Hi fellas,

Having some trouble with my 84 today (stock Crossfire). It was a really hot day, and I was driving in heavy traffic. It ran like a top and idled without any issues. I stopped at the store for 15 min and when I went back out to start it, it just cranked. When I clicked the key, I didn't hear the fuel pump cycle. I took the injector cover off and put a rag under one injector - after about 2 seconds of cranking, I had a quarter-size drop of fuel on it.

I walked to work and came back after an hour and a half, and it started up without any issues. The fuel pump cycled very quietly when I clicked the key before starting it. It had a little trouble idling for a second at a stop light on my 2 mile ride home, but at speed it was fine. It idled fine in my garage, but when I shut it off and tried to restart it, it wouldn't fire up.

The fuel pump was replaced about 2 years ago, at 39k miles. I'm at 44k now. This was done by the previous owner though, so I'm not sure if it was a high quality part or just some cheap junk. The receipt doesn't mention the brand.

I haven't had a chance to test the relay yet, or look at the wires running to the fuel pump. My question is, would a bad relay cause the fuel pump not to cycle when I turn the key before starting the car?

Thanks in advance everyone! I'll update the thread once I test the relay this weekend.

 

Yes, if the relay was faulty the pump would get all wonky.

84s are notorious for fuel pressure issues. So start with the relay, then the pump then the filter.

The fact that you are not hearing the "BUZZZZZZ" when you flip the key is a indicator that the relay is the first place to check. You can see if your pump is getting power by disconnecting the harness near the gas filler neck. If you are getting power, then your relay is good.

 

Yeah, it is possible for relays to become intermittent before they fail completely. Heat can definitely be a factor in killing relays. Current flows best when cold, which would explain why the relay would work when cold. Once a relay closes, it will usually stays closed until it is shut off - when you turned the car off. When you went to restart it, there could have been enough resistance to keep the relay from closing - thus, no power to the fuel pump.

So in short: I'd bet its the relay.

 

Follow the advice you were given. Check the voltage and ground where the Fuel pump power wires feed the pump.

The wires are not hard to find under the rubber covers by the gas fill cap. On my 88 there are three wires, Red (+12 Vdc) to power the pump, the Purple wire goes to your gas gauge and the third wire is the ground.

When you disconnect the three wire harness you can try applying 12 volts to the red wire and ground thru the black wire. The pump should run when you make the connection. If not check the red and black wires for proper voltages.

Next I applied power to the output of the fuel relay and my pump ran fine. When I tried to get the relay to turn on it was having issues, it was a faulty relay.

I have never had an '84 with the Crossfire engine in it. Even though it sounds like a relay change your fuel filter as well.

Good Luck!

 

The relay is not the only means of getting power to the fuel pump on a 1984: there is also a switch in the oil pressure sensor (at the top back of the engine, by the distributor). The usual symptom of a bad relay is the engine cranks for a longer time (oil pressure comes up, closes the switch in the sensor, fuel pump runs, engine then starts and runs normally). There is something else going on, maybe heat related issue in the ignition??

 

 

Good Job there Paul!

Now you can go out and enjoy the benefits of your hard work! Enjoy your memorial Day weekend is style!


P.S. Do take a look for loose fitting wire connectors at the very end of the plenum where the oil pressure switch is located. Somebody made a bad connection trying to fix an Fuel related issue on my 1988 Coupe... Good Luck!

 

Good work. Easy Day.