Fuel Pump Wiring problems

[Spdrcer34]

This is for my 1980 Cutlass Calais, but I'm using all GN parts, and 1980 was THE LAST year the Cutlass had no ECM, so I don't have one.

In an effort to install, AND wire up my new In-tank Fuel pump ( GN tank, Walbro340, Racetronix Harness) I have run into a problem.

There is supposed to be a fuel pump switch connected to a Oil Pressure switch; no pressure = no power.

There is also a wire that is supposed to go to the ECM to trigger the pump to 'pressurize' the lines for a few seconds then shut off for ease of start-up, and so that the pump doesn't run-on while the key is in the ON position, but the engine isn't running.

How would I/should I wire this up so that I have some type of fail-safe system WITHOUT an ECM, or Oil Pressure switch?

If I have to install a Oil Pressure Switch, where ELSE besides the Factory location can it go? I have thought of 'hiding' it with a S/S braided line that runs across the intake, and having BOTH the Oil Pressure Sensor (for my Gauge) and the Switch (for the pump) somewhere in the engine compartment. Anything is possible I suppose.


Ryan

 

[John Larkin]

What do you mean "fail-safe"? Like if you have a wreck and want the fuel to be cut off? If that's the case, get an intertia switch from a Taurus. They are in the trunk by the quarter panel. Has a button that will pop breaking the connection upon a jarring impact.

What engine are you using BTW?

 

[salvageV6]

Sounds like you need a 3 second timed relay and then a relay that latches with rpm or oil pressure.

Anything electrical on that car that energizes or works ONLY when the car is running for sure. ie. not in start mode or key on but the car actually running???

 

[Spdrcer34]

I'm have a NA, carb'd Olds350, for now. I will eventually upgrade to a custom EFI Olds 350 or 403.

I haven't found a source for the 'timed' relays. I looked for them in the past so that there is power to the windows and such for ~15 seconds for running the windows/locks/trunk right after I turn the car off.

Ryan

 

[John Larkin]

My first car had an Olds 350. I recall the oil pressure switch being right in front of the intake, on top of the block.

Check this out: http://www.electronickits.com/kit/complete/elec/ck1605.htm

Right there is a kit (the third one) that has variable timing controlling a relay. Now the trick will be to bypass it once the car has started. You will probably have to run power to the pump in parallel through the oil pressure switch AND this timed relay so that when the relay times out again, the power feed through the oil pressure switch basically takes over. In my mind, that is what I envision. Reality could be different. Looks like a fun project for $25. Good luck. Don't forget you are going to need a regulator for that carburetor. It can only handle about 5 - 7 psi.

 

[Spdrcer34]

I know about the pressure differences. I will be running a Mallory Bypass Regulator, utilizing a 3/8" Feed AND return line. People have tried the 5/16" line and had problems getting the pressure down below 10 psi.

Ryan