I have an interesting question for anyone expereincing this, my friend has an 87' 7M GTE and when he just starts driving if he goes past half throttle his car jurks and starts to cut like CHUg CHug CHug, and then he has to let off the gas for a while, so what he tells me is that it's "Fuel Cut" fromt he turbo and he has to let it warm up first, also he says it's a common problem amongst the MKIII Supras, someone let me know if A) this is true, and B ) how can it be solved, thanx a bunch your soon to be a supra enthusiest tunner Dieter... :D

whats he running for boost pressure in psi? he should not be boosting untill the engine is warm anyways. however. It doesn't sound like fuel cut to me... when i hit fuel cut its like hitting a brick wall BABAMMM for a second, check enging light comes on and goes out and it runs fine if i pull my foot out of it. It happens about 14+ psi. That sounds like bad wires, or air and or fuel filters? i may even think it could be a bad throttle position sensor or mass air flow sensor? any engene codes present?. its it just when its cold and it runs sweet when its warmed up? could be any number or combination of things but id guess its not fuel cut unless he is over 12-14 psi boost. whats he running for bpu's basic performance upgrades? any mods?

:ph34r:

Sounds a bit like what mine did before I fixed all the vacuum leaks. The service manual says it can be a number of things, but it's namely fuel or air flow problems, or even timing and spark. Fuel cut is nasty harsh, it doesn't cug, it shuts you down pretty much, so i doubt that's it.

kay well basically i think he runs at 14 psi he has about 4000 dollars on the engine in mods but he baught it that way, and i'm not sure what's on it, it works perfectly fine after it's been running a while, and warms up. and it's like a chug that doesn't stop unless he lets off the gas, like the car jurks hard over and over again every half a second, like CHUG CHUG CHUG CHUG... wow yeah i'm good at making car noises *rolls eyes*, yeah he says it's fuel cut but then again my friend hasn't done any of his own modingyet, and he claims to have taking apart and put together his engine , so i don't know if he even has any idea what he's doing, but yeah i think like a leak or air flow problem would be most likely, i'm just curious if it's a common problem and if it's pricey to fix, i'm in canada, so it might cost me more when i get my supra in september, anyways, the feed backs awesome, thanx :D

well... if he's running 14psi he is more than likely hitting fc

and if he can afford $4k into his engine he can afford an aftermarket ecu to fix all his problems ;)

yes, now that sound like fuel cut to me now.... i always backed off after the first one... check my shorts cuz it scares the crap outa me

get the hks fuel cut defender for $99 on ebay like i just installed thanks to suprragirls advice and it works sweet.. thanks suz

Why does fuel cut occur?

it's a safety mechanism .
the computer figures that something is wrong
it calcs the volume of air and the ratio of air/ fuel and computes danger will robinson
toyota figures : just to be safe lets kill the engine for 1/2 a second

haha, I like how you put that. So the fuel cut defender just fools the ecu?

basically yes, i don't have a fco defender but i am close to doing the lexus afm upgrade

the lexus air flow meter and 550 injectors combined fool the FCO
the lexus afm allows 25% more air and the 550 injectors allow 25% more fuel while the computer reads data based off the stock afm and injectors not calculating the extra air and fuel

How much does the Lexus swap usually cost? Where can I find the parts? It sounds like it would be a better upgrade then the fuel cut defender.

try an online auto junk yard for the lexus afm i got mine that way but it was years ago for about 75$
the 550 injectors are everywhere

Also, it's a good upgrade int he end, as it sets you up for even more power. Once you go that high, you still will have to get a FCD, but the fuel cut is a good thing in the end, as it stops overboost if you do something wrong...

So what you guys are saying is the best idea would be to get the lexus air flow meter swap with the 550 injectors and then put in a FCD anyways just to be safe... sounds pricey, but worth it i'll bet, but yeah my friends supra has stopped doing that as much now, as long as he lets the turbo warm up first... anyways, thanx again... :lol:

well, he'll need a FCD to go above...I think it's like 20 psi....can't find the info ATM...too late...

just a reminder to those putting in fcd's

make sure you have the fuel to support the extra boost if you turn it up!!!!

or.... rebuild time!

what is the fuel cut set at? i just got a 87 Turbo Supra and went for a test drive and it pulled alot harder than my friends 90 Trubo Supra. Come to find out the wastegate line was un-hooked. so i put it back on and it topped out at around 8psi