I just finished installing an electriuc fuel pump on my car and was wondering: With a dead-head style (non-bypass) fuel regulator I see the pressure climbing before I actually crank the engine. Is the pressure read from the guage the pressure at the regulator or the pressure going to the carb? Reason I ask is, that I saw the pressure climbing upwards of 10psi before I cranked the engine and then it read a steady 6psi.

The best most accurate way to set your fuel pressure with an electric pump (especially a dead head system) , is to disconnect your fuel line and stick it in a 5 gallon bucket (free flowing) and set to the desired pressure. Beware that tempature and altitude changes the density of the gasoline and will cause pressure changes. I prefer to run a return style system. If you are using the Holley regulator (I don't care for them at all), you will be adjusting the fuel pressure all the time.

Yes, it is normal to see the pressure climb before the car is started. One suggestion, start the car before you turn on the pump. You should have enough fuel in the bowls to start the car.

Royce

After getting the pump and regulator adjusted to 6 psi for my Edelbrock carb, last night I started her up and when I checked the guage (liqui-filled) screwed into the regulator I saw that it was pegged at 15 psi! :eek:

I immediately tried to adjust the regulator down, but the screw had no effect. Couple of questions:

1. Does the guage screwed into the regulator show the pressure beign applied from the pump to teh regulator or does it show the pressure from regulator to carb?

2. What damage could have occurred to the carb (Edelbrock Performer Series 750cfm) if the guage was correctly reading 15psi at the carb? Do I need to replace anythign in the carb?

3. Can anyone recommend a good regualtor in the case that this one is hosed/bad? Is it unusual for a regulator t have a problem like this?

Thanks!
- Steve
2.

Adjust pressure with Royce's instructions.

Answers:
1.If gauge is mounted on the SECondary side of regulator, (OUT), then it is between the reg and carb.
2. Nothing would be wrong with the carb if overpressurized. Should have seen fuel coming out of bowl vent(s) flooding the intake manifold. Might check oil level of engine to make sure all has not leaked into crankcase. Maybe later in the day, cahnge oil and filter to remove fuel-diluted oil.
3. It is not unusual for reg to do this event. Holley does sell a separate diapharm and spring for their regulator.

If there is no pressure on the system, gauge should read 0 psi. If not, then gauge is bad or jammed into its current reading, rap it with a rubber hammer. graemlins/thumbsup.gif

Everett,

Thanks a bunch.

It's hard to tell where the guage is mounted (which side). I run a summit regulator and the guage screws into the center of the unit, not towrds either side.

You said it wasn't unusual for this kind of spike to happen. Any ideas what causes it? Also do you think the regualtor is hosed if I turned the adjustment screw and nothing happened? I actually turned it so far out (to lower pressure) that it came out! and still no decrease.

BTW I believe the guage itself is fine b/c when I shut off the pump guage read zero.

As Royce suggested, its deadheading itself. There is no return path back to the tank for the released fuel to return. Therefore, regulator becomes useless and pump deadheads.

There must be an exscape path.

I have the same regulator with the Summit elect pump. This pump and regulator combo is designed to work both as a dead-head setup or a bypass type setup.

I believe most carb elect fuel pumps (I know Holley and Aeromotive) are designed to work in a deadhead config. I beleive there is a bypass valve in the pump when the pump reaches it's pressure limit.

I have a 3/8" NPT to -6AN adapter with a 1/8 NPT port for the gauge. I have it installed on the carb side of the regulator and the port on the reg is plugged. If you want, I can move my gauge to see if the pressure reading changes, but I doubt it will.

I'm having a problem where I set the pressure, then sometimes, it creeps up causing my carb to flood. I shut it off and then it is back to normal again. It's only happened twice, but I need to keep an eye on it.

Ambelfinie,

That would be great if you could try your guage in the regulator port and see if there is a difference.

What I have done for now is since the regulator how 2 output ports I used one to the carb and installed a bypass line back to the tank in the other one.

This solved my problem of getting a steady 5psi on the guage. Now I'm a bit concerned that maybe this regulator wasn't designed for a bypass, but rather the 2 output ports are for dual line carbs. I say this because I had to adjust the nut almost all the way in to achieve 5psi - and you can feel that that bypass line is definitely working if you touch the hose.

Let me know what you find.

Thanks!
Steve

Steve, I'll move my gauge this weekend and let you know the results.

I've thought about using the second port (yes, it is intended for use with dual feed carbs) as a return line, but I could not think of a benefit it would provide.

Did you put a restriction in your return? If not, you may run into a problem of the carb not getting enough pressure, especially at WOT. I would fill the return fitting with epoxy and then drill about a 1/16" hole in the epoxy. This will keep fuel flowing through the regulator at all times and should not pose a problem with WOT pressure. I still don't understand what improvement this will give as these regulators are designed to be run without a return, but I'm open to discussion on the subject.

I moved the gauge and the pressure was the same. I decided just to leave it on the FPR.