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

[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.

[twenty5psi]

if your going to upgrade to bigger and better anyways later on then now would be the time to try a bigger fuel pump and a rewire since this problem is plagueing you right now..

[unior]

this should be obvious to you but check for big ol boost leaks

my 2g was fuel cutting like a bitch @ 12psi

i had a big leak in my supra smic and the 2g bov was leaking and attributing to it

[tsi_turboawd]

ill tell him look into any intake leaks. He crushed his 1g bov so it shouldnt be leaking out there to cause fuel cut.

..and i told him to upgrade his fuel pump to 255 anyway

[TalonTSi-AWD91]

Hey everyone, I'm having a problem with fuel cut, but I don't think I should be. When I'm driving as soon as I hit about 5,500rpms the car hits fuel cut. Also if I just cruise or let off the gas the car feels like it's missing or it's getting like a 50rpm idle surge I guess. Problem is I'm at stock boost right now. The only mods I've done is an upper and lower intercooler pipe, K&N, and removed air can. I've changed the TPS, spark plug wires, spark plugs, tried a different MAS, and checked for leaks. I did find a decent leak, fixed that, but the problems still there after everything. I've checked for error codes and get none at all. When I changed the spark plugs, they were white, which I don't know if they should have been or not cause they've only been in the car since january if I remember right. I'm going to check the coil pack and CAS just to be sure, but what else could be the problem?? The car was perfectly fine, then I changed the oil in it, car was still running perfect. A few minutes after I changed the oil I went to the car wash to clean the car up and it was fine on the drive there. After the car wash, the car seemed fine till right before I got home and I started noticing the missing when letting off the throttle. Didn't drive it the next day, then the day after when I drove it, this all started. Also, I don't know if it'll make a difference, but it'll buck at around 5,500rpms anytime, when the cars cold or hot, but the missing doesn't happen till after the car warms up. Thanks for your help, and sorry it was so long, but just wanted to make sure I covered everything.

[EHeye]

i dont think its fuel cut bud, at 5500 rpm is when the stock 14b drops off, ie no power.

[TalonTSi-AWD91]

It's not like I'm just losing a little power, the car feels like it's hitting a brick wall.

[EHeye]

yah bsically thats what it feels like, nothing left, thats cause you think about it your going from boost to basically nothing, try rewiring the fp and test the voltage through your car, your caps may be leaking a bit making voltage off taking alot of power away from the fuel pump.