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

 

[Judacoth]

Well... 1st off, Did you know you have the incorrect injectors in the car??? Also the pigtail connectors are all the wrong type and are brittle. The car takes Bosch and Lucas style injector connectors. Also on of your injectors is leaking, ie: the fuel smell. Still the problem is definitely heat related. Your cam / crank angle sensor may also be a culprit.

 

[steve]

What you described and the 41 error pretty much nail the problem down to a injector wiring or faulty injector. It's not uncommon for the coil to open once the injector gets hot but work when it's cold. It's also pretty common for the harness to break once the insulation gets old and brittle.

My original #1 injector failed that way and the car would buck once the engine bay got hot.
It would measure fine cold but If I measured it when the problem was going on it would be open. I narrowed it down to #1 by disabling the injectors with the datalogger to see which didn't make a difference when disabled.

What's an injector relay. The injectors connect to the MPI relay for power along with most of the other stuff under the hood.

Steve

 

[4g63telantra]

Just wanted to know do talons/eclipses need to run some kind of Electronic Fuel Cut Defender?

I know TurboSmart makes a Electronic Fuel Cut Defender and i can get good deals on one, so I wanted to know is it good to get one or just a waste of money? btw ill be running DSMLINK if that helps

 

[VelocitàPaola]

FCD's are mostly used in N/T cars when converting to turbo. The MAF sees more than usual amounts of air flowing into the engine and takes "emergency measures" in order to stop it.

Not to say it can't happen on a 4G63 Turbo, you just need to be running much more boost than what the car was originally designed to handle, or have a really sub-standard fuel system to see it.

I'm not sure what kind of Talon/Eclipse you're referring to, since there's the 4G63 N/T, the 4G63 Turbo, and the 420A, so the definitive answer is dependant on that.

Refer to this FAQ by crankbender for more information.

http://www.dsmtuners.com/forums/showthread.php?t=186971&highlight=fuel+cut+defender

 

[bluedotfatcap]

the defender doesnt actually cut it like the name says it jus makes it higher...

 

[VelocitàPaola]

the defender doesnt actually cut it like the name says it jus makes it higher...

An FCD keeps the voltage emitted from the MAF below a certain point (usually under 5V, at around 4.7V), anything at or above what the FCD is set at will usually send a signal to the ECU, telling it there's too much air, and thus causing fuel cut.

 

[JoeWagon]

Fuel cut electronics cap an airflow signal, so if you flow more air than the ECU "sees", you will be running lean. Skip these bullshit devises. DSMlink will do what you need, anyway.

 

[PhoenixRPR]

Thanks

 

[srGS-t]

hey everybody ok i have a 95 eclipse GS-T and all i have done to the car so far is rims and Exhaust system and intake and a greddy type-s blow off valve.

ok after i had put the intake on and i took it for a test drive and 1st gear was fine and then 2 gear was ok till i hit 4,500 rpm and the the car jerked really bad and it felt like hiting a speed bump at 120

any way it dose that threw each gear but not 1st

i put my stock air box on and it was fine i think its fuel cut but i havent checked the car for a boost leak yet case im geting a new turbo big28 and my car is all over my floor

but i cant see how it would only do it at that rpm if it was a leak case it runs fine if i run it hard and dont let the rpm drop under 4,500

 

[killakev805]

hey everybody ok i have a 95 eclipse GS-T and all i have done to the car so far is rims and Exhaust system and intake and a greddy type-s blow off valve. ok i had just got the intake on and i took it for a test drive and 1st gear was fine and then 2 gear was ok till i hit 4,500 rpm and the the car jerked really bad and it felt like hiting a speed bump at 120 any way is dose that threw each gear but not frist and if i not really on it and only 50% gas it wont do it so i out my stock air box on and it was fine i think its fuel cut but i wanted to ask thanks for reading

I can't understand what you are saying

Are you saying you put an intake, exhaust and a BOV on it and it hit fuel cut, so you put the stock air box back on and now it doesn't hit fuel cut?

If that is the case, I would start by checking for boost leaks, now that you have a free flowing system a boost leak will be more noticeable.

p.s. please try to use proper grammer next time.

 

[knighteclipse1]

any time you free up the breathing of a turbo, the boost will increase, fuel cut will happen when the ecu sees that and tries to compensate, if your still using the stock boost gauge, then get a aftermarket gauge b/c the factory gauge sucks and is really not what you need to be looking at when figuring your boost...get a gauge and let us know what its reading...more then likely you need to limit the amount of boost your turbo is making. I had a similar problem. problem solved...

