fuel cut issues.....

indy_mk3

boost-creep
Oct 15, 2007
100
0
0
33
kelowna
ok ill get straight to it : ive got a stock jdm 7m and i have the following mods : .57 trim ct26,BIC DDP + full 3'' exhuast with a straight open megan N1,K&N intake,ARC delta intercooler,compleate 2.5'' pipes, cooleeze intake pipe, and a innovate wideband to make sure it doesnt go boom and we havent tuned the car at all yet so the wastegate is opening at 5psi then slowly creeping to 14+ and its hitting fuel cut...this was an obvioius problem i thought would occur but it still hit 285 wheel hp and 334 ft on the dyno hitting fuel cut at almost 4500 rpm....now comes my questions : what is the best way to eliminate my fuel cut issues?? should i do the whole Lexus afm with the 550's & etc. off of suprasport? or should i just get big injectors,fuel pump,fuel rail,and pressure reg. and go maft pro?? some of my friends are saying just get E manage but im not to sure what to do i was thinking of just getting maft pro then getting bigger injectors with a walbro fuel pump + fuel rail and a fuel pressure reg and a boost controller to open it at 10psi then just let it creep to w.e , im aware that this isnt the safest thing on a oem HG but i wanna do whatever i can do then do a full build once it blows up lol, this is why i was thinking i might as well go maft pro now....please give me suggestions!!!
 

indy_mk3

boost-creep
Oct 15, 2007
100
0
0
33
kelowna
we have a boost controller for it but we just havent set it up yet...didnt really see the point of putting it on having fuel cut without it
 

jdub

Official SM Expert: Motor Oil, Lubricants & Fil
SM Expert
Feb 10, 2006
10,730
1
38
Valley of the Sun
First, to make one thing very clear, FC is based on airflow through the AFM. 12-14 psi is about where it will occur on the stock AFM. A Lex AFM will get you to ~18 psi of boost. The BBC DDP and 57 trim CT26 is going to put you at FC at a lower RPM as you discovered.

Why am I telling you all this...get a MAFT pro and switch to speed density. You do not need to upgrade fuel right now (the fuel rail is plenty big BTW), but to make more power you will eventually. At that point, bigger injectors, a Walbro, and an AFPR goes on together IMO. You will need to eliminate or drill out the J tube return fitting as well.

BTW - next time you post, use sentences and paragraphs...it's a lot easier to read. It is also why I did not responded to this thread earlier.
 

IwantMKIII

WVU MAEngineering
Jun 12, 2007
2,477
0
0
Perkasie, PA
the BEST way? Standalone.

The cheapest? SAFC

The next cheapest but better? MAFT-PRO

POSSILBY the cheapest but could be quite expensive potentially: 550's + lex
 

indy_mk3

boost-creep
Oct 15, 2007
100
0
0
33
kelowna
yea but with the lex and 550's your limited to aound 18ish psi so thats why i wanna go maft pro and leave the injectors and pump and see how it is
 

Spudboy

New Member
Nov 25, 2006
4
0
0
So. Cal.
jdub;1030353 said:
First, to make one thing very clear, FC is based on airflow through the AFM. 12-14 psi is about where it will occur on the stock AFM. A Lex AFM will get you to ~18 psi of boost. The BBC DDP and 57 trim CT26 is going to put you at FC at a lower RPM as you discovered.

Question about this Lexus AFM...Do I need or want to get the sensor too?
(the black electrical unit/transmitter) I get conflicting info on this.

Plus...I have, among other things, 1988 Turbo with upgraded 47 trim turbo, K&N filter, FCD, Elect. Boost control, cat-back exhaust, 550cc injectors...et al,.
At some point along these mods, and I'm not sure when, I developed some mis-fire at idle and I assume at speed, along with running very lean according to the smog check guys. I wonder if it all comes down to this stock AFM set-up?

I am considering the Lexus AFM but wonder about that sensor.

I am also very close to getting a AEM EMS (standalone) and wonder if I can successfully map and adjust my air/fuel mixture with that and NOT get the Lexus thing.

My biggest concern and immediate need is to fix that lean and mis-fire problem...whatever it takes. Any suggestions?
 

noel

Uchiha Member
May 5, 2008
512
0
16
Miami, Florida, United States
The LEX AFM sensor is the same as the stock Sensor!! This comes from many sources [someone correct me if im wrong] take ur sensor and clean if not done so already!! How does ur wastegate look? My fuel cut problem was because my wastegate was shimmed!!!:3d_frown:

If u want put the MBC and just turn down the boost for now ...Dont keep fuel cutting its not a good thing

.....just my 2 cents
 

Spudboy

New Member
Nov 25, 2006
4
0
0
So. Cal.
noel;1032821 said:
The LEX AFM sensor is the same as the stock Sensor!! This comes from many sources [someone correct me if im wrong] take ur sensor and clean if not done so already!! How does ur wastegate look? My fuel cut problem was because my wastegate was shimmed!!!:3d_frown:

If u want put the MBC and just turn down the boost for now ...Dont keep fuel cutting its not a good thing

.....just my 2 cents


What do you clean? I take that sensor off and it is just a black plastic vortex generating object, no apparent thing to clean? I guess I'll take a closer look. Is there something inside the AFM metal housing to check?

Waste-gate should be good. Just had the turbo rebuilt by Majestic Turbo.
 

JL7mgte

Member
Mar 31, 2005
77
0
6
Reston, Virginia, United States
Spudboy;1032979 said:
What do you clean? I take that sensor off and it is just a black plastic vortex generating object, no apparent thing to clean? I guess I'll take a closer look. Is there something inside the AFM metal housing to check?

Waste-gate should be good. Just had the turbo rebuilt by Majestic Turbo.

You don't clean the sensor. Don't even look at it funny. It's very sensitive. You just move the afm from the stock unit to the Lexus unit.