Fuel pressure ?

[mimiGLH22]

OK at idle when you hit the throttle is the fuel pressure suppose to go up or down? Every time I press the gas at idle the FP goes down. I have it set at 32 psi but when i hit it, it shoots down to about 20 psi. I am on the verge of mounting it in front of the windshield so I can see where it's at when I am actually moving.

-Chris

[crazymadbastard]

Sounds like the fuel pump is not keeping up with the engine's needs.

[mimiGLH22]

Quote:

Originally Posted by crazymadbastard Sounds like the fuel pump is not keeping up with the engine's needs.

Damn that sucks. It's a brand new 255 Walbro. If that's the problem then I guess that makes sense to why she running so freakin rich.

[86Tona]

Quote:

Originally Posted by mimiGLH22 <snipped>If that's the problem then I guess that makes sense to why she running so freakin rich.

If the fuel pump isn't able to keep up with demand, and if it drops pressure under WOT or even when you get on it a little then how could it be causing a rich condition? I would think the opposite would be true. With less pressure and with the pump not being able to keep up with the demand for fuel, I would think it would starve the engine and lean it out.

[crazymadbastard]

Quote:

Originally Posted by mimiGLH22 Damn that sucks. It's a brand new 255 Walbro. If that's the problem then I guess that makes sense to why she running so freakin rich.

I would double check the install, see that there are no kinks or loose hoses or claps etc.

[xrattiracer]

you are suer you are looking at the gauge while the throttle is open? pressure will go up briefly while the engine is accelerating, but when you let off and the engine is deccelerating the pressure will be lower than normal.
it all happens very quickly when youre just stabbing the pedal.

[Marcus86GLHS]

i just went thru over lean fuel probs it was a very clogged fuel filter, so replace that 1st it takes 10 minutes and its very inexpensive. i plan on replacing my fuel filter at the beginnig of each season every year after experiencing how a bad fuel filter can drastically hurt your engine operation.

attaching the fuel press gauge to the windshield and taking it for a test drive is an excellent idea, i also did that to be sure that as manifold pressure went up 1 psi, fuel pressure also went up 1 psi.

good luck.

[tryingbe]

What fuel line did you use inside the tank?

[mimiGLH22]

Quote:

Originally Posted by 86Tona If the fuel pump isn't able to keep up with demand, and if it drops pressure under WOT or even when you get on it a little then how could it be causing a rich condition? I would think the opposite would be true. With less pressure and with the pump not being able to keep up with the demand for fuel, I would think it would starve the engine and lean it out.

That's what i thought. I feel like this car is playing games with me.

[mimiGLH22]

Quote:

Originally Posted by crazymadbastard I would double check the install, see that there are no kinks or loose hoses or claps etc.

See now it ran perfect when installed for about a month until I blew my motor. Now that the motor has been completely rebuilt, I am running into all these problems. The fuel filter was replaced about a year ago. I watched them install the pump and it looked to be pretty clean of kinks and so forth. It worked fine. Later on today I'll post after I take the car out while watching fuel press.

[mimiGLH22]

Quote:

Originally Posted by tryingbe What fuel line did you use inside the tank?

Don't remember but it ran awesome well after the install. Assuming that, I would think the fuel lines were correct.

[Marcus86GLHS]

"...........The fuel filter was replaced about a year ago............."

do it again.

[tryingbe]

Quote:

Originally Posted by mimiGLH22 Don't remember but it ran awesome well after the install. Assuming that, I would think the fuel lines were correct.

When is the install?

What fuel pressure do you have if you prime the pump with the car NOT running?

[mimiGLH22]

Quote:

Originally Posted by tryingbe When is the install? What fuel pressure do you have if you prime the pump with the car NOT running?

I installed it about 7 monthes ago. It ran great for me.
Right now the fuel pressure is at 0 when the car is not running. Now I remember it not being like that. Before when I turned the car off the fuel pressure would stay put. Somethings wrong. It might actually be the AFPR. It did give me some problems adjusting a few monthes ago. What do you think?

[mimiGLH22]

Quote:

Originally Posted by Marcus86GLHS "...........The fuel filter was replaced about a year ago............." do it again.

Sounds pretty seroius. I'll tend to it next week. Thanks.