Mechanics

FUEL PUMP ELECTRIC

1973 Pontiac Firebird • V8 2WD Automatic • 45,000 miles

Hello I have a 73 firebird with a 400 big block I think the fuel pump is going out on it cuz it starts and runs fine but when I drive it for 2-3 miles it sputter like it starving for fuel (maybe vapor lock) but when I park it in the driveway and let it run it dies in about 2 minutes so I was going to replace my mechanical pump for an electric one my only concern is with the wiring I was going to ground it to the frame but the postive I was thinking of running to the fuse block under the kick panel with a 20amp fuse in between where on the fuse block would I hook this up
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Hambone887
May 9, 2011.




That' not really a good idea. Electric pumps don't work well with carburetors unless they have a very high quality regulator installed also. It HAS to have a fuse inline and should have some type of shut down if the engine stalls. It also has the be mounted in the rear because electric pumps push and mechanical pumps pull. You would be much better off to find the real problem with your car and repair it.

Wrenchtech
May 9, 2011.
Hi guys. I was going to mention the automatic shutdown too. That is REAL important in the event of a crash that ruptures a fuel line. Lawyers and insurance investigators love to find modifications like that.

You might consider a collapsing fuel pickup strainer in the gas tank. The symptoms are exactly as you described except when it happened to me on two different cars, I could always make it from 5 to 15 miles before the problem started acting up. Rather than dropping the tank, remove the gas cap, disconnect the line coming into the fuel pump, and blast it with compressed air. That will shove the screen off the pickup tube. You can install a Chrysler inline filter if your car has a sintered metal filter in the carburetor. The Chrysler filter will typically last the life of the car.

Caradiodoc
May 9, 2011.
The thing I find most often when there is a fuel delivery problem in a car that old is either rusted lines or porous rubber hose which causes the pump to suck air instead of fuel.
I'm not so sure that you have even verified that lack of fuel is the issue as of yet.

Wrenchtech
May 9, 2011.
Dandy point. I'm more used to seeing fuel mist OUT of the Swiss cheese holes in my fuel lines since I do have an electric pump in the tank. Gotta love road salt!
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Caradiodoc
May 9, 2011.
Hey guys thanks for the info im going to do a little more diagonsing on the car and as far as a pressure regulator this electric pump doesnt have to have one since it only pushing a max of 6-8psi and im also thinking of wiring it in with a toggle switch to shut of if needed any additional info would be appreciated thanks

Tiny
Hambone887
May 10, 2011.
The toggle switch isn't going to cut it at all. That is just the kind of dangerous wiring that lawyers look for and can kill someone. It has to be tied to the RPM signal so it quits when the engine does. You may also find that 6-8PSI may still be too much and cause flooding. Those old school ways might work years ago but are not acceptable in this day and age.

Wrenchtech
May 10, 2011.
Hey wrenchtech I verified the spot on the fuse block where I was going to wire it has no power with the key off and power when the key is turned on acc im not sure if this is what you were getting at but if not then could you please specify thanks

Tiny
Hambone887
May 11, 2011.
No, not at all. Fuel pumps are wired to sense a tach signal so when the engine stalls without the key turning off, the fuel pump stops. That is how all electric fuel pumps work. You can't have the fuel pump continue to run in the case of collision. I have to stress that I think the whole electric fuel pump idea is a bad idea. You could easily replace the fuel lines and the mechanical pump if necessary and resolve any fuel pump issues which I haven't seen you confirm that you even have a fuel pump problem.

Wrenchtech
May 11, 2011.
Ok I completly understand what you are saying but how do I go about wiring it into the tach and where exactly is the tach signal thanks

Tiny
Hambone887
May 11, 2011.
That's just it, you don't have the computer to do that. It's just a bad idea.

Wrenchtech
May 11, 2011.

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