fuel pressure prob.

[linksys42]

Hello, I have been having this prob for sometime now if anyone has any ideas what this might be I would greatly appreciate it. I have a B&M fuel pressure gage kit that mounts to the banjo bolt on the top of the fuel filter and with the vacuum hose disconnected on the fuel pressure reg. I am seeing 48psi, with it connected at base idle it is right at 39-40psi???? This is on a totally stock fuel system. What could be causing that high of pressures? Stock with the hose disconnected should be at 43 psi and connected it should be at 33-35psi at idle right??? My vacuum at idle is right at 19 inhg. It would be great if someone could help me to figure out why is so high. Thanks

 

[daren_p]

Well a larger pump will cause an over run condition but looks like you still have a stock pump so this shouldn't be an issue. Have you verified the B&M gauge is correct, most automotive gauges are pretty crappy as far as accuracy goes. Wouldn't surprise me at all if it was reading 2 or 3 psi high.

 

[linksys42]

Thanks for the help, that might be the case. I could see it being a little off, but 5psi is good amount. I really doubt the gage is off that much. what other causes could be the culprit? Fuel return line maybe? Also what would be the easiest way to check the gage? Thanks again

 

[linksys42]

anyone have any other ideas what could be causing the high stock pressure? thanks

 

[kazzam]

Here is another way to look at it:

If you have the fuel presure that is way too high; you should have all the problems that come with having that presure that high. Does your car have trouble catching idle? does it stall for no apparent reason? do you blow a cloud of smoke when you get on the gas?

If you answer yes to any of those, then your fp guage is reading within ballpark. If you have none of those issues, then dont' worry about it and drive as is.

Post back!

 

[linksys42]

Does your car have trouble catching idle? ----- yes accompined with a miss and idles low/erratically.

does it stall for no apparent reason? ----- no i have never had it stall on me.

do you blow a cloud of smoke when you get on the gas? ----- no but it has a wierd order. not so much like unburt fuel tho, at idle and when i get on the gas.

thanks for the help.

 

[steve]

anyone have any other ideas what could be causing the high stock pressure? thanks

Sure how you do know for sure that it's really high?
It sounds like you have checked it one way with one gauge. Perhaps the gauge is off?

Steve

 

[linksys42]

ok, so buy another gage to make sure this one is on?

 

[steve]

Unless your seeing some other indication of a problem like fuel trims out of whack or rich readings on the wideband I wouldn't worry too much about it. You can get a new gauge or make mental note that this one reads high. If it's brand new you can try getting B&M to send you another.

Steve

 

[daren_p]

The trouble with the idle could also be a number of things not related to fuel pressure (do you have a logger?). You could follow your return line back to the tank to make sure there are no physical kinks but my guess is still going to be inaccurate gauge, 5 psi while it may seem like alot to be off, defently wouldn't surprise me. Like I said the gauges they sell in the automotive aftermarket are usually very crappy gauges with a huge markup. What are the divisions on the gauge you got? See if there's anyone local that has a proper test gauge to compare yours too. I'd check it for you, but its abit of a drive to Ontario

 

[linksys42]

Yes, I have a logger. What kind of reading on the fuel trims would be normal? I know every car is different but what should I be looking for? An example would be great!!! My car has been steadily running worse and worse (loss of power, rough idle/miss at idle) like something is holding it back on acceleration. And I can’t seem to figure out the problem. The increments that the gage has go up by 2 psi for each mark 0-100 psi, its the B&M fuel pressure gage kit that mounts to the banjo bolt on the top of the fuel filter (pic below). What kind of proper test gage are you referring to? I have a fuel pressure test gage for other cars but it doesn’t have correct fitting for our cars (you think they would have put a test port on the fuel rail to test the pressure). I really appreciate all the help!!! Thanks

 

[linksys42]

Ok so I installed a new pressure gage to make sure that it wasn't the gage(it wasn't), then I thought the fuel return line, so I went and got some fuel hose and just attached it to the FPR then to a gas can that wasn't the problem. So then I said it's got to be the FPR, swapped it out with another one and still no change???? So I guess there is a pressure drop from the top of the fuel filter (where my gage is mounted im using the B&M kit) to the fuel rail??? That's all I can think of??? Any body else have any ideas??? Also I installed a walbro 190L pump and the base pressure went up 2-3psi, before with vacuum applied it was at 39 now it is at 42. Before with VAC disconnected it was at 48 now it's at 50. Id like to hear from someone that has a 190L installed, could you let me know if that's all yours just went up to when you installed it 2-3psi. Thanks again

 

[somdturbo]

I am having a similar issue. It seems the stock fuel system is running too rich. I am to believe the fuel pressure is too high.

 

[selmerguy]

Just sell that extra gauge and buy a adjustable FPR and make your FP whatever you want it to be.
Are you sure that both those stock FPR's werent crushed? That is a pretty common free mod to get alittle more fuel for more boost.

 

[linksys42]

Just sell that extra gauge and buy a adjustable FPR and make your FP whatever you want it to be.
Are you sure that both those stock FPR's werent crushed? That is a pretty common free mod to get alittle more fuel for more boost.

No they were not crushed. I have never heard of some one crushing a FPR? why would you crush a FPR when you can pick up a B&M CommandFlo Fuel Pressure Regulator for cheap? If all you want to do is up the fuel pressure. Crushing the FPR sounds like rushin roulette to me! Does any one have any ideas on this high pressure problem? thanks

 

[linksys42]

So no one else has ever run across this before? Anyone have any ideas or theories on this situation? And has anyone that installed a 190L pump recorded the PSI difference between stock and after installation? Thanks