To make a long story short, my car stalled like it ran out of gas. Had it towed to my garage, and looked it over. I checked both fuses under the dash (FP - Inj, and INJ I believe). Both were fine.

When I turn the key, the car cranks and has spark, but the injectors barely drip fuel. Also I cannot hear the fuel pump "Priming" or pumping at all.

My first step was to replace the fuel pump in the tank. Got it all back together, and still the same problem. Injectors barely drip, and no "priming" from the pump.

Next I read through the Chiltons manuel, and it says there's a fuel pump relay. I think it's the one underhood, on the driver's side of the firewall. It has 5 wires - red, orange, tan, black, and green. The book shows 4 wires, no green.

How do I go about testing the relay? Is there anything else that could be stopping the fuel pump from going?

1988 Firebird Formula 5.0L TBI

Thanks for any input ...

KZad

 

personally I'd go check for voltage to the pump first, your relay may be fine but no voltage is getting to the pump. Check that first and work back. Then test the relay by connecting a computer-safe test light to the pin that supplies power to the relay when cranking. If power is there then test the pin that supplies power to the pump.

See you may have power to the relay, but the contacts may not be closing.

Hope this helps.

 

The TBI fuel pump circuit looks like this:



I would start from the front of the car and work back. It is easiest up front. For Firebirds, the fuel pump relay fuse is along the vertical radiator support (IIRC) in a black weatherpack case. If that fuse blows, the fuel pump relay will recieve no power, thus no power to the pump.

Then check the relay and work your way back.

 

or go to the parts store buy the relay, probly 10 bucks, and put it in there.... if it does the same thing, put your old one back in the car, and return the new one

 

I followed the advise of montesa311, only because it was the easiest, and possibly a free fix. No dice. New relay, same problem.

"For Firebirds, the fuel pump relay fuse is along the vertical radiator support (IIRC) in a black weatherpack case."

Do you have any pictures, or a better description of where this fuse is located? Driver or passenger side? I don't recall seeing any fuses near the radiator, and I'd like to check this next.

I'm not sure I can follow those schematics. Are there any "directions for dummies" that you can give me? I am going to get my hands on a volt meter. What else will I need?

Thanks,

KZad

 

Sorry, no picture. Should be near the battery/radiator support in a fuse holder.

If the relay was a no-go, I'm guessing this fuse is blown.

 

Alright, a friend of mine stopped by with his volt meter last night. We found out a few things, and I dont think it looks good ...

We have power all the way back to the connection to the tank. We also have a good ground at that connector.

We decided to hardwire the fuel pump, to see if we could get it to prime. We stuck a wire into the ground terminal of the connector, and established a good ground. We then stuck a long wire into the power side of the connector and tapped it on the battery.

If we're thinking correctly, this should cause the fuel pump to prime. It didn't. When the power wire was touched to the battery we heard a click, and then another more faint click when the wire (and power) was removed. The click is similar to a snapple bottle cap, but in a deeper tone.

Now what can the problem be? Is it possible that the sending unit is not letting any/enough power get to the fuel pump? Does the wiring go through the sending unit?

Any opinions are appreciated.

Thanks,

KZad

 

Are you sure you got the connections on the pump good and tight?

Sounds like either a loose or corroded connection or a bad pump.

 

Turns out the the pump I put in was bad. I took the fuel pump and sending unit out of the tank again last night and tested with the volt meter, and a hard wire right to the battery.

Put a good fuel pump in, and all works fine. The car was running last night.

Thanks everyone for your help.

KZad