[MustangMabry]

What is the normal fuel pressure for a 2v motor with 24 lbs. injectors and a aeromotive fuel system?

 

[RyanGT]

Fuel pressure should be around 40 driving around.

 

[Trick Tuners]

Fuel Pressure and the FRPS - Trick Tuners Forums

 

[cliffyk]

+1, if you read it at the fuel rail, or the generic PID through the OBD2 port, with a scanner, it will be 40 psi + the intake manifold pressure (vacuum = negative pressure).

 

[Trick Tuners]

+1, if you read it at the fuel rail, or the generic PID through the OBD2 port, with a scanner, it will be 40 psi + the intake manifold pressure (vacuum = negative pressure).

Nope. What you said is only for the rail pressure. The data off the frps should read 40 all the time because its pressure referenced.

 

[cliffyk]

You are correct, that's what you get for relying on 62 year-old memory...

The raw return value for generic PID 010Ah is rail pressure in psig (gauge pressure), which has to have 14,7 psi added to it to get the pressure drop across the injectors.

I was recalling that the raw value was less than the drop, forgot about why...

 

[Eagle2000GT]

Yep. And the result is that my aftermarket fuel pressure gage swings from 30-50 psi as I open and close the throttle. But if you datalog the fuel pressure it says its a constant 40 psi. You can actually test the aftermarket gage by turning on the ignition but not starting the car. My gage will swing up to 43 and then settle at 40 psi (zero vacuum and zero boost).

P.S. The aftermarket gage will also show an increase in fuel pressure when the weather is hot. This is to prevent vapor locking the fuel rails. My aftermarket gage has read as high as 50 psi at idle.

 

[blackedoutaddition]

sorry to hijack

but at idle i am reading 20 psi

can someone help me i just installed the gauge and that is what i an seeing

 

[Trick Tuners]

sorry to hijack

but at idle i am reading 20 psi

can someone help me i just installed the gauge and that is what i an seeing

I'd bet that the gauge is wrong. Idle with stock cams (~-10psi ~= 22"Hg) should be 30psi.
Fuel Pressure and the FRPS - Trick Tuners Forums

 

[blackedoutaddition]

I'd bet that the gauge is wrong. Idle with stock cams (~-10psi ~= 22"Hg) should be 30psi.
Fuel Pressure and the FRPS - Trick Tuners Forums

does it matter if i have cms 2.5 blower cams

 

[Trick Tuners]

I would guess around -8 psi of vac, so 40-8=32.