I have a 92 camaro that used to be a throttle body injection. I have changed it over to a tuned port injection that is controlled by Mega Squirt. So I have deleted the whole ECM. I have figured out how to wire the pump to the new Mega Squirt usine the factory relay.

I do still have some questions though.

1. for the fuel pump relay I have a thick orange wire that is carrying a 12 volt continous power source, same with a black wire for ground. I can energize the coil by giving the green and white wire 12 volts+. Then after I have the relay energized I have a 12volt source at the grey wire. There is a red wire that also comes from the realy that goes to the fuel pump prime connector. I would like to know what each of these wires were originally intended to do/control? I know that the grey wire splits off and goes to the oil pressure unit for sensing pressure, so should I just ground that wire or clip it and the oil sending unit?

2. I went through the schematics charts for my car and can not figure out how the insturment cluster recieved a reading for coolant temp.

 

Orange - +12v from battery
Grey - +12v to the FP after the relay is energized
BLk/wht - ground
Green/wht - controlled +12v from ECM
Red... got me (maybe goes to the ALCL 'G' terminal for fuel pump test ?)

The temp gauge is just a wire (green) from the temp sender to the gauge. THe gauge gets power from the same circuit as the other gauges.

 

Right, but there were originally a grey and green/white strip wires going into the ECM. The grey goes from the pump, to the engine bay splits, then to the relay, oil pressure sending unit, and ECM. What did the computer do with the grey wire?

 

The gray wire goes to pin "E13" at the ECM and this is for the fuel pump voltage monitor. It also goes to pin "C" of the fuel pump/oil pressure switch, pin "E" of the fuel pump relay, and the fuel pump itself. The red wire goes to the fuel pump test terminal in the engine bay. As for the coolant temp, that is simple. The dark green wire goes from the coolant temp sender to pin "C" of connector C1 on the ignition switch and then goes to pin "C4" on the instrument cluster.

 

I seem to have just ran into the Grey wire while installing Gen 7. What should be done with it?