I am currently starting a full rebuild of my car, and tearing everything out of the engine compartment. While doing this I've discovered That the wiring in the engine bay is fairly brittle in places, so I was going to switch it over to a 94+ style. My reasons for the switch include wanting to change to MAP instead of SD, the ability to go with the less sensitive LT4 knock sensor, and easier reprogramming (burning EEPROM's is a pain, plus finding a pc with a serial port is getting harder every day ).

Anyways, from my understanding all I need is to switch the ECM and wiring, and add a MAF and later knock sensor. Is this correct, and is there really any reason not to do it? Also, what wiring harness should I go with (used, painless wiring, etc)?

 

Trying to picture the differences..It will not be a plug and play changeover. Would be easier with a '94 engine from a donor...There are lots of physical sensor and connector differences. Probably enough to make it a very time consuming and costly conversion. If you use a '94 PCM and harness, the OPTI should hook up, but you will need a new ICM as the '93 connections are different, the Tach drive for a 94 is from the PCM not the ICM so wiring to dash needs work, pretty sure the '93 tach will not work with '94 signals from PCM, the '94 PCM requires different VSS signal from the tail-shaft, the '93 speedometer will work with old VSS but not the new speedo signal from the PCM. I think the batch fire injector setup in the '93 will convert to sequential with new harness/PCM, '94 and '93 IAC and connector are not physically the same , not sure how the IAC control for the IAC will work if at all . '93 injectors flows are different than '94's. Are you an A4 or M6 if A4 you will need a tune work out running a 4L60 on a 4L60E PCM. Since you have EGR and air deleted the harness mismatches will not be a problem. Not sure if MAP, TPS sensors supply the same voltage, however I think physical TPS harness connector is different and you need old TB linkage to control the tranny shifting. KS and circuitry is different as '94 has KM in the PCM.

 

I don't think you understand that the LT4 part is the "knock module", not the "knock sensor". The 93 and 94 knock sensors are the same. The LT4 knock module is a module in the PCM. And is not "less sensitive"... it's got revised noise filtration to eliminate the noise signature of the Crane Gold full roller rockers used in the LT4's. Some people attribute near miraculous properties to the LT4KM, but most of it is hype.

 

Yeah I misspoke when I called it the knock sensor, but I'm planning on going with the pro-mag roller rockers and bbk headers, and I don't want to lose power because of the 93 standard module. It was my understanding that it can't be desensitized in the 93's, but then it's been about 7 years since I've really been involved with the car and LT1s in general, so I could be wrong.

 

There is no "module" ion a 93.... that's the problem. The knock sensor can be "desensitized" with a simple resistor circuit.