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

 

[slow4G63]

if you turn down your boost that should help it some! I just got a 2.5" turbo back to race pipe, then 3" back exhaust with a 4.5" tip... now i get fuel cut!! Just got my walbro 255HP fuel pump in, installing that tonight!

 

[jdm4g63]

One of my favorite magazines is import tuner and it has been since the did a power pages special on the 1g eclipse. They did the exact same thing that you did. I believe the mods were limited to hyperground wires, air intake, and cat back for round one. Then round 2 was the 3" apex dp, 255lph fuel pump, and hks fcd. These were the only mods on the car. The car went on the dyno and did just fine. You should be able to get away with the stock injectors for a while longer, probably until you get a new turbo or want to turn the boost up past 14psi. Actually that was the next series that they did on the car 550 injectors, safcII and boost control.

 

[karbon]

I wouldn't add the fuel cut defenser as a band-aid for fuel cut. If you're getting it in the first place, something's wrong with your setup, or your tuning. It's there from the factory for a reason. But like the guys before me said, we need some more info to help you with the fuel cut problem.

 

[jdm4g63]

His setup is fine, but he has no tuning. That is why he would use the hks fcd. However I should have added that the once he has the afc then the hks fcd is no longer needed.

We could use some more info on your project as karbon said. When are you planning to get the safc? If you plan to get the safc anytime soon, just bypass the fcd. The fcd is a temperary fix for someone who is probably around your stage of a project and cannot/doesn't want to get the afc yet. I can imagine that you are having some problems with fuel cut and probably a good boost spike with your current mods. You may even see 17psi sometimes (I used too) but without the means of delivering adequate fuel to support that. I did not look at your profile but if you don't have one you need to get a mbc and set it to 14psi until you uprade those injectors. (You should have a boost gauge by now, if not check out summit racing for a good price)

To sum it all up, only use fcd if you want to make your car drivable for a while until you can get your safc as there is no reason to have both at the same time. You can probably sell the fcd for around $50 on ebay.

 

[1bad92awd]

The best upgrade you can get to help your fuel cut situation are bigger fuel injectors. I would imagine the fuel cut defencer would work fine, i havent heard a lot about it though, so let me know how it turns out for you.

 

[oldman]

if you turn down your boost that should help it some! I just got a 2.5" turbo back to race pipe, then 3" back exhaust with a 4.5" tip... now i get fuel cut!! Just got my walbro 255HP fuel pump in, installing that tonight!

No He needs a tuning device to run a 2g mas in a 1g period. Turning down the boost will only help him with the fuel pump and and stock injector issue after tuning.

If you're still set on running it the way it is go right ahead, I think I've said enough.

 

[InjenTalon96]

well i lowered my boost all the way down, to who knows what, its not studdering or anything anymore, but still lean, im not driving the car at all thou, i just took it down the road. i just cant wait to get my afc, walbro 255 hp, and my 550's

 

[Sil-Eighty SE-K]

wello 1st of all those engine bay shots are my other car....240sx

secondly all i have is a 3in dp (N1) and 3in catback (n1). And i opened up my intake and HKS SSQV BOV. I have the FCD already and the fuel pump and a boost gauge....i just havent put them in yet. So all i know is that my stock gauge maxes out (past 14psi) and i eventually hit the fuel cut. I have yet to find time to install the boost gauge, I have no boost controller so there is no way for me to back down the boost. I hear that the FCD may levekl it out at 15psi which ill be more than happy with. BTW i still have the 14B...and the safc wont be for a while....i need a clutch and manifold/02 housing SOON....

 

[midnght]

You might be maxing out your IDC. I do not and would not ever suggest a FCD on a DSM. Fuel cut is there on this car to let you know you are surpassing the safe limits on your fuel support.

That temporary fix could and can cause a permanant problem.



AT YOUR OWN RISK

 

[Defiant]

wello 1st of all those engine bay shots are my other car....240sx

Very nice, but not allowed. Sorry.

 

[blcknspo0ln]

I wouldn't add the fuel cut defenser as a band-aid for fuel cut. If you're getting it in the first place, something's wrong with your setup, or your tuning. It's there from the factory for a reason. But like the guys before me said, we need some more info to help you with the fuel cut problem.

agreed. DONT put an FCD in your car..

if you're hitting fuel cut at 14 psi on a fuel pump, i'd check for boost leaks. no way should your car be doing that. if you absolutely MUST be on the throttle all the time, i'd suggest finding away of putting your cat back on the car. in some cases the added backpressure will ease boost creep.

are you venting that SSQV?

