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

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Slanted J

Supporting VIP
131
3
Feb 19, 2002
Janesville, Wisconsin
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
 
The tranny was just rebuilt and put in a week ago. We might have noticed the to bearing, but it is definitaly worth checking.
 
okay I have a 98 GST 5 speed. it has a big 16g turbo and a K&N open element.. during the days I have no problem running high boost (17) but at night when it is low 70s high 60s at high boost it is hitting a fuel cut or something.. because it will pull hard - cut out - pull hard - cut out. until I let off the gas I know this is caused by the colder air being denser and letting too much air past the MAF sensor. but how can you fix this problem?? I know one solution it switch it over to a Chevy style but that is not a option right now.
 
bad the motor basically cuts out completely for a second then comes right back.. kind of like a car when it hits a speed limiter
 
I suggest setting your boost level at night so you don't hit cut and wait untill you can run a GM mas translator.

That way you won't break anything before then. Like melt a piston or valve.
 
I had the same problem, no fuel cut when it was warm but I was getting fuel cut by 5000 rpm's in the morning, this was at 16psi. I turned the boost down to 12psi, I got a pocketlogger and found out I was also running very lean.

Once you get more fuel, via injectors or turning up the fuel pressure, you can use the MAFT or SAFC to delay when fuel cut happens. The MAFT also has a function to turn fuel cut off, but in my opinion this is not a good idea, its there for a reason.
 
I'd get rid of fuel cut if possible.


If they were thinking they would have included ignition cut instead or with fuel cut. A hard fuel cut is a bit harsh. Soft ignition like a stutter box would be better to protect from over run.
 
I forgot to mention the boost control is coming via Profec-B


okay how much would the GM MAS translator cost... I can get the meter from a local junk yard for free.. but how much for the rest of it.. I have never seen this anyplace.

I do not want to cut up the factory MAF because of fear that it would not run right or it wuld not seeall the air and go lean..

adding fuel would be safer for the motor, but it would not help with the cut out..
 
Originally posted by myblack98gst
I forgot to mention the boost control is coming via Profec-B


okay how much would the GM MAS translator cost... I can get the meter from a local junk yard for free.. but how much for the rest of it.. I have never seen this anyplace.

I bought mine from www.dejontool.com

Originally posted by myblack98gst

adding fuel would be safer for the motor, but it would not help with the cut out..

Yes it will, when using both the maft or the safc you program in what injectors your using. Both these devices tell the ecu that you getting less air to compesate for the bigger injectors, this cause's the fuel cut to happen latter. Do a search a read up on both these devices, you'll see what I'm trying to say.
 
my mods are in my profile. i am currently running 10lbs of boost on 94 octane. i kno i have a blown head gasket but i am also gettn fuel cut.
is this also a result of the headgasket. i am goin to replace the gasket next week but i was just curious if that was the problem. thanks
 
I have the 1.0 ver Maf translator with a 3.5" Maf. I've been driving with it for a month now with no problems until yesterday. As soon as I boost over 10psi I get Karmen of 2400 at 5300rpm or 1800K at 4800rpm and fuel cut.
I haven't changed anything. There was a bad rain storm when this all starting happening. Although the Translator didn't get wet. I can't figure it out.
Anybody?
 
Ok, i gave my car an oil change yesterday to make it happy. Took it out, under somewhat hard throttle it hits a brick wall. Here is whats stumping me. there is a low kina moan coming from the motor/exhaust? when it starts to die out. Im going to replace the fuel filter as it looks like the stock one from 92 and see if that helps. Anybody have any ideas? I dont have a pocket loger just a HD intake and no air can. Ill pull it and check to see of the wg acutator is working right or if the nipple is pinched close. Any ideas:confused: :talon:
 
i know how to stop it get bigger fuel pump and injectors, but can i just get a 255 walbro and it will stop fuel cut or is it the injectors doing it or is it both cause i only have money for one of them right now and i was wondering or is it part of the ecu doing it was wondering if needed bigger fuel pump or bigger injectors first or both :talon:
 
How much boost are you running? After so much boost the ECU will cut your fuel. I've hit fuel cut at 15psi on cool days. You can cure it somewhat by removing the lower honeycomb on your MAS since you are running a 1G. Just be warned that after 15psi this mod might cause you to run too lean. An SAFC will fix this.

If the problem is that you are not getting enough fuel, you can go with the Walbro 255 low pressure unit. I wouldn't run the high pressure unit unless you get an adjustable FPR.
 
like it said i hit fuel cut at 15 psi, i dont understand this its the first itme it has happened and i would like to know why if anyone had any ideas let me know, i have a hard wired fuel pump, and everything elce is pretty much stock i have my mods in my profile. thanx
 
....what a question. For one thing, you havent posted nearly enough information. We would need to know all of your mods, what octane you use, what elevation your at, and about what temperature it was outside. It is common for people to hit fuel cut at 15 psi if all they have is a fuel pump. If it is colder out than normal the air is denser and you need more fuel for the denser air, therefore your injectors have to work harder and at 15 psi they were obviouslyt maxed out if you hit fuel cut. Only way to keep an eye on when you will or wont hit fuel cut is to monitor your injectors impedance, and the easiest way to do that is with a pocketlogger. Pm me if you want more info.
Hope this helps you out bro.
 
did you hack the aircan? after doing that i never hit fuel cut again, once was enough :barf:
 
Even when Ihave the smallest boost leak, I hit fuel cut. Check all your intercooler hoses etc for leaks.....everytime I hit fuel cut I always check my upper intercooler pipe connector (one that goes to the intercooler) and it usually has a slit or cut in it from the clamps over time. I change the connector and it is usually all gravu again.
 
i am not a newbey at this, if you will read my post i said i have my mods in my profile, and it was a normail day out it was kinda hot actualy, and i am at sea level, i have no boost leak, i have already checked my intake system like 5 times, i reset the ecu and it has not done it since.
 
People *might think that you are.
Now on the question at hand.
How do you know you have no boost leaks?
Do you have a pressure tester?
Do you have a federal ECU or a Cali ECU,and does it have an EPROM?
And like the rest of the brothers asked, what octane are you using/ real boost level (Not stock guage).

Now, when you answer those questions, you can think about a TMO Eprom/Mistu-specialties off Ebay eprom chip to eliminate fuel cut from the ecu entirely. But that would nesesitate an EPROM ECU, so if you dont have one, get one.
to see if you have a cali/federal/EPROM ecu go to www.vfaq.com and use the ecu reference page.
Just because it hasn't F.C. since you reset the ECU, it doesn't mean it wont do it again. Read up, do some homework, and then get your fuel cut problem fixed so you can eat some civics!

:thumb: :dsm:
 
actualy i was considering getting a tmo chip, but i heard that tmo closed, anyone know where i can get one at a good price.i am not runing a stock play toy, i do have a real boost gauge, octain is 93 i think whatever the highest octaine is around here, and i hit fuel cut again tonight, it is really starting to piss me off i guess i will try reseting my ecu again. i think i really need to invest in a loger too. and the reason i put this in here is it is general/newbey form, i figuerd this was a pretty general question, not to tech envolved, thats why i posted it here.
 
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