I have been noticing low fuel pressure for the past few weeks. I changed my fuel filter about 2 weeks ago and nothing has changed. With the car running and the vacuum removed from the regulator, I only get 37-38 psi. I get the same psi at WOT with the vacuum hooked back up. I know 41-43 is normal. What do you think it is?

 

anyone?

 

Fuel pump possibly? Bad regulator?

 

try to hook up a clean vac hose to the line going into the regulator and sniff to see if you smell gas. If you do its toast cuz the diaphragm is gone. You also might wanna pull it off to see if its clogged like mine was. Have you done the filter lately?

 

While it may not be "optimal", the pressure should be enough to get you by for a while. You might have a decrease in performance at WOT if the pressure is not enough. Some O2 readings at WOT might give a clue. I guess the regulator is a possibility (though, I have my doubts) and is sure easier to change than a pump.

 

Yeah, I did the filter a couple weeks ago.
If the regulator was bad, wouldnt the pressure be reading too high because the diaphragm would not be able to pull the pressure down during normal driving?

 

When you turn the key to the On position but not start, does the fuel pressure go to 43psi and then when you start it does it drop?

If not its a bad regulator.

A bad fuel pump would cause the fuel psi to continue to decrease.

 

With just the key on, the pressure is at about 37-37, then when its starts, it drops to about 33

 

just for a refence mine starts at 42 at prime and goes to about 38 running and after it gets hot it goes to about 33

 

Another thing.
When I get gas, when I take the gas cap off, I never hear the pressure releasing hissing.

 

Interesting.

Mine goes to ~36.5 at prime, stays around there while running at idle, and goes to ~43.5 at WOT.

You might have a vacuum leak somewhere on the intake manifold. Check all the lines.

 

Look for a little puff of black smoke when the car first starts after sitting. This indicates a rich condition caused by fuel poolingi n the intake manifold. It happens when a pinhole forms in the regualtor diaphram allowing fuel to pass through the vacuum line into the intake manifold.

Also, follow the procedure in the GM manuals. It is very good at isolating the cause. It basically allos you to isolate the 3 parts of the system to determine where the pressure leak is. I have had the the regulator go and the check valve in the fuel pump at two different times. Pray it is the regulator.

 

So your regulator is healthy.

I can't think of any obstruction that you would have in the fuel rails.

Probably the fuel pump.

Save yourself some time and get a Walbro from Racetronix.

 

thats ok in the last month Ive had to replace the factory pump, 2 stock replacement pumps and finally dropped in a Walbro from Holley. Also did a set of 8 19 pound injectors cuz mine were clogged and a set of 24 pounders from Brian and then a regulator. So the good luck genie is one my side

 

Problem fixed. Iput a mechanical gauge at the schrader valve and come to find out my crap sending unit for my digital gauge is crap. Whew, that saved some dough.

Thanx for your help.