Fuel Pump

[mhagedon]

I hope this is the right place to post this question..

I was driving down the interstate last night and my truck cut out a few times at about 70 and than kept running fine for a half mile when it started cuttting out real bad until it died and wouldn't start.

It was running excellent untill it's last half mile. The engine is getting spark and turns over fine, but when i turn the key to the run pos. i don't hear the fuel pump prime.

I've had a coule fuel pumps go out in the past on different cars and it was always a gradual thing. (Hard starting, hesitation that got worse and worse)

So i'm stumped (which isn't hard to do)

 

[mhagedon]

Ok, just went outside. I'm leaking fuel from the top of the tank. So i'm guessing the pump is bad. This is my third '88 now and i've never had this happen...

 

[RobbieD]

Well, you're off to a good start, if you know that you've got ignition spark, and know that you can't hear the pump.

Might want to check for power to the pump coming out of the inertia switch, which is on the passenger side lower firewall, inside the cab. If you've got power out (think it'll be a Black/Pink wire), then you need to get look at your pump. I believe that you might have two pumps on an '88, one in tank and a second inside the driver's frame rail.

Welcome aboard, and good luck with it.

 

[RobbieD]

Maybe the pump is OK and you've got fuel line issues. If your bed bolts are not in real bad shape, I'd suggest pulling the bed off to best get to everything.

 

[mhagedon]

I checked the inertia switch already since the heater core has been leaking on it for.. a long time lol. I'll check to see if it has power though.

I think my only option is to pull the bed and see what i've got. Hopefully it's a pretty straightforward fix!

Thanks alot man!

 

[RobbieD]

Yep, hope it's something simple, too. Good luck, man, and let us know how it turns out.

 

[mhagedon]

Put a test light on the wires going to the inertia switch and i'm not getting any power from either wire. Tested while cycling the key off and on. (Don't know which one's supposed to be hot)

I'm going to try to run a jumper wire to the not-hot wire and see what happens. Unless that's not a good idea...

I'm trying to get off easy here! lol

 

[MAKG]

Time for a systematic voltage drop test. Probe the ENTIRE fuel pump circuit from battery post to battery post. The location of the voltage drop is where the fault lies. It almost certainly is NOT the pump.

The fuel leak is probably unrelated. Odds are, the vapor line grommet rotted out or somesuch. Happens all the time. Feel the top of the tank, and it will probably be obvious what's going on.

 

[mhagedon]

I hooked the pink wire with a black stripe to the positive terminal on the battery. The pumps are fine. It turns over and even runs on ether but refuses to fire without . I just want to get this thing running and i'm becoming frustrated. I don't know where to check for fuel pressure but i'm sure i'm getting enough for a sputter or two. But... nothing

Maybe my injectors aren't getting power either. I'm totally lost and am starting to remember why i sold my last one!

Any help would be greatly appriciated but i think i'm on my own with this one!

 

[mhagedon]

The ground wire for the relays going to the battery terminal had a bad connection. I replaced both battery terminals and the problem was solved. Thanks alot for the help guys!

 

[RobbieD]

Good to hear that you got it sorted out, and thanks for letting us know what it was. You did good!