fuel pump or relay?

[benoit454]

Ok my 88 has got another issue now. I swapped my old man batteries when I pulled my trans and such, and his battery sucks, so I charge it up yesterday to start the truck, been sitting for about 2-3 weeks w/o running. Ran fine before. I charge, it cranks, then fires, runs a few seconds and dies. Then it just cranks and cranks won't fire. Dump some gas in, it'll run for a few and die, like as long as the gas is in it it runs, once burnt off it dies.

Well the fuel pump fuse under the relay cover on the firewall has NO power, key on or off. The junction block has direct battery power at all times.

Sounds like the relay to me, what do you guys think?

[Restrorob]

My 97 has the fuse before the relay, So if you have no power on the FP fuse you have no power to the relay. You could run a jumper wire to the fuse only to see if the pump runs, Then sort out your wire issue. But be careful pushing anything in the panel that can spread the fuse connectors apart....

[benoit454]

alright done tried that, when I give power to the fuse the pump comes on and runs, and it's pushing fuel. I had it unhooked at the filter and it shot about 3 feet just a split second hooked up.

Truck still won't run that way should it? I would think with the FP running it would start. If I dump gas in it it will. but only for a second. I dumped gas in it and hooked my jumper wire up and tried it, it ran until the gas I dumped in burned off, like 1-2 seconds, then died and won't restart.

[Restrorob]

Originally Posted by benoit454

when I give power to the fuse the pump comes on and runs, and it's pushing fuel.

Sorry Chris, But that's about all I can give you..... My rig uses the in-tank pump and relay wiring system but has a carb on it.

Your FP fuse is on switched power (gets power when key is on) so there must be a bad/pulled loose connection pinched wire or something causing the power loss, This may be causing the ECU to stop sending signal to the injectors ?

Maybe one of the EFI gurus will stick their head in soon.....

[benoit454]

it's ok I appreciate and thank you for the help.

It seems to be down to the injectors, or the tbi maybe press. reg. or something?

I get fuel all the way to the tbi unit itself(took the in line off the back and turned the key on)

Now my FP is working as it should, I hit the key and it comes on for a couple seconds and pushes fuel as it should.

Maybe I just didn't hear it yesterday, but that fuse didn't have power yesterday for sure.
I haven't checked it today but since I hear the FP when I turn on the key and it pushes fuel out all seems to be working. It just doesn't get gas to the intake.

So i guess my next question would by how can I check to see if the injectors are getting power? I only have a test light, but could maybe borrow a ohm meter/voltage tester.

[Restrorob]

Just throwing things around, Have you checked for any blown fuses in the dash panel ?

On the back of my engine (between the engine and firewall) is a big wire harness, Any chance you had a wire drop down between the engine and trans and get pinched ?

[benoit454]

checked al the fuses last thing tonight, all are good, also wires aint pinched the trans is still out.

[FTW66]

My 88 did the same thing on super bowl sunday. Gas all the way to the tbi, nothing at the injectors. I swapped out the Ignition Control Moduel, which powers the injectors and it fired right up!

[benoit454]

mine fixed itself, just worked one day, and didn't the day before.

[Boog]

You can bet it will do it again though.