 

[slow4G63]

97 eclipse gst
only mods I have is exhaust, fuel pump, short throw shifter, turboxs rfl bov

this has happened to me about 5 times now... When I punch the gas and get up around 4500rpm's my car like jerks(makes a loud noise near the engine, like at the manifold or something), it makes the car like choke kind of, scares the shit out of me.... it just started to happend after the exhaust was put on about 2 weeks ago...

so I thought it was fuel cut and that a new fuel pump would fix it. Bought a walbro 255HP fuel pump and installed it last night. Still the same thing! Anyone know what this could be?

specs on exhaust:
2.5" downpipe to testpipe (no cat), 3" back to highflow magnaflow exhaust with 3" tip.... could this be doing what it's doing because of no cat.??

 

[fish3rboi]

Yes it sounds like fuel cut. Imagine hitting a brick wall while you are at WOT... I am assuming stock injectors, stock boost, and no tuning equipment correct?

 

[EclipseOwner95]

I don't see you having a boost gauge as one of your mods, installing a bigger exhaust may cause the turbo to creep up to higher boost levels, hence causing fuel cut.

 

[Nelsons91AWD]

Yes that sounds like fuel cut, its a scary thing.

I had it when i first bought my car. Went through replacing a bunch of parts.

then finally found it was my ECU causing the problem.

Replaced it and works like a charm.

Might not be the case on your 2g.

 

[L2RTSiAWD]

I suggest getting a boost gauge so you can see what is happeneing. That should have been your first mod.

 

[slow4G63]

I have a boost gauge not, just not hooked up, I am going to do that tomorrow most likely... Figured I'de put it in when I hook up my dual stage bc... the thing is though, I haven't put the boost guage in yet because it should still be at stock pressure. I have not did anything yet to the motor really other than the bov and fuel pump. the exhaust caused the problem, it had to of! it has nothing to do with my boost. anyone have an idea of what i should try, maybe doing something to the ecu?

 

[CyberEye]

I have a boost gauge not, just not hooked up, I am going to do that tomorrow most likely... Figured I'de put it in when I hook up my dual stage bc... the thing is though, I haven't put the boost guage in yet because it should still be at stock pressure. I have not did anything yet to the motor really other than the bov and fuel pump. the exhaust caused the problem, it had to of! it has nothing to do with my boost. anyone have an idea of what i should try, maybe doing something to the ecu?

Are you not reading the replys? or are you just ignoring them. Your bigger exhaust will/may cause boost creep. Which basically means your boost will creep up past stock levels. So really, you did do something that effects your boost.

 

[Omega]

Put the boost gauge in. Put the boost gauge in. Put the boost gauge in.

Did you put it in yet?

I am with EclipseOwner95. I bet you are creeping now. Don't put the MBC in yet, since you have no idea what you are running now.

The amount of boost as everything to do with the exhaust. If the WG can't get rid of enough exhaust going through the turbine, the boost pressure will rise up (also known as creeping). This usually happens when you remove restrictions from the exhaust (sound familiar?) So, you now have the turbo sucking in a WHOLE lot more air that it used to. The ECU is fine with that as long as it measures less that X amount. Once it goes over X amount, it steps in and goes "whoa...hold on, this isn't right" and shuts off the injectors (fuel cut).

Does that make sense?

Please, put the gauge in. Then tell us what it reads.

 

[oldman]

You need to take other's suggestions more seriously, especially when every one is saying the same thing. Hook up the boost gauge now so you can tell where and how you're boosting. You may either have boost creep or a bad boost leak.

 

[slow4G63]

Put the boost gauge in. Put the boost gauge in. Put the boost gauge in.

Did you put it in yet?

I am with EclipseOwner95. I bet you are creeping now. Don't put the MBC in yet, since you have no idea what you are running now.

The amount of boost as everything to do with the exhaust. If the WG can't get rid of enough exhaust going through the turbine, the boost pressure will rise up (also known as creeping). This usually happens when you remove restrictions from the exhaust (sound familiar?) So, you now have the turbo sucking in a WHOLE lot more air that it used to. The ECU is fine with that as long as it measures less that X amount. Once it goes over X amount, it steps in and goes "whoa...hold on, this isn't right" and shuts off the injectors (fuel cut).

Does that make sense?

Please, put the gauge in. Then tell us what it reads.

sorry guys!!! Didn't mean to sound like an ass.... thanks for all of the reply's!! I will hook my boost gauge up tonight, take it for a run, and tell you all what it reads! thanks for explaining how it all works! I would ask what would happen it the boost is higher, but I won't rush things

THANKS A TON GUYS!

 

[Omega]

Thank you.

If the boost is higher? Well.. the turbo becomes inefficient and turns into a hairdryer.

More boost = more heat. High boost with the T25 gives you really high intake temps and leaves it screaming for mercy... which leads into an early retirement.

Someone can correct me, but I think 16 (useful) PSI is about all its' got in it. Upper RPM's don't count.

 

[oldman]

Oh.. don't WOT anymore until you do so.

 

[slow4G63]

what does WOT mean?

 

[oldman]

what does WOT mean?

Wide Open Throtle or flooring the gas pedal.