Fuel Cut: What is it? How do I fix it? [merged]

[Slanted J]

All fuel cut threads are combined here.

I've tried doing a search but to no avail.

I was just wondering what Fuel Cut is. I've heard it tossed around alot, but do not actually know the details behind it. And, naturally, I can gather that its when the fuel is cut off, but when and why.


Thanx,
Jon

 

[DevilSperm]

sounds to me like fuel cut...mine would do it really bad if it was under 10 degrees...being that cold you are cramming a lot of air in the cylinder

 

[noreaga0221]

fuel cut is not caused by fuel levels, lack of it or too much. its caused by maf over run. when your big turbo sucks in too much air the ecu gets scared and helps the defenseless engine by shutting it down for a second or so. al blaha mas, 2g mas's both help cure fuel cut for 1g's expierencing it. al blaha mafs help because they trick the ecu into seeing colder air so its expects to see more air. and 2g mafs are just bigger.

 

[bobo2986]

it typically happens when it is really cold outside and when I am getting on the throttle but not always

 

[boostineklipz]

stock turbo, Apexi N1 downpipe N1 catback exhaust, greddy intercooler pipping, Bitz turbo timer, greddy type S BOV, and injen intake...

Do you have a boost controller?? If your getting fuel cut all the time, that means you might be running alot of boost for some reason. I hope you have a boost gauge. How much boost are u running????

 

[sential]

I cant tell if I'm hitting fuel cut or if my plugs are bad. Do the two problems feel any different?

 

[dave99gst]

if it was fuel cut .. you would know it- - its like all of a suden nailing a brick wall. plugs is more of a miss/studder

 

[sential]

well I hate that answer cause that's what everyone says. I know that I've hit fuel cut before, and it sucks. But don't bad plugs create the same effect. They go out, you dont get spark, and bam... your car studders/hesitates/cuts out... whatever, I just can't seem to tell the difference

 

[dave99gst]

improperly gap's plugs -- or fubard plugs may only miss while under load/boost- and its not the same as fuel cut -- if ya want to know what its like.... have somone drive yer car -- and have then launch the shi* out of it .. all the mean while you try to hold your face around 8" away from the windshield..then when the drivers gets in say 3rd gear...( stilll floor'd ) they can let off the gas ( go from floor'd to nothing ) at a time when you aint ready for it.. you will prob slam yer face into the windshield. fuel cut is the same.. ECU lets off the gas when you aint ready for it. aka - cuts the fuel .. plugs are much more bearable.. more of a studder/stumble/ miss

 

[sential]

thanks for the reply, It sounds like its fuel cut.

 

[GSX90]

Originally posted by sential
thanks for the reply, It sounds like its fuel cut.

Can you get yourself a fuel cut defenser? What kind of EGTs you seeing?

 

[jretta91]

actually, it could very well be your plugs... my car was missing/cutting out, but only under full boost.... i changed the plugs, it ran perfect... the plugs aren't providing a strong enough spark at high rpms, so you'll just cut out.... NGK's are the plug to go with

 

[MidnightRun]

Ok, well I solved one problem, only to have another arise. I had been cutting out at roughly 5900rpms, which really felt like violent fuel cut. I couldn't figure out the problem for the longest time, as I am running a 2g MAS and a 16g @ only 14psi. Well, I went to do some diagnosing one day in hopes of finding the solution and I caught a break. I noticed my boost gauge was holding boost fine until it spiked to 21 psi when I hit 'fuel cut.' Well, I ultimately found a tear in the hose that goes from the wastegate nipple to the Profec B 'control box.' It was at the very end on the wastegate side, so I simply cut that small piece off, reattached the hose, and went for another run. YEA! No more fuel cut, but now I'm getting steady boost creep. It'll hold fine until about 5000rpms, then creep to 21 by 6000rpms. I tried adjusting the Profec B to no avail, same results. Any ideas why I would be getting creep now, and not before? I never has a problem with boost creep or fuel cut before this, and I haven't really changed anything in my set-up from then to now! PLEASE HELP!

 

[NewB2dsm]

Before you install the t28 get a new fuel pump! ALso you wont hit fuel cut on the t25 it just cant flow enough air. My sugestion is to put on the t28 and start from there. Its probably too rich up top, do you have a A/F or egt ? What do those say?

