I'm trying to get my 89 Camaro 2.8 running so I can get it sold. Its been having trouble for a while and I think that it is something in the wiring. I'm getting power to the pump, but the pump is not kicking on. The pump and filter are brand new, wiring looks good. With the key on I'm getting ~10V to the pump and with the motor turning over I'm getting ~6V which doesn't seem right. I'm down to tracing wiring, where does the ground for the relay go to? I'm thinking that I'm getting a bad ground. Its not the oil pressure bypass either, I have cranked the car for several seconds for the oil pressure to build up and nothing.

 

Time to break out the multimeter and start testing wires and voltages.
This diagram will help: http://www.austinthirdgen.org/mkport...ine_wiring.gif
More diagrams here: http://www.austinthirdgen.org/index.php?pid=19

If you suspect the grounding black/white wire, put a voltmeter on it and measure voltage with the relay actuated. If you see more than a few millivolts, you might have a bad ground.
However, since you say that you have voltage to the pump, I would think that the relay actuates correctly. Though, it might be old and oxidized/burnt inside and could be causing the voltage drop to the pump.
So I'd check that next. I'd measure the voltage on the orange wire going INTO the relay and also voltage on the tan/white wire coming OUT of the relay, with the pump running. Any voltage difference?

Lou

 

Where does the ground go? That's what I am trying to find on the car but can't locate where it goes to. I have all of the wiring diagrams and everything.

 

The engine harness grounds usually go to the back of the block or head. The actual black/white wires are spliced inside the harness. Depending on the local weather conditions, that splice could be corroded badly or it could be still pristine. I've seen both.

Lou

 

I've gone through the wires again and I'm not finding anything wrong. I'm getting 10.5 V to the pump and at the relay. Is there a way to hotwire the pump? I'm tired of chasing wires and want the car out of here.

I am getting power at the pump but no prime. Bad ECM or relay?

 

Does your fuel gauge work ?

( use a spare battery or make very long jumpers! ) Locate the fuel sending unit plug and disconnect it from under the car. ( located near the rear end pumpkin. ) I suggest this spot because it's close to the pump and your not cutting into any wires. Just disconnect, test, then re-connect the plug.

Run a "jumper wire" from the "+" side of the battery to the TAN wire on the fuel sending unit plug. Run another jumper wire from the "-" side of the battery to the BLACK wire on the plug.

If the fuel pump doesn't work than there is either a wiring problem ( corrosion / broken conncetor) on the sending unit..... or the pump is dead. Your basically bench testing the pump this way as there is no relay/ecm to deal with,..... give the pump power and ground and see if it works.

If the pump turns on; start working your way to the front of the car by checking the wires, then relay, then Power/fuseable links, all Grounds back to the body and battery.

At the Pump relay the wires appear to be :

Red to ALCL under dash
Tan/White Power OUT from relay to Pump/ECM
Green/White Fuel Pump control from ECM
Black/White Ground
Orange Hot at all times from in-line fuse.

Good luck !