So, I am in the midst of a nitrous install, so i recently installed a fuel pressure guage. in most of the shop manuals, it says that with key in and in the on position, but engine off, i should see 43psi of fuel pressure. I see about 0-10 psi. the car is also stuff to start, takes a few cranks and sometimes a little press on the gas. it seems the fuel pump is not pumping enough fuel initially, or could the fuel filter be due for a change? maybe both, maybe neither? I am scheduled for a fuel injector cleaning at the dealership in the next two weeks, but the fuel pressure (or lack of) before the car starts is what has me thinking. I want to make sure I have the fuel system in tip top shape before running the happy gas, so any help greatly appreciated. Other than this issue the car runs great once it is started. any ideas

 

I never got 43psi of pressure with the engine off. I get about 15-20, and everything is fine. This goes for both the stock pump and the Walbro.

Trouble starting may be the filter, or you are losing that little bit of pressure that the system should have when starting. Maybe a small leak somewhere?

If your FP is steady when at WOT then you should be fine.

I just went ahead and upgraded the pump and installed a FPR before doing my NOS install, because I knew I would do them down the road, so why not just do it all at once? If you want to venture over 50-shot it makes sense to do it now.

 

Start with the fuel filter. It is only 10 bucks or less and will only help the fuel system. Then if it is still giving you issues maybe try the fuel pump. Since your getting into nitrous try going the way oof walbro and get one of the upgraded ones.

Also double check top make sure the gauge is correctly installed.

SuDZ

 

Thanks for the help gang.

I had the walboro 255, for my initial plan to run dry nitrous, but since going direct port nitrous the walboro 190 is on the way. So maybe when the new pump is in it will fix the problem.

The guage seems to work when the car is running. At idle, I set the FPR to about 35 psi, and at WOT the main fuel pressure shoots up to about 44 psi, then settles back down.

Since I am going to change the fuel pump anyways, i figure I will now also change the fuel filter.

I forgot to mention that my Nitrous setup is a little wierd. i am going to be running the NX direct-port kit. now, with our fuel pressure, this kit goes from 150-300 shot. I didn't want to start that high, so i had to run a second regulator, on the Tee'd in fuel line that feeds the fuel solenoid. The second regulator bumps the fuel flowing to the fuel solenoid down to 10psi (when flowing).

When the car is up and running, and I sprayed to test the fuel flow (Sprayed from fuel solenoid through test jet, into a rag), both lines were at the corect pressure, and the car seemed to handle the spraying of extra fuel without missing a beat.

Do you think that the pump can't handle feeding both fuel lines until the car is up and running.