2stroke1971

1985 FB, 12a

At the end (I hope) of a long road troubleshooting a fuel problem.
Car would cut out, lack of fuel....once in a while, then got more frequent...would just up and work after sitting a while. Would always run on ether or if you splashed gas in carb.
Carb is rebuilt, and I double checked the floats and inlet valves recently.

Dropped tank, checked pickup, new fuel filter, new lines, etc. Most recently I jumped the fuel pump relay so that it would run with ignition on.

At that point, I could hear the pump run with the key on....sort of vibrating against the guard I guess. Previously of course, the pump would only run with the engine on, and I cnould not hear it over the engine.

I took it down the street today and it died. I pulled off, and of course after turning the key off and back on, I hear nothing from the pump. 15 minutes later, I key on and the pump runs. It starts, then dies....key back on, and no pump. Pulled it back up the street with a strap and after sitting for an hour of course, the pump is buzzing nicely.
Its a handy thing, being able to hear the pump or not.
SO....
The pump is cutting out now after just a few minutes.....bad pump right? I know most high pressure FI units tend to just die, but I guess a pump could fail in an intermittant manner as well.....

Im just gonna go with a new pump because I think thats the last piece of the puzzle. Dont have the $$$ for the Holley and regulator that everyone seems to recommend. Id be happy with a 4 pound unit that actually works and Ive got a line on several.

So heres a dumb question. Has anyone ever thought of relocating the fuel pump to under the hood? I mean where it's at is a total pain in the ****, the pump thats in there now does not fit right...(its not the stock unit) and it was a challenge to get the fuel lines snaked in and out of the guard down there. If Ive got to go with a new pump, why not just put it under the hood, or would there be some issue pumping that far away from the pickup?

Thanks in advance for any comments!!

Jeff20B

iTrader: (13)

The electric pump must be under the tank for gravity-feed to take place.

If you had a V8 or an air cooled VW with a mechanical fuel pump, those can be mounted far away from the tank on the engine.

Electric pumps can't pull fuel down a line very well. Mechnical pumps can. That's the difference.

So to answer your question, you shouldn't install a fuel pump in your engine bay, unless you do something stupid like put a V8 in it. But even then, I'd keep the fuel pump in the stock location. It's pretty easy to deal with under there.

Oh and I don't use Holley fuel pumps. They seem to be problematic.

elwood

iTrader: (1)

Ever hear people talking about "vapor lock" on any car built in the last 30 years? Probably not. Whenever a pump has to suck fuel against any sort of resistance, it can lower the boiling point of the fuel so much that it vaporizes in the line leading from the tank to the pump. It was a common issue on cars with the old mechanical pumps in the engine bay.

Keep the pump in the original location.

2stroke1971

THought I would update this. I bought a Carter pump and so far so good. The pump's instructions advised not placing it more than 24 inches above the bottom of the tank. I put it in the normal place, it fits alot better than the one that was in there. I made a nice cushioned wrap around it, and it's nice an snugly nestled under the guard, and all the lines are tucked up out of sight....(with the last pump, part of the lines were sort of exposed.)
Drove it about 10 miles to pick up some pizza for the test drive, and so far so good.
Now on to the laundry list of other reasons I should not be driving it alot yet.....