fritts

iTrader: (5)

Well I finally sorted out my vacuum problems so the idle is great except for one thing it is running rich as can be. I hooked up the fuel pressure gauge and low and behold its sitting at 38-40 psi at idle. Throttle response also lags like its running rich. Yes, the regulator is hooked up. I guess the only other thing that could cause the issue is a leaking injector. But with the new o-rings and flowed, cleaned injectors I am looking else where. Is this pressure at idle unacceptable. I believe it is but I want to here about others experiences with fuel pressure. As another note I am running a PFC, walbro pump and no fuel solenoids? Could this be a problem? Also if it is the FPR should I go aftermarket and what type should I get?

Thanks

cewrx7r1

iTrader: (2)

That is the normal FP for 0 psi boost. Maybe the FPR hose/s or DPF soleniod are bad. You need to test your fuel pressure under boost.

Boost FP = ((0 psi boost fuel pressure) + boost pressure)

fritts

iTrader: (5)

All new hoses for the FPR. I do not have the DPF solenoid hooked up. But why would this have any bearing on the fuel pressure I thought the FPR controlled it? If the DPF solenoid is needed for stock fueling can I just tune that area of the map for the pressure. I guess I though the FPR still should be giving me around 32 psi at idle.

charliegt

What is fuel pressure when F/P and GND jumped, and ignition on (car not running)? It should be 36-38psi. If it isn't, your fuel pressure regulator is bad. (I'm ordering mine on Monday).

-Charlie

fritts

iTrader: (5)

Pressure jumped is correct. Its just that it does not change at idle. Which from what I understand it should.

Joe Geiman

You might check and see if your pump is putting out sufficient volume. You could do this by doing a fuel pump volume test with a jar and a stopwatch. I'm not sure what the volume spec is for the pump you are using.

You could use a "Labscope" to check the fuel pump by connecting the scope to the pump hot lead and looking at the fuel pump waveform. a comm bar short will spike the waveform but the normal result will be a Double wide "lobe" in the wave form caused by an "open" comm bar.

If these abnormalities show up in the pump "waveform" then the pump is not producing sufficient torque and therefore insufficient volume.

Keep in mind it is possible to have sufficient pressure with a defective pump.

Joe Geiman
aka: 2turbos

Linder Technical Services
The Injector Gurus
4-D Gasoline Alley
Speedway, In 46222

fritts

iTrader: (5)

Well I checked the FPR while in idle condition and boost condition via a vacuum and pressure pump. The FPR worked just fine. Pump had no problem holding 75 psi of pressure under boost pressure. Its just that the base fuel pressure is sitting at 42 psi. Could the earls fuel filter and walbro pump cause the raised pressure? Should I just tune the increased pressure out as the FPR works? Or is this signs of a damaged FPR and I should replace it?

Thanks

fritts

iTrader: (5)

Also what afr's should I see at idle?