View Full Version : fuel pressure issues

08-13-2015, 01:32 AM
I am trying to figure out an issue with fuel pressure. When I turn on my key the pump turns on but my pillar gauge does not show boost so I jumper the test port lead and I have 42psi of fuel pressure on the pillar gauge. I though the gauge was an usse so i used a remote fuel pressure gauge on the shrader valve and I only have 32 psi when the key turns on and it slowly bleeds down. I have checked the lines for leaks and even checked the return hose with air pressure and there are no leaks that I can find in the system.

The strangest part is the car does start and run. before the 2012 shootout I had fuel issues and hurt the engine so I wonder if the fuel system issues are from back then. I am thinking of gutting the fuel system entirely and start again as this is not working.

my fuel system coinsists of the folloing.

aeromotive stealth 340 pump
braded lines to a solid line that connect to the fuel filter. then the solid line return to braided line under the fender and it Ts off to both fuel rails feeding 80lb injectors and the fuel lines return to the fuel pressure regulator on passenger fenter and a retun line runs to the tank.

I have pulled the line off the fuel pressure regulator and it shoots fuel out when the key goes on.

what would cause the pressure to bleed down? could I have a bad injector that is leaking? everytime I start the car there is black smoke too but once running it seems to clear up. It won't idle but I think that is a seperate issue. How do I test if the injector plugs are plug into the correct injectors? the wire colors look the same and there are no marking that I could find on the leds. I can compare them to a spare harness but it there is a way to test with a meter that might be earlier.

Though the car runs it does not seem to accelertae well I feel the fuel issue is related and if I am looking fule pressure at idle it makes sense it will occur when driving too.

any help would be appreciated.


sam jones
08-13-2015, 04:02 AM
Good morning

Start by troubleshooting the fuel pressure regulator.

(1) With the engine cold pull the vacuum line off and check for cracks and evidence of fuel leakage either visual or smell. Correct defective parts.

(2) Start engine. Pull vacuum line off. Check for fuel pressure regulator for leakage. May take a couple of heat cycles before the regulator starts to leak/weep/wick fuel.

(3) Install fuel pressure gauge. Disconnect the fuel-return line. Plug it. Build up fuel pressure by cycling key on and off. In 30 seconds, fuel-pressure drop should be less than 5 psi. If the drop is still more fuel is probably leaking past the fuel-pump check valve because with the return line plugged, the regulator could not be causing the drop in pressure. If the drop is now in spec, a faulty pressure regulator caused the drop because blocking off the regulator cured the pressure drop.

If the fuel pressure regulator passes check the fuel rail/injectors for leaks. Carefully remove the fuel rail with injector in place. Build up fuel pressure cycling key on and off and watch the injector(s) for drips. If you see more than 1 drop in two minutes, clean and re-test. If this test fails replace injector(s).

Good luck.

08-13-2015, 09:35 AM
Thanks I will try that. I just noticed I had fuel flow backwards. The line from the filter goes to the regulator then runs to the two fuel lines and then two Braided lines run to a t which is the return hose to the tank.