Should I be hitting fuel cut with these mods?

[reeds420]

Within the past few months i've been modding my car and I am finally done installing all my parts. i had idle issues with the new turbo i just put on but it's all been sorted out and the car runs perfect now. I went to test drive it today and it went well except for the fact that i hit fuel cut at 14 psi. i know the fuel cut is higher than it was with the stock CT and AFM but i figured i could run more boost than this with my mods.

Should I be hitting fuel cut at 14 psi with these mods:

- SP61gt
- Lexus AFM
- Evo 8 Pink top 560cc injectors
- AFPR
- walbro 255lph fuel pump
- AEM UEGO Wideband
- SAFC 1
- 3" exhaust w/DDP
- CX racing FMIC
- TurboXs manual boost controller

The current settings are as follows:

- SP61gt is on wastegate pressure which is 14 psi so i can't turn it down any more
- Lexus AFM adjustment screw is backed all the way out
- AFPR is at 40 psi with vacuum line disconnected
- Walbro 255 does NOT have the 12V mod done yet
- AEM Wideband is at 10.5
- SAFC 1 is on hi-throttle setting of +10 from 3000 rpm to 6500 rpm
*NE points start from 3000 rpm in increments of 500 rpm up to 6500 rpm


i also have com CEL codes which are 13 (rpm signal), 14 (ignition signal), and 34 (turbocharger pressure abnormal). I'm assuming i got all of these due to hitting fuel cut. I've done some research and from what I've seen, some guys have been successful with these mods. could it be that i don't have the 12v mod done or is that even a factor? i know that 10.5 is rich so I'm gonna subtract some fuel until i get mid 11's. I am going to do another boost leak test which will be my 5th one within the past month and see what the results are. but is there something i am overlooking? Thanks!

 

[black89t]

possibly yes you should be hitting fuelcut with how you have things now. mainly because of your afc settings. by adding fuel you're going to make fuel cut come on earlier. you are pretty rich anyway so id try to tune it to where the afc setting are close to 0. use your afpr to get it where you want it mainly if anything get it a little rich by fp. then pull a small amount on the afc to get it exact. doing it this way will raise fuel cut even more than if its zeroed out. and espicailly raise it since you are adding quite a bit. id say try to keep your afc adjustments under 10 if possible. which you should be able to unless you really turn up the boost....

 

[reeds420]

man i was thinking completely opposite of what you are saying! ok, i will start with hi-throttle settings at 0 and see what that yields as well as bumping up fuel pressure. as of right now it's at 40 psi. is there a specific threshold that i do not want to surpass on the AFPR psi-wise?

 

[black89t]

my fp is at 45 plus 17-18psi of boost so thats 62-63psi of fp under boost. idk what the limit is on fp but thats what mine is at and it pulls really nice!

 

[Poodles]

Codes 13 and 14 won't be from fuel cut. Also a larger turbo will flow more air at a lower PSI.

That along with your SAFC settings is going to mean fuel cut.

Another few things:
- Pulling the screw all the way out of the AFM is adding a lot of air. Fuel pressure should be adjusted to match to get the idle trim correct (have to look at what the narrowband is seeing to see if it's adding fuel). Bit more complex and I can't currently remember the details (been a long day lol)
- I'd be looking for a different, lower wastegate spring (if it's replaceable) as you're not going to be tuning for 28psi on a setup such as yours.

I'm sure there's more I'm forgetting...

 

[reeds420]

Ok! Ill start there and see how it works out! Not trying to run that much boost on pump gas. Maybe 15-16 psi at most. What turbo u running?

 

[reeds420]

Codes 13 and 14 won't be from fuel cut. Also a larger turbo will flow more air at a lower PSI.

That along with your SAFC settings is going to mean fuel cut.

Another few things:
- Pulling the screw all the way out of the AFM is adding a lot of air. Fuel pressure should be adjusted to match to get the idle trim correct (have to look at what the narrowband is seeing to see if it's adding fuel). Bit more complex and I can't currently remember the details (been a long day lol)
- I'd be looking for a different, lower wastegate spring (if it's replaceable) as you're not going to be tuning for 28psi on a setup such as yours.

I'm sure there's more I'm forgetting...

I emailed Sound performance to see if they offer a lower spring. They haven't got back to me yet haha. I'm a zero out my settings and make some adjustments to my idle screw and see how it performs.

 

[reeds420]

*update*

i made adjustments as follows:

- fuel pressure at 35psi w/vacuum line disconnected
- safc hi-throttle settings at -5 from 3000-6500 rpm
- Lexus AFM adjustment screw @ 8 1/2 turns out from all the way down

yield = fuel cut at 17 18 psi possibly more
AFR's look solid at 11.5 until fuel cut
VF @ 1.8/2.5 fluctuating

the issue i'm having is with either the wastegate or my Divorced Downpipe. boost is creeping pretty bad and doesn't stop until i hit fuel cut. I will try to contact Sound Performance again to see if they offer a softer wastegate for the SP61. i feel i could control boost better from a softer spring and my boost controller. also my Divorced Downpipe doesn't have the tab welded on and that may be contributing to my boost creep as well so need to get that situated. my fuel cut was definitely raised a few PSI with the new settings on the AFPR and SAFC (thanks black89t), but since boost seems somewhat uncontrollable at this point, i need to back off before something goes boom. I've been lucky enough thus far but no need to push it.

 

[reeds420]

Codes 13 and 14 won't be from fuel cut. Also a larger turbo will flow more air at a lower PSI.

That along with your SAFC settings is going to mean fuel cut.

Another few things:
- Pulling the screw all the way out of the AFM is adding a lot of air. Fuel pressure should be adjusted to match to get the idle trim correct (have to look at what the narrowband is seeing to see if it's adding fuel). Bit more complex and I can't currently remember the details (been a long day lol)
- I'd be looking for a different, lower wastegate spring (if it's replaceable) as you're not going to be tuning for 28psi on a setup such as yours.

I'm sure there's more I'm forgetting...

i found my codes 13 and 14 are from my BEE-R rev limiter when it cuts ignition while in operation. took me a while, then it came to me haha