low fuel cut problem

[3.0 GT]

hey i currently have a 7m with turbo back 3 inch exhaust, intake, lex & 550s, and a 57 trim ct26. i am hitting fuel cut at 16psi though and it is really annoying and seems low for the lex and 550's. on stock fuel system i would hit fuel cut at 10psi. i checked all the intercooler piping for leaks and it was all good. i dont however know if the intake manifold is leak free but i did replace all gaskets. what are some things that cause a lower than normal fuel cut?

 

[radiod]

Lower air temperature (hey look, it's winter time...hmmmmmm)
Altitude relative to sea level

The lower air temperature is denser. The closer you are to sea level the denser the air is. Both of these have to be compensated for by putting more fuel in the system or you will run lean. Your AFM measures that density difference and does the adjustments accordingly, and as a result, you will get fuel cut sooner because your forcing more air mass in to you engine.

Other most probably reason (as everyone well knows) is boost leaks. Have you tried pressurising you system to try and find any leaks or did you just "go over it"?

 

[3.0 GT]

Lower air temperature (hey look, it's winter time...hmmmmmm)
Altitude relative to sea level

The lower air temperature is denser. The closer you are to sea level the denser the air is. Both of these have to be compensated for by putting more fuel in the system or you will run lean. Your AFM measures that density difference and does the adjustments accordingly, and as a result, you will get fuel cut sooner because your forcing more air mass in to you engine.

Other most probably reason (as everyone well knows) is boost leaks. Have you tried pressurising you system to try and find any leaks or did you just "go over it"?

i pressurized the system from the turbo inlet to 3000 pipe outlet and all was good. but when i do the whole system including the manifold it does not hold air very long. i thought it was going through the valves but idk if the 7m has much overlap?? if i replaced the intake manifold gaskets where could it be leaking from in there?

 

[hvyman]

did you adjust the screw at all? that solved my fc issues.

 

[3.0 GT]

did you adjust the screw at all? that solved my fc issues.

oh yeah, forgot to mention the screw is almost all the way out. anymore and there would be no threads to hold it in.

 

[CajunKenny]

You say stock fuel system. Are you running the stock fuel pump?

What are your afr's?

 

[3.0 GT]

You say stock fuel system. Are you running the stock fuel pump?

What are your afr's?

i meant back when i was on stock fuel i would hit fuel cut at anything above 10psi, but now i have a walbro 255lph fuel pump, 550cc injectors, and the lex afm. sorry for the confusion

 

[CajunKenny]

No problem.

AFR's?

 

[3.0 GT]

i dont have a wideband right now but will soon. i guess that will tell me my problem, hopefully

 

[CajunKenny]

Well, it's more information and that always helps.

I personally wouldn't run any more than 15 psi on pump gas without a WB and an EGT gauge. Those two bits of information are VERY crucial to engine safety.