 

[dwc4g63]

i have a buddy with a 95 tsi that was having the same problem as you..he got a new intake, boost controlller, and upic and installed it all himself, then calls me the next day cause his car is running like crap (same symptoms as you) he swore he had everything from fuel cut, to a leaking bov, to phantom knock..instead of just going back and making sure everything was installed correctly. his problem ended up being that he kept blowing off his upic pipe everytime he went above 4k (failed to mention this till i drove the car) yeah its possible you have a more complex situation (fuel cut etc) but its more probable that you missed connecting something, are all the intake lines/ports connected or blocked off as they should be? is your maf sensor on good and does the wiring look solid? is your air filter on snug? is your bov installed corectly? i know you said your car is all over the floor, but when you put it all back together make sure everything is sealed, tight, and perfect. and if you have any questions as to something being done right just ask us. if you dont have a boost controller, stock boost should be around 12lbs, and fuel cut usually doesnt hit untill 16-18+lbs (correct me if im wrong) and i dont think an intake is going to net you that much boost gain by itself, mine only gained me like 1 lb 1.5 tops, so id say its more likely something ON THE INTAKE is/was not connected correctly.good luck and let us know.

 

[JST2FST]

if you dont have a boost controller, stock boost should be around 12lbs, and fuel cut usually doesnt hit untill 16-18+lbs (correct me if im wrong) and i dont think an intake is going to net you that much boost gain by itself, mine only gained me like 1 lb 1.5 tops, so id say its more likely something ON THE INTAKE is/was not connected correctly.good luck and let us know.

This is true, but you have to remember that he also added a Type S BOV. If his old BOV was leaking then it is very possible that the Type S would raise his boost which could be causing the fuel cut. When i had my stock BOV i was at 15lbs, after i added the Type S my boost jumped to 20lbs. So it is possible that by adding the BOV you might have raised the boost up. I also agree that you might also want to make sure every thing is connected correctly, as that could also cause your car to run like ass.

 

[Patterson]

p.s. please try to use proper grammer next time.

...exactly

 

[srGS-t]

Ok sry about my bad grammar I haven’t had much sleep in the last few days so just forgive me on that.

Ok well I have talked to my friend that tunes cars and he is pretty sure its fuel cut because it only happens with the after market intake on. So if all that is true then what do I do now. I have looked at dsmchips and they have a EPROM for my car that would stop fuel cut but is that a good idea. I mean im about to have more air flow when I get this new big28 turbo.

So if yall could please help me out im new to dsm's and I just want to get my baby working again.

 

[oldman]

Ok well I have talked to my friend that tunes cars and he is pretty sure its fuel cut because it only happens with the after market intake on.

Does your friend work specifically on DSMs? There is just no way you're hitting proper fuel cut with stock fuel system, stock smic and T25, you're simply not flowing enough air or fuel. Either you have boost leaks, defective mas or you're not hitting fuel cut. Post back after you perform the leak test.

 

[srGS-t]

Ok like I said before my turbo failed and is off the car so. I cant perform a boost leak test but I need to know when I get the new turbo on that it wont mess it up if it has a boost leak and I need to know so badly because I cant afford to mess this up and I cant take this to a tuner shop case im in AL and there few and far around here please give any advice you can p.s. that was a long run on sentence but work with me I just need some help. And no he dosent work on dsm but had this problem in a 240sx

 

[kylehlub]

I am having the same problem with my gst. My car also dies around 4 rpm but it doesn't jerk at all, it just dies quietly. I check for leakage and my manifold gasket was a messed. Also I needed to retighten my turbo, which was leaking oil. I replaced that gasket and all other gaskets from the manifold to the muffler. The car runs a lot faster but is still getting fuel cut. There is no other leakage in the car except for my muffler, which has a couple of holes. I am waiting for my replacement to come in. Is a coupe of holes in the muffler really going to cause fuel cut or is it something else?

 

[Defiant]

any time you free up the breathing of a turbo, the boost will increase, fuel cut will happen when the ecu sees that and tries to compensate,

Kind of. Fuel cut is what happens when the intake starts flowing "too much" air (as determined by ECU parameters, not unlike the way the stock boost gauge is driven), regardless of boost levels.

 

[srGS-t]

Well how can I tell the ecu that the car can handle that much air???

