i need desperate help tonight about my fuel pump

[jptaylor2]

im getting a code 54 and i have replaced the fuel pump relay. the engine just spins with no fuel. my pump never energizes. where do i need to check the voltage. please be specific as im not too good with the electronics. ill be outside trying until god knows when trying to get her running for tomorrow. please help

jptaylor

[WS6 VERT]

Sorry about your troubles, bro.

Since it is setting a code 54, its probably safe to say your fuel pump is OK, since the code 54 indicates there is no voltage from the pump relay.

You will need to remove the relay, and check for this:

You should have constant 12V on the ORANGE wire, with the key on and off.
You should have a constant ground on the Black/White wire.
You should have 12V for 2 seconds when you first turn the key on, and while cranking.

[jptaylor2]

im stumped...

ive got power everywhere im supposed to going into and coming out of the relay. what is the thing right in front of the tank and right above the rear differential. it looks like another relay with a three wire weatherpack going into it. i was looking for a place to test for current back close to the pump and saw this. it looks like the pump wires run to this thing. please help.

jp

[SportCoupe]

Just jumper out the two big wires at the relay. Not the black one though. The pump should run. If it does then change the relay.

Are you sure you have the right relay? They are all close together on older F-bods. Swap out with another relay if you are low on cash just to try.

The 3 wire thing back by the tank is just a wire feedthru, not a relay. The is a disconnect for the fuel pump and fuel sending unit. Yes you could check for voltage there but it is harder to get to then the relay.

[jptaylor2]

john ive already changed the relay. i tried to jump out the tan and white wire with the constant 12 orange wire. is this what your talking about or am i jumping the wrong wires. i tested the relay connections and ive got a 12 constant and a constant ground. also the tan and white wire energizes for two secs when i turn the key. the relay clicks LOUDLY on when i turn the key and LOUDLY off when i turn it back. this has got me just baffled. on a side point though i did make a rear strut tower brace last week and the difference is unreal. the car doesnt rattle nearly as bad anymore and it feels very planted in the sharp turns now. granted ive got a t-top car and it probably wont make as much diffenence on a solid car but i was amazed!!!

[SportCoupe]

OK JP your relay sounds good. Must have lost the voltage somewhere between the relay and the pump.

Check for 12 volts at the rear connector (in front of the rear axle) tan wire. It should have 12 volts for 2 seconds with key on. Try and use a test light instead of a multimeter as it will check for good curent as well.

Remember one strand of wire will indicate 12 volts but will not light a light bulb.

If you have power at the rear connector by the tank then you have a bad ground or bad pump, either way the tanks coming out.....

[jptaylor2]

john i hate to be so specific and needy but im having a hard time finding the rear wire your talking about. ive found the one i mentioned earlier but you said that was not the right one. can you help me narrow down my search. thanks

jptaylor

[WS6 VERT]

That three wire plug that you saw at the back of your car is the rear passthrough to the tank. Pull it apart and check for voltage on the Tan/white wire during cranking on the BODY side. If you do not have voltage there, then you have a break in the wire between the relay and the back of the car.

[mrr23]

might be the fuel pump fuse blown. located either by the battery or the opposite side. in a samll black case just the size of a fuse.

[SportCoupe]

Originally posted by mrr23:
might be the fuel pump fuse blown. located either by the battery or the opposite side. in a samll black case just the size of a fuse.Can't be, he has power to the fuel pump relay. Good call though.

[jptaylor2]

my three wire pass through thingee has a green wire a green/black stripe wire and a black wire?? what gives.

jptaylor

[mrr23]

Originally posted by Millican:
</font><blockquote>quote:</font><hr />Originally posted by mrr23:
might be the fuel pump fuse blown. located either by the battery or the opposite side. in a samll black case just the size of a fuse.Can't be, he has power to the fuel pump relay. Good call though.</font>[/QUOTE]your right. after looking at the wiring diagram it's before the relay. i thought it was after. here's a thought how about jumping the terminal in the ALDL port with a 12 volt source. that way there is constant power to the pump. then test the wires. should be the green/black stripe. the green one is to the fuel sender. the ngo test the wires at the tank. you'll find out that way for sure. the fuel pump pin in the ALDL is the far left lower hole. i used it to diagnose the problem on mine. when you connect power to the terminal, the pump will run continuously.