if it does a bap bap bap noise it is NOT fuel cut so don't waste your money buying one

so you're saying that when you run 6 psi it doesn't cut at all

but when you run (what psi???) it does cut

what psi are you trying to run?

I normally run 10-12 psi

10-12 is to high for stock running. try running around 7-9 you should get ver minimal fuel cut.

BapBapBap Fuel Cut?
 

Hey Girrrrllll. First off, I LOVE YOUR CAR, secondly,

I am hitting the bap bap bap kind of fuel cut like you explained! PLEASE HELP!
I am at 9psi, Gt35 turbonetics turbo, lexus AFM and 550cc RC engineering injectors, Walbro fuel pump, and Adjustable Fuel Pressure Regulator...
Stock ECU, and I only want 350 Hp. My wastegate wont allow lower boost than 9 psi and I am hitting the bap bap bap fuel cut. I have a EUGO guage to moniter my air flow fuel flow ratios, and it is rich all the time even when hitting fuel cut "bap bap bap" and it bucks the car when this happens, is a HKS Fuel cut defencer safe if i carefully watch the air flow ratios?

If you have all the equipment to monitor your afr, I don't see any reason why you can't use a fcd.

I use one in my vehicle due to my upgrades flowing that much more air that before fcon with my ecu it managed to throw cut in heh.

Just bear in mind that by using the fcd, it won't remove it, it just scales it up further, you can use a fcd and pray that your mods don't go as flowy as mine. Ideally you will need to obtain an aftermarket ecu for the end game.

Atm, with hks fcon, rx7 550 inj, custom intercooler/piping, to4b h trim garrett, 3" exhaust I was pushing 340hp at the wheels on 14.7psi with really really really bad fuel tuning (no fuel cut either), it was tanking in the 9's for afr wot so I now just patter it around town daily driving it till I can give it the ecu it deserves ;)

TBH if you're hitting cut at 9psi, you more than likely have a leak somewhere, double check the basics first as you don't wanna miss something little and have it damage your car. On the other hand, before the fcon I was also hitting cut, but yeah just make sure you've covered the basics.

What is your afr at idle?

The other thing to remember folks that may read this in future, 7mgte fuel cut is very abrupt/violent, it will rev out and then it will be like someone just killed your ignition, it will take a few secs to come off fuel cut, then when boost gets back up to max it will do it again, it's like hitting a brick wall. Make sure you are indeed hitting fuel cut and not experiencing another ignition problem, also the check engine light should illuminate when hitting cut but it can also illuminate when having other problems :p

Do yourselves a favour and check your codes, fuel cut should throw a 34 iirc, abnormal turbocharger pressure.... amusingly enough ;)

Other regulars feel free to correct or add information, it's been a while since I had a stockish car with stockish problems :p

GL

Yep, if you didn't feel sick for a second, thinking you'd thrown a cambelt the first time it happened then it probably ain't fuel cut!

Just to avoid confusion for the future benefit of spainobain, the post you originally quoted said "bap bap bap noise it is NOT fuel cut ". If you refer to it as fuel cut then you'll likely get people muddled up & receive wrong advice... Not saying this to jump on anyones back or anything so don't bite my head off, just don't want you to hurt your engine at all :)

What rpm is your rev counter showing at the time of the problem? IIRC it'll start "bouncing" off the rev limiter actually just before the redline (at least on my JDM dash, not sure on the analogue ones though)...

Rpm Rev When Happens
 

At 4,000 rpm on the rev counter, the problem hits, CEL flashes, and the car bucks (hesitating and hitting a brick wall, then boosting, hitting a brick wall, then boosting again...)
Sidenote: Also the car wants to die if I tap the gas pedal in gear and let off, the rpms drop and the car dies.

My Afr at idle is at 10, pretty rich, I know. The car sputters during acceleration, but idles smooth at this rich ratio. When I tweak the ratios using the SAFC, bringing the afr's to the 12-13's range of the ratio, the car seems to accelerate smoother.
Maybe I need a different piggy back. Which would you recommend being the cheapest way to eliminate the stupid Lexus AFM. Its ugly anyway! Lol

How to tune SAFC with Wideband o2 Gauge?
 

Please answer this,

"How do you tune an SAFC with 550cc injectors and the MAF?"
or
What are the steps 1-10 on how to tune with an SAFC and Wideband?

My car drives like crap hitting fuel cut because I cant get the tune right at higher rpms because I am not going to HOLD my throttle at 5,000 rpms for 20 seconds to get the Wideband o2 gauge to tell me its running a 12 A/f ratio at each RPM.

Problem... When I set my a/f % at a certain rpm on the controller, a minute later, the car evens out and changes the a/f ratio.

example, I set the a/f ratio % on the SAFC to +22%, and the A/f ratio is at 12... a minute later, after reving the engine, the car will be at a/f ratio 10 and extremely rich!

OMG thank you SupraGirl!!! I Love you.
Finally all my final codes are code "34"
FUEL CUT!
YEAH! I have completed the Supra!
HKS FCD, here I come!

http://www.youtube.com/watch?v=RFW3-wl939A