Fuel Pressure

[2003RedfireVert]

Can somebody confirm for me how I set my BASE fuel pressure with a return style? Do I set it to the desired pressure with the vaccuum hose UNHOOKED from the regulator while the engine running?

 

[MG0h3]

Vacuum line unhooked yes.

Engine running or off should be the same as long as pumps are running. If you see a difference between running or not, there’s an issue.


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[2003RedfireVert]

Thank you!

 

[cj428mach]

Easiest way is to start car with vacuum line hooked up and log it, then adjust fuel pressure until drop across injectors reads what you want it to.

 

[2003RedfireVert]

Easiest way is to start car with vacuum line hooked up and log it, then adjust fuel pressure until drop across injectors reads what you want it to.

Another good way. It’s like 49-50psi across the injectors right now at idle. Way too high

 

[Soap]

The best way to do it is to start a datalog with KOEO and adjust accordingly. This of course assumes you have kept the FRPS in place.

--Joe

 

[2003RedfireVert]

I’ve done my adjusting via datalog and my pressure now reads 40psi drop across the injectors. My mechanical guage is reading about 5psi under what I see in the datalog. It runs fine. I probably shouldn’t be worried but is this normal?

 

[01yellercobra]

Well, the pressure drop across the injectors should be just that. It's saying the pressure at the outlet of the injector is 40psi lower than what's at the top. IIRC it shouldn't change unless you have pressure drop due to not having enough fuel pump. The mechanical gauge is reading the actual pressure in the rail.

As long as the A/F is where it needs to be and injector duty cycle is good I wouldn't worry.

 

[2003RedfireVert]

Sounds good. I won’t worry. AFR and duty cycle are good.