Fuel pump woes...

[LTb1ow]

Long story.

Got a new Walbro bout 4 weeks ago with the Whiplash group purchase. Installed the pump by dropping the tank, pump primed, engine ran. No problems at all. Went to school for a week, came home that holiday weekend, and while driving car just shut off.

Check fuses, the relay, all checked out. Pump would not prime or anything. OK, bad pump.

Whiplash sent me a new pump, which I installed today. Only took me an hour and a half, I got mad skillz. Got it back in, pump primed, car starts and idles.

Drive down my block and maybe 300 ft down the next road, car dies. Adam and I proceed to start to push the car, and while taking a break, he gets the idea to maybe smack the tank.

Hits the tank, pump now primes, we continue on to the JSFBOA meet.

On the way home, after maybe 2 minutes of driving, not even out of the lot, car dies. Try to smack the tank again, some luck. Car would prime, but die after a minute of running. Pump woiuld then not prime.

After a few minutes of me thinking to myself why the **** I bother with this damn car, I go to prime it, and it does it with no bangs to the tank. Test it a bit, and figure what the hell, lets go.

Makes it all the way home, not a single problem.

Cliff notes:

Two brand new walbro pumps, same symptoms. No fuse blown, relay checks out, battery was just taken off charger. Stock fuel pump ran flawless for 75k miles.

Ideas?

did you get just the pump or the hot wire kit?

[LTb1ow]

Just the pump.

[BonzoHansen]

Bad ground. Damaged connector. Pinched line.

[LTb1ow]

Bad ground how?

Two "brand new" damaged connectors?

Pinched line causes the pump to work whenever it feels like?

[BonzoHansen]

Just throwing out ideas.

Your harness. You maybe damaged the harness side? The pump circuit has to ground somewhere. I'm not familiar with your car, but is there a ground wire somewhere back there that is loose or something?

[LTb1ow]

To drop the tank you only unplug the fuel tank harness. Did that, and did not screw with anything else electrical wise. Plugged in the supplied harness that interfaces between the stock wire and the walbro. Made sure it was nice and snug. Re installed.

Just primed it and it started right up. WTF.

[BigAls87Z28]

Yeah, that was an adventure.
Im stuck on it being a electrical problem. Could be something you didnt touch.
If itw as abad pump, it would just be crapped out all the time
I say throw the stocker back in, see what happens. If it happens tot he stocker, then something happend that you didnt touch....or maybe you did.

[JL8Jeff]

When you say it won't prime do you mean you turn the key and the pump is not running at all? Or it's running but not picking up fuel? Isn't there an inertia switch somewhere that is supposed to shut off the pump in an accident? You may be having issues with that. I'm not sure it's a pump problem vs power getting to the pump consistantly. It sounds like an electrical issue.

[LTb1ow]

Yea prime is just switching the key on.

I can force the pump on via a hot lead in the engine bay, so I was going to do that for a while and maybe monitor voltage going into the pump harness.

With the key off, the injectors should all be closed correct? I don't wanna flood a cylinder.

[Whiplash Performance]

Originally Posted by LTs1ow

Yea prime is just switching the key on.

I can force the pump on via a hot lead in the engine bay, so I was going to do that for a while and maybe monitor voltage going into the pump harness.

With the key off, the injectors should all be closed correct? I don't wanna flood a cylinder.

Yeah with the key off the injectors should all be closed.
The computer commands the injectors to open.
So the pump works if you just connect it to a power source?
Do you have a volt meter to see the voltage going to the pump?

[LTb1ow]

Ok more to add.


Went to move the car this morning, backed it down the driveway, and it died. I then used the fuel system test wire and hooked that up. Pump came right on, and I started the car. Un hooked the lead, car continued to run. Drove the car all day, no problems as of yet.

Weird.

[Whiplash Performance]

Originally Posted by LTs1ow

Ok more to add.


Went to move the car this morning, backed it down the driveway, and it died. I then used the fuel system test wire and hooked that up. Pump came right on, and I started the car. Un hooked the lead, car continued to run. Drove the car all day, no problems as of yet.

Weird.

Corrosion on any of the terminals?

[S.J.SLEEPER]

bad fuel pump relay?

[Whiplash Performance]

Originally Posted by S.J.SLEEPER

bad fuel pump relay?

Good call.
Maybe, since the new pump draws more current, the relay cant handle the extra load.

[S.J.SLEEPER]

Originally Posted by Whiplash Performance

Good call.
Maybe, since the new pump draws more current, the relay cant handle the extra load.

thats what i thought,
he should install the hot wire kit anyway,gauge of stock wiring ftl .

[LTb1ow]

I will try that when I get some money.

[S.J.SLEEPER]

Originally Posted by LTs1ow

I will try that when I get some money.

get the part # off of it or any other #'s
i might have one. you can have it if i got the right one

[LTb1ow]

The hotwire kit?

Should be for a 95 LT1. I know there are a few different variants out there.

[Tru2Chevy]

Originally Posted by LTs1ow

The hotwire kit?

Should be for a 95 LT1. I know there are a few different variants out there.

No, although the hotwire kit is recommended, the last few posts are talking about swapping to a new FP relay to eliminate the possibility that you have a problematic one.

- Justin

[transmaro93]

hey matt... they only make on hotwire kit for lt1's.... well they make one for f-bodies and one for b bodies... anyway... the one i got direct from racetronix has the part number FPWH-003 ....

[LTb1ow]

Yea, told the parents to get it for me as a Bday gift. It is hopefully the stock wiring at fault.

[transmaro93]

yea im still puting money some kind of electrical problem... get it off racetronix website its hte cheapest i found... and only took like 4 days to come standard shipping from canada.... i got their injectors too.. pretty niceeeee

[LTb1ow]

Nitrous outlet has em for 59 bucks.

[sweetbmxrider]

i got mine for $55 shipped