Fuel pump pressure relief and checkvalve Options

[saigon71]

Will have time tomorrow to work on the car. 74 2.0 D-jet. Car starts right up cold but requires two taps on the accelerator to keep it from stalling - after that, it runs great. I will be checking the routing of the fuel hoses as recommended by Rich.

Another reply questioned the proper functioning of the fuel pump pressure relief and check valve in the fuel pump.

Fuel pressure set at 30PSI when the starter cranks. Pressure drops immediately to 20 PSI when the starter disengages. From 20 PSI, it bleeds down to zero within four minutes...but I have no idea if this is normal. Has anyone taken the pressure relief and checkvalve out of their fuel pump and cleaned/replaced the springs? Is this recommended?

Thanks.

[davesprinkle]

Will have time tomorrow to work on the car. 74 2.0 D-jet. Car starts right up cold but requires two taps on the accelerator to keep it from stalling - after that, it runs great. I will be checking the routing of the fuel hoses as recommended by Rich.

Another reply questioned the proper functioning of the fuel pump pressure relief and check valve in the fuel pump.

Fuel pressure set at 30PSI when the starter cranks. Pressure drops immediately to 20 PSI when the starter disengages. From 20 PSI, it bleeds down to zero within four minutes...but I have no idea if this is normal. Has anyone taken the pressure relief and checkvalve out of their fuel pump and cleaned/replaced the springs? Is this recommended?

Thanks.

The over-pressure relief valve in the pump isn't designed to be serviced. If you open up the crimped can, you likely won't be able to crimp it back together and then you'll have a serious leak. Don't do it.

Couple observations:
1. A perfectly tight fuel system, that holds pressure indefinitely, is ideal. And also unrealistic. Bleeding down over 4 minutes is fine. Don't worry about it.
2. You should have 30psi when the engine is running. 20psi isn't enough. Try turning in the adjuster screw on the pressure reg.

[saigon71]

Will have time tomorrow to work on the car. 74 2.0 D-jet. Car starts right up cold but requires two taps on the accelerator to keep it from stalling - after that, it runs great. I will be checking the routing of the fuel hoses as recommended by Rich.

Another reply questioned the proper functioning of the fuel pump pressure relief and check valve in the fuel pump.

Fuel pressure set at 30PSI when the starter cranks. Pressure drops immediately to 20 PSI when the starter disengages. From 20 PSI, it bleeds down to zero within four minutes...but I have no idea if this is normal. Has anyone taken the pressure relief and checkvalve out of their fuel pump and cleaned/replaced the springs? Is this recommended?

Thanks.

The over-pressure relief valve in the pump isn't designed to be serviced. If you open up the crimped can, you likely won't be able to crimp it back together and then you'll have a serious leak. Don't do it.

Couple observations:
1. A perfectly tight fuel system, that holds pressure indefinitely, is ideal. And also unrealistic. Bleeding down over 4 minutes is fine. Don't worry about it.
2. You should have 30psi when the engine is running. 20psi isn't enough. Try turning in the adjuster screw on the pressure reg.

Thanks Dave, appreciate the info. I would rather not take stuff apart that is not meant to be serviced! I may have mis-cummunicated a bit. I set the fuel pressure at 30PSI with a helper cranking the starter and the coil wire off. As soon as they stopped cranking the starter, pressure dropped to 20PSI and bled off from there. From re-reading the Paul Anders section on "How should it run anyway" it looks like I am in pretty good shape. I will check the hose routing to make sure everything is good, then call the D-Jet system done.

Thanks again,

Bob

[type47]

I see your comments about cranking fuel pressure, etc. What is fuel pressure when the engine is running? Should be about 30 psi as mentioned above.

[underthetire]

If it is bleeding off to fast, probably a fuel injector leaking IMO.

[Cap'n Krusty]

It's doping what it's supposed to do. Jumper the fuel pump relay and check your fuel pressure. If it's 29-31 PSI, it's good. Leave it alone. You DO NOT have a leaking injector. The Cap'n

[underthetire]

It's doping what it's supposed to do. Jumper the fuel pump relay and check your fuel pressure. If it's 29-31 PSI, it's good. Leave it alone. You DO NOT have a leaking injector. The Cap'n

I said IF!!!! (IMG:style_emoticons/default/poke.gif)

[swl]

So back to the original question - he needs extra fuel to keep if from stalling when cold. Doesn't that suggest maybe the cht is going out of spec? Although they usually go rich as they go bad right? Resistance increases?

Maybe just the idle adjust?

Sorry I can't give the answers - just questions.