I currently swapped a ls1 and t56 into my old lt1 a4 car. Im having a problem with the car not starting. Turn the key and nothing. All the gauges and everything works like normal fuel pump primes and ect. I havent touched any of the old a4 under console shifter wiring. Im guess I need to bypass the neutral saftey switch to get it to start. Any suggestions would be good. Anyone have a picture of the under console harness that the plugs are labeled?

 

There is a flat 6-pin connector that used to connect to the A4 shifter assembly. The brown and yellow 12 guage wires (the biggest ones) go to the clutch switch (the black one). This is your park/neutral lockout. I'm not sure if the LT1 interior harness will work with the LS1 engine harness though.

 

Got it running by hooking up the a4 shifter for test firing purposes. The only prob is the tach is off the harness was done by speartech.

 

Did you have the PCM flashed for the M6. If not, the tach is off because the T56 VSS puts out 16 pulses per output shaft revolution, and the 4L60E puts out 40 pulses. Is your speedo reading less than 1/2 of actual speed?

You need to have the PCM reflashed to an M6 program. Then you will have to address the M6 wiring, which will include the safety switch on the clutch, that will prevent the car from starting unless the clutch is depressed. It will also allow the reverse lockout on the T56 to function. Isn't is a bit hard to push the shift lever over into the "reverse" slot?

 

The pcm is outta the m6 ls1 car. Everything should be good but the rpms just dont see right. Havent got to drive it yet.

 

The ls1 uses 1 signal per revolution where the lt1 uses 2. Ur tach is off by two your computer needs to be flashed. T56 to a4 has nothing to do with tach. They sell tach conversion harness with a module that duplicates the signal but its to expensive. Find a good tuner in the area tell him whats up he can do it no problem for cheaper than that.

In that flat 6 pin connector. The green and brown is for back up lights that needs to be ran to ur back up switch to get the lights working and the park/neutral saftey wires need to be wired together black and orange I think but don't quote me on it.