I have a 98 Tahoe that had a lot of aftermarket stuff on it (alarm, sound system, etc) at one time, but it was all removed before we bought it. Of course it didn't run because of the passlock system when the previous owner removed all the bypass equipment. Anyway, we have solved the "tamper mode" issue and are down to a fuel/starting issue and I'm at a loss where to go from here. We have 12v coming in on 87 to the fuel pump relay and if we tap the relay it will trip and start the pump, but it will not shut off. If we crank it we loose all fuel pressure and the relay trips back out. On 85 we only have 6.9v. I believe this is the pin the heats the coil inside the relay to trip it. Not enough voltage to cause it to trip, but when we tap it, it trips. If we jumper 87 & 30 the fuel pump runs and we can start and run the vehicle. We can also jump orange to gray at the oil pressure switch and the pump runs. So I have come to the conclusion that I have an issue on the green/white wire that comes to pin 85 on the relay for one. Everything I have read says this wire comes from the VCM, but I can't find the VCM any where. Can any one give me some input or a wiring diagram or something? Thanks.