Fuel Pressure getting weaker

[2.8 Bird]

Hey, I have a Walbro 255 on my 4th gen and I notice that the pressure is now down to 32.

It was 36-38 for awhile, but when I first installed it it was 40-42.

Before when my gas tank gets really low it would be at 32-34, but after gassing it up it would be back at 36. Now it's at 32 regardless.

Now here's the thing. The performance seems to be the same.

Anybody know what's going on? Is my gauge messed up? Where's the pressure suppose to be anyway.

FYI... I have stock injectors, FMU, and a SC. The pump has less than 10k on it.

[2.8 Bird]

Re: Fuel Pressure getting weaker

Hmmm, after much thought I think I will try and change fuel filter and maybe even Fuel Pressure Regulator. These 2 things, if bad, can affect fuel pressure. If these aren't it then I may take on the pump again.

[nascar24jd]

Sounds logical.

May I also suggest not allowing the tank to run so low on fuel. It's not good for the pump.

[Docta]

Re: Fuel Pressure getting weaker

Isn't 40 low pressure on these cars anyway?

[ssms5411]

Re: Fuel Pressure getting weaker

42-44 psi +5 psi at wot.

[Docta]

Re: Fuel Pressure getting weaker

Thought it was 52-55?

[GaryDoug]

Re: Fuel Pressure getting weaker

Thought it was 52-55?

Depends on how you measure it. With the engine off, it should be 48-55 psi. But the regulator will drop that down according to the level of vacuum applied. If you want to test the pump pressure while the engine is running, remove the vacuum hose from the regulator temporarily.

[2.8 Bird]

Re: Fuel Pressure getting weaker

Sounds logical.

May I also suggest not allowing the tank to run so low on fuel. It's not good for the pump.

Yes, you're right.

SSM where is your pressure at at idle?

[ssms5411]

Re: Fuel Pressure getting weaker

Yes, you're right.

SSM where is your pressure at at idle?

Mines at 44psi. This is with a Walbro 255.