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

 

[Spooling99]

Hitting fuel cut is definatley bad. what are you running for psi? Anything to control fuel?

 

[SLOWKID]

I'm pretty much stock i got a 3inch full exhaust, air fiter, greddy bov,balance shaft kit thats it
thanks

 

[Spooling99]

Well then i'd get a MBC and boost gauge and turn the boost down. also, i hope your not venting.
-ADAM-

 

[SLOWKID]

It was venting when i first got it and it was stalling after high boost.But i got a tube on it now.

 

[oldman]

Boost leak test, number one cause of fuel cut. Boost gauge should always be your first mod, BOV and exhaust will change your boost characteristics therefore a monitoring device is a must.

 

[Justin99GST]

im not sure if this is fuel cut or not but at highway speed, which here is around 60mph, in 5th gear if i floor it the car feels like its "jerking" it didnt do this when i first bought it i thought maybe it was due inpart to the not so great 2g bov so i replaced it with on from hks, that didnt fix it. if im at a high rpm it runs just fine its just at a low rpm going wot that this happens. i tried to look around in the problem diagnosis before asking this but i couldnt find anything. i might have over looked it. if there is a thread on this subject and someone could post the link to it that would be helpful. at the moment i have the hks ssqv bov, walbro 255 pump(rewired) and a blitz dual sbc spec s (which i happen to regret buying) i havent increased the boost at all, the analog gauge reads right around 14 psi and the blitz reads .89-.93 bar. thanks in advance.

 

[DevilSperm]

I'm assuming you've done a boost leak test right? Thats what it sounds like to me.

 

[andymoraitis]

Justin,

First things first. Please take a moment to fully update your member profile with a list of complete mods. This will make it easier to help you in the future. The issue you're describing generally has to do with spark/fuel (stuttering under load), but there are a couple of things that stood out.

1. Is your HKS BOV recirculated back into the intake tube? If not it needs to be since the ECU is metering air that itsn't being returned to the intake. This will be most apparent when coming to a stop (wants to stall) or in between shifts (will run rich).

2. You have a 255 pump, but do you have an aftermarket fuel pressure regulator? The lack of an AFPR with a 255 will cause stock FPR overrun. Once again, this will be hideously rich, kill performance and also potentially wash gas past your rings (dilutes the oil). This can also cause a stuttering since the motor will be overloaded and fighting a heinously rich condition.

3. If the above things are in oder and you still have stuttering issues, replaces the plugs and wires. Use non-platium NGK's (BPR6ES for stock boost and BPR7ES for more than 15psi). Gap them to .028 and you should be good to go.

4. It would also be a great idea to perform a boost leak test (http://www.vfaq.com - look under the Intake section) and replace the fuel filter.

Let us know what you find,

Andy

 

[97EclipseGS-T]

Sounds like a boost leak. I had them when I pulled from a higher gear. Trust me... if it was fuel cut.... it would feel like hitting a brick wall. Like everyone said... check for boost leaks. Let us know how it goes

 

[coving21]

If you do a boost leak test and that doesn't fix the problem get new plugs and wires. The same thing happenend to me so I did a boost leak and everything was fine. I went down to AMS and they pulled out my spark plugs and started to laugh. The plugs were gaped wrong and they were some autozone double prong POS!!!! Also the wires were autozone and the caps seperated from the wires, I think they were bosche and very small in diameter. I purchased AMS christmas special taylor 8mm with NGK i heat range cooler plugs which not only fixed the problem but made a world of difference with smoothness all around.
Hope this helps and good luck!!!!!!!

 

[dsmgrimreaper]

sounds like it might be plugs and wires not everthing wrong with a dsm is going to be boost leak, and my friend just resently had the same problem and he had 2 bad wires

 

[Justin99GST]

sorry about the profile, i just updated it. i am about to go check my plugs and look over the wires to make sure theres no damage to them, but i will probably replace them anyway. even though i my boost is around 14psi, i will be getting alot of stuff including a new turbo soon, would i be able to put the 7es plugs in? should only be about a month or so before i have the money to get all my stuff and i dont really want to have to buy plugs twice. i also planned on getting a regulator this paycheck, any suggestions on which on to get and what to set it at????

 

[ericbev]

sorry about the profile, i just updated it. i am about to go check my plugs and look over the wires to make sure theres no damage to them, but i will probably replace them anyway. even though i my boost is around 14psi, i will be getting alot of stuff including a new turbo soon, would i be able to put the 7es plugs in? should only be about a month or so before i have the money to get all my stuff and i dont really want to have to buy plugs twice. i also planned on getting a regulator this paycheck, any suggestions on which on to get and what to set it at????