 

[94awdcoupe]

Well how can I tell the ecu that the car can handle that much air???

get an S-AFC.

you need to make sure you have an aftermarket boost gauge in your car. you have absolutely no idea how much boost your running.

 

[knighteclipse1]

Kind of. Fuel cut is what happens when the intake starts flowing "too much" air (as determined by ECU parameters, not unlike the way the stock boost gauge is driven), regardless of boost levels.

I have hit fuel cut after my 3 inch turbo back was installed with no cat. free breathing and all...scary feeling. but my boost went totally crazy. once i was able to get the boost under control. no more problem. You really need a aftermarket boost gauge.

 

[97GSX-509]

Even with an chipped EPROM and a S-AFC, you may still have problems with fuel cut. I am fighting it now....running about 25lbs of boost with an EPROM with KeyDiver Stage 3....

I am still so confused as to why I am fuel cuttin. Here are my mods....maybe somone has an idea....? Thanks


97 GSX -

MODS:


PTE 50 Trim Turbo with less than 10k

HKS 40mm External Wastegate Vented to Atmosphere

HRC 3 inch Eliminator Downpipe

HRC upper intercooler pipes with HKS Super Sequential BOV with recirculation pipe

SPEARCO 31.25x9.25x3.5 inch with 2.5 Pipings

HKS 3 inch Super Dragger Full Catback

3 inch Test Pipe

NGK BPR7ES Spark Plugs

Magnecore Performance Spark Plug Wires

DSM PERFORMANCE 3 Inch Intake Pipe

DSM PERFORMANCE Intake Filter

INJEN Fuse Box Cover (Polished)

DENSO 660cc Injectors

Walbro 255lph HP Rewired fuel pump

B&M Adjustable Fuel Pressure Regulator

2G Exhaust Manifold Ported Matched for Turbo Inlet

HKS EVC EZ Boost Controller

HKS Turbo Timer

APEXI Super Air Flow Converter fuel controller

ACT 2600lb Xtreme Clutch Kit

ProStreet Flywheel

3 Gauge Full Replacement Pillar with

AUTOMETER Boost Phantom Gauge,

AUTOMETER Air Fuel Phantom Gauge,

AUTOMETER Egt Phantom Gauge

TEAM RIP ENGINEERING EGT PROBE

Eprom 95 Ecu w/ Stage 3 KeyDiver Chip

POCKETLOGGER Software/Program

PALM PILOT to operate software and tune car

PAINT MATCHED Valve Cover



EXTERIOR:

VIPER YELLOW Paint Job

97 Front Bumper Modded to fit Spearco Intercooler

BLITZ Low Side Skirts

BLITZ Rear Bumper

Painted Matched Center Tail Light

Door Holes filled where the door caps used to be

SYLVANIA SILVER-STAR Head Light Bulbs (Greater Night Vision)

Cleared Out HeadLight (Black-Housing Look)

TINTED WINDOWS

CLIFFORD 100 Auto Security Alarm



Suspension/DriveTrain:

18x8.5 GEWALT EVOLUTION 3-Piece JDM Rims with 225/40/18

ENERGY SUSPENSION Strut Bushings

KYB AGX 4 Way Adjustable Struts with

EIBACH PROKIT SPRINGS (1.3 inch all around)

BREMBO ROTORS - Front: Cross Drilled & Slotted Back: Slotted

AXXIS METAL MASTER Front Brake Pads

EXTREME MOTORSPORTS Short Shifter

Rear Strut Bar

Metal Bushing shift plate bushings

Metal Bushings for shifter cables

CAMBER KIT ON REAR



INTERIOR:

SONY CDX-90 CD Player

ECLIPSE 3-Way 6x9 Speakers

SONY 4-Channel 500w Amp (Custom Mounted)

Punch 250w Amp

2 Ten Inch JL W3 Subs with Box

ACOUSTIC Crossover

PAINT MATCHED Gauge Cluster

AC AUTOTECHNIQS Reserve Indiglo Gauges

Original brown/black interior swapped to grey/black



OTHER INFO:


MOTOR REBUILT AT 50k

TRANSMISSION REBUILT AT 65k

 

[oldman]

^^^^ Possibly boost leaks. Didn't you remove fuel cut with the keydiver stage3 chip?

 

[KuZo]

boost leak or you're getting so much knock you think it's fuel cut. I never had a problem with fuel cut mysteriously coming back on my keydiver chip or DSMLink at 23psi.