 

[turbokidd]

Hello! I have a slight problem that maybe you all can help me with; I have a '99 Spyder GST and have recently begun addind some modification- basic bolt on stuff. Today I installed my new Greddy IC pipes and Greddy BOV. It completely transformed the car, pulling REAL, but now I have what feels like fuel cut!

Besides the IC pipes and BOV, I have a Greddy Evo exhaust and air filter. THAT'S IT! The only other thing that I have done is a B&M shifter, bushings, and strut bar- none of which would affect fuel cut.

HELP!!!

 

[AW4G63]

You could just be running too lean, its maybe pulling your timing on you. What kind of gas are you putting in the car? Do you have a boost gauge?

 

[turbokidd]

I believe I answered my own problem- the line going from the intake manifold to the BOV was torn at the end, and not sealing.

Two questions- My "Check Engine" light is on now- can I reset it, or do I have to take it to the dealers?

Also- do most people tie the second smaller nipple on the Greddy S-BOV to the wastegate line or leave it alone?

THANK YOU!

 

[TalonRacer18]

and no, DSMlink won't get rid of fuel cut, however it will allow you to tune your car so that you can work around it personally, i'd leave the fuel cut as it is. it's there for a reason.

The dsmlink does take the fuel cut off of the ecu. If you read on their website you would know that. Why would you want it on there still? If you plan getting a dsmlink, then you better damn well be sure to tune a car, and know alot about it. It is there for a reason, but if you plan on making more than 250 hp, you would want it gone.

 

[coltboostin]

just got done witht he install of the 4G63t in the 93 colt. Funny thing I am getting fuel cut at 14psi now. I was running 17psi on the laser it came out of and 16psi in the first colt (89) with no problems. Any sugjestions? I do have a hacked MAF and a full 3 inch intake. Other than that car runs fine.

 

[out there]

ok, so i was out driving today, hadn't driven the car since... well, last night. anyway, i floor it in 2nd just over 2k, i hit 15psi... and bang! sounds like the car backfired... but there's nothing wrong with it, it hasn't ever done this, so i'm thinking it's fuel cut. is this possible? to hit fuel cut at 15psi when it hasn't ever done that? i've hit 15psi in every gear and kept it there (or really close) until redline in gears 1-3 with nothing like this. my passenger gets this panicked look on his face, and i say "so that's what fuel cut feels like" because that's what it seemed like. any thoughts?

 

[DSMeclipse4G63]

yes fuel cut is when you are flooring it and are pinned in the seat and then all the sudden you tase steering wheel that you just ate. My gauge read 13 psi when I hit it the first time. Thats because the boost builds too fast for the gauge to put out for you to see. My mbc is just starting to f*** up so when I floor it I either get about 13-14 psi and great acceleration or I get fuel cut at 4k rpms or less.

 

[out there]

ahh.... so fuel cut isn't all the time then? just occasionally the ecu will pick up on it, or just occasionally the acceleration is just so and the ecu decides to cut it, right?

 

[tsi_turboawd]

I am posting this for a friend of mine who also has a '91 TSi AWD. He just got it a few weeks ago and has been giving him the same problem till now. You guys can probably help him out.

He hits fuel cut at higher rpms around 5k or so. We tried at both 10psi and 15psi setting on the MBC and same result. The compression on all cylinders was only around 135psi according to him. He says he could redline BUT only being LIGHT on the gas pedal. I test drove it and when I floor it all the way it hits fuel cut not even anywhere near redline.

Heres what has been done as far as i can remember:
-replaced fuel filter
-new T-belt
-spark plugs
-magnecor wires
-injector cleaner additive
-MAS
-ECU
-FPR
..none of those stopped fuel cut

I was thinking about the stock FUEL PUMP being shot and not supplying enough fuel at high rpms. what do you think is wrong?

 

[tsi_turboawd]

anyone??

 

[Thebeast431]

Try removing the lower honeycomb, otherwise it is fuel cutting for a reason and get a Pocketlogger and fine out whats really going on. Does he have a 14B or 13G

Travis

 

[tsi_turboawd]

He has a 14B. We tried it with the lower honeycomb on and off and it doesnt matter somehow. I dont think he has access to pocketlogger. But ill tell him to look into getting one. As for now we're just trying to find out the possibilities.