1991 E36 320i Dirt Track race car, no start???
Very new here, and to the world of Bmw's, actually to the world of efi, and modernish auto electronics. Ok, as the title suggests, i am building a dirt track race car from a 1991 E36 320i sedan that i got given to me. First thing we did was to gut the car as much as possible, so everything came out, including about 35kg of wiring. To take the wiring out, we cut a wire, then made sure that the car still ran, then cut another wire, then made sure it still ran, etc... so I now have only the essential wiring for the engine, fuel pump etc. I have a new dash mounted between the trans tunnel, and the lower windscreen bar of my roll cage, with switches for the ignition, fuel pump cut off, and thermo fan, along with a few gauges and warning lights etc... Anyway, with all this installed, all i had to do was turn on the ignition switch, and the fuel switch, and press the starter button, and the car still ran fine, no dramas at all. Then some numb nut forgot to disconnect the battery, and did some welding on the car, (i am a professional boilermaker/welder by trade and have done this thousands of times and never blown a computer yet), now it won't start. I have checked all the relays and they are fine, i can power the fuel pump directly at the dash, bypassing the ecu, and the pump pumps, i have power to the coil packs with the ignition on, but don't seem to be getting a spark signal to the coils, and the computer won't allow the fuel pump to work when i hit the starter button as it used to, unless i power the fuel pump directly as i said before. So, i am of the assumption that i have blown my ecu. I got a spare ecu off ebay, but when it turned up it had a different number than what the add said, and it still won't start the car. the ecu number from the original is 0 261 200 403, can i install a performance chip to fix the problem, or do i still need to replace the ecu? Also are there any other numbered ecu's that will work in my car as this number seems to be a hard one to find?
thankyou very much in advance for any help offered,