The BPR7ES will be fine till you get your new setup going. Plugs are only 10 bucks anways so no worries there.

Two of the more common AFPRs out there are the aeromotive kit and the Full Throttle.

http://www.dsmtuners.com/parts/product_info.php?cPath=3_144_93&products_id=786
http://www.dsmtuners.com/parts/product_info.php?cPath=3_144_93&products_id=1188

The Full Throttle is a "bolt on" which bolts directly to the fuel rail and doesnt require much more. The Aeromotvie doesnt bolt right up to the rail but the very reasonably priced kit supplies everything you need for correct operation.

Base fuel pressure on a 2G is 43.5 lbs.

 

[squeak104]

I just had the same problem with my eclipse. It would stutter hard and feel like wheel hop any time it was around 15 psi or so. I replaced the plugs and wires and solved the problem. Hope it helps.

 

[oldman]

Damn it, and I though I was gonna be able to do my usual BOOST LEAK TEST posts.

 

[Justin99GST]

thanks for the responses, i also forgot to answer the last question that andy asked me, my hks bov isnt recirculated and my idle hasnt changed at all, nor does the car stall. i guess its supposed to throw the car off if its not recirculated but it hasnt messed mine up at all.

 

[andymoraitis]

Justin,

While the HKS doesn't leak boost at idle and cause most of the surging/low idle problems that other vented BOV's cause, it will still run the car rich in between shifts. Buy a recirculation tube for it and do things properly as it will maintain performance and also help keep the turbo spooled between shifts.

Also, get an AFPR on or change the pump to a 190 (less expensive). The overrun is killing your performance.

Cheers,

Andy

 

[Justin99GST]

andy,
i didnt know about the running rich between shifts thing. i just might have to go pick one up, i was going to try to get a afpr today or tomorrow. if i can get one should i raise the pressure from the stock 43.5 psi as mentioned below or leave it alone??

 

[Justin99GST]

also, will recirculating the bov cut down on how loud that thing is???

 

[the_red_pooch]

Andy, changing from a 255 to a 190 won't benefit him much will it? Even with a 190 he will still need an AFPR because the 190 is still larger than stock, so it should still overrun the stock FPR... Correct me if I'm wrong...

Justin, as for your concerns about how loud your bov is... It will quiet things down a bit yes, if you really want your bov to be loud and continue to be vented open atmosphere then you could purchase a MAFT and install that after the bov, usually somewhere on the intake pipe and as close to the intake as possible. That would allow you to still be venting open atmosphere and the ECU then will not be accounting for air that is no longer in the intake...

Hope I helped, good luck!

 

[TEAMONEINC]

Justin, I had the same problem you are inquiring about. I replaced my plugs, got the Accel wires, and also purchased the HKS recirculation kit (you make your own, but I bought it for only 40 bucks at DSM parts.com). My car runs extremely well now and does not stutter whatsoever. You can still hear your Supersequential, but its not nearly as loud. Just be assured that its better for your ride unless you go the MAFT route.

Chad

 

[No_Skillz]

Damn it, and I though I was gonna be able to do my usual BOOST LEAK TEST posts.

And go on and on about soapy water. (Btw... use soapy water, it's easier to spot your leaks)

 

[jepherz]

Another thing you can do is spray carb cleaner around areas that you suspect may be leaking while the car is idling. If you notice that the car revs up a bit, you've just found a leak!

 

[Justin99GST]

well i went last night and picked up a set of ngk wires and the recirculation kit. problem fixed, i havent put the recirculation kit on yet cause i have to do a little modification to the pipe but the wires fixed it and she running like a champ. thanks for all the help.

 

[mac 108]

Ok before I modded the car, it ran fine. However now that I have added a Aeromotive AFPR, Walbro 255, 650cc injectors, SAFC-II, Evo III exhaust manifold/02 housing, Evo 3 GT 16g, full 3in exhaust with no cat, running at 15 PSI, the car bucks and stutters above 6000 RPMs just before it shifts (it is an automatic).

There is a huge loss in power as well.

I changed the plugs and checked the timing. I am also running slightly rich (FTH 81%) at WOT. Same thing happened when the FTH was 100%. Am I hitting fuel cut and whatever the problem is, how can I fix it?