Fuel cut on lex afm+550's

[kotu100]

like it says, im getting Fuel cut at about 15psi on my 64mm turbo. i have the lex afm, 550cc injectors and afpr set @ 40psi. i've seen others running higher boost on similar turbos with the same setup. any idea what could be causing this? i dont have any boost leaks either.

 

[montego6500]

fuel controller?

 

[kotu100]

SAFCII, i knew i forgot something...

 

[MRSUPRA]

I would hit fuel cut around 19-20psi before I installed my FCD. Did you back out the AFM screw all the way?

 

[jdub]

Can you be more specific than "64mm turbo"? Stock IC and piping?

 

[kotu100]

I would hit fuel cut around 19-20psi before I installed my FCD. Did you back out the AFM screw all the way?

i did not, i thought that was only needed to rough tune if no other fuel controller was present.

Can you be more specific than "64mm turbo"? Stock IC and piping?

its a master power t-64 P-trim with .68a/r hotside

upgraded to 24x11x3 bar and plate fmic with 2.5" alum piping.

 

[jdub]

That turbo will flow a lot more than any CT26 upgrade...and, more important, at a lower psi. You've also removed any IC and piping restrictions. Considering fuel cut is determined by air flow past the AFM sensor (not psi), you could easily be at max flow psi on that set-up for the Lex.

FYI - I hit FC at 17-18 psi on an SP61 with a smaller IC and identical piping.

You could try screwing the AFM screw out to increase bypass air....you will have to compensate with the SAFC.

 

[kotu100]

i'll give that a try tomorrow.

any chance it could be the stock fuel pump?

the a/f's dont get too lean (highest i've seen was 12.5 but richened it out)
and i know fuel cut is activated by the AFM, not lack of fuel. so i don't think it could be, but figured i'd throw that up there.

could anyone recommend, should i go with a map ecu II, maft pro, etc? i deff don't have the cash for full standalone.

 

[jdub]

It's not the FP

The MAFT Pro can convert to speed density...no more AFM.

 

[kotu100]

does the pro eliminate the afm or MAF completley? would i be able to run an open turbo (with a filter of course)

i did some quick searching but couldnt find anything good. if u could point me in the way of a link, or some info, i'd be much apreciated.

 

[jdub]

Eliminates the AFM...you'll need an intake pipe for the filter. You can vent the BOV to the atmosphere (no issues) and put a small filter on the ISCV. All speed density requires is a pressure and temp sensor to make the flow calculations for the ECU. I would start by looking in the Piggyback EM section.

 

[kotu100]

backed the screw out as much as possible, still hittin fuel cut...

i think it may just be cheaper for me to get a FCD.
i know its there for a reason, but if i keep it @ a safe a/f i shouldnt have any problems... right?