R33 No Start...fuel Pump Earth?

[roadworia]

hey guys....been having a bit of an issue with my r33. the car randomly will not prime the fuel pump... checked power to pump-ok. ...checked relay operation- ok found when i direct the pump it runs fine. also checked sender unit/fuel pump intank harness-ok

what i did find was on the harness side of relay ie terminal 3 has battery voltage....5 has continuity to ground(no high resistance)...the switching (positive) terminal has around 5v and the grounding side has 0.4v coming through it...is that normal?

this was all checked in the non priming status...

i have also checked ecu pin out 18 (fuel pump relay) and it has almost no resistance to ground...

where do i go from here?? any help would be much appreciated..

cheers

Roy

[GTScotT]

sounds like the relay is shot and cant withstand the current draw.

wire in a new relay triggered off the stock relay and see if that works. new relay should get power direct from 12v not old relay.

also may want to try just swap in a mates stock relay to see if that works, if you have any R33 mates that is lol (if your in bankstown i could even let you try mine)

[roadworia]

thanks mate...question: wouldnt that be same as putting a new relay on it?? tried new relay already...hasnt fixed it..

Edited January 17, 2010 by roadworia

[GTScotT]

ahh i see, interesting then.

in that case perhaps a dry joint somewhere. try wire in whole new relay triggered off the original. new wiring from pump to new relay and new relay triggered off old pump.

should fix the problem for sure

[roadworia]

ok...so i found that the relay switching circuit is not being grounded....when it randomly does turn on, the car starts and runs fine...does this mean its an immobiliser fault?

[rbscreamer]

ok...so i found that the relay switching circuit is not being grounded....when it randomly does turn on, the car starts and runs fine...does this mean its an immobiliser fault?

Mine just did this today, car was running fine last week and now car doesn't start. Call auto electrcian and he fix it. Found that there was no earth to fuel pump. What the hell. He cut the earth wire to fuel pump and got earth from another wire for now. His coming back next week to find the cause. Thinking of just running direct feed to the pump. You any one in Sydney who can do this.