JBT

I have an GMPP ls3 crate engine with Controller kit that wont start. I have found one problem and that is that the fuel pump relay is not working.

The dk green/white wire (fuel relay singal) from the ECU is giving me varying output: it reads 12 V with relay disconnected, and drops to 0 V when a known "good" relay is connected. Is it possible I have a bad transistor inside the ECU? ...OR is there a sensor that contributes to the voltage dropout if the reading is incorrect?

I have also tried to run the fuel pump on external circuit and it sputteres a few times as if it is trying to start, but does not actually continue to run.

Any ideas?

rotor vs. piston

iTrader: (3)

My guess is you have 12v on both sides of the circuit to trip the relay. The ECU provides 12v positive and you need to ground the other side.

JBT

There is ground on the other side of the coil.