct. Not sure if the B-Body OBD-I PCM was compatible with the high resistance sensor, but I doubt it.

 

i belive theres 3 knock modules that go in computer as far as options not sure of part numbers right off but i had to have the one programmed out of my comp cause i was gettin same codes

 

There is a single knock module in the 1994-97 LT1 PCM's. The LT4 knock module is compatible with all years and will not cause any codes.

 

I used a painless harness in my 68 conversion. You need to get the knock sensor (screws into bottom of block) that matches the PCM. The b-body PCM needs 2 knock sensor readings. You can retain the b body tuning, you just have to add another knock sensor. This is very easy, just get another sensor and wiring pigtail. Install the sensor on the other side of the block and splice the new pigtail into the other knock sensor wiring. I went though this with my swap and it did the same thing, it ran great after fixing it! THe reason it seems to be down on power is that the computer is sensing a "knock", probably a code 43 and it is retarding timing.

Read this thread and it will give you good info: http://web.camaross.com/forums/showthread.php?t=526123

 

My main concern was the LT4 Kock Module in use with 2 knock sensors. He needs to use the knock sensors for whatever the PCM is from correct?

 

I have (had) the iron head engine with a single knock sensor with the PCM reprogrammed for the single knock sensor. Basically the FBody PCM and wiring with the iron heads. Program timing/fuel accordingly.