Fuel Cut?

[2skippy]

Heard a lot about it, now I suspect I have it but need someone to confirm. I noticed when I really get on it I will build boost pretty steadily, but once I hit about 10psi and 5k I get no more power increase, kinda like I hit a rev limit and the car kinda shudders then I shift and boom powers back. I have an Evo 8 pump and FIC 550's with a ebay 20g.

 

[1davho]

What are you tuning with? Are you running some sort of logger also? I'm sure it won't run right unless you have some sort of tune on it. My car would stop at 6000 rpm and o would shift and it would still be bogging down. After running at cruise speeds for a second it would pick back up. I knocked my cat out and now it runs better than it ever has. Could also be bad or incorrectly gapped spark plugs or bad wires

My bad, I didn't see that you were using a neo. If you had a wideband and a logger, it would tell you a lot more about what is going on...

 

[MNsleeper]

^----- agreed. Need to log a/f to be positive. sounds like fuel cut or bad plugs, or your plugs gaps are to wide.

 

[007jimmy]

10psi at 5k? Sounds like you got boost leaks.

 

[Firegst]

I am having fuel cut issues as well, I am going to start a thread later after I do a BLT..thats what I recommend to you as well...I agree that 10 psi at 5k sounds like a boost leak as well...

When you have a boost leak your turbo has to work harder to maintain or build boost, this requires more air flow. When this is happening your MAF thinks its getting to much air and pulls fuel.

With the above being said I would suggest you re-gap your plugs, and or replaced them, check for boost leaks then go from there.

FUEL cut is your friend really, saves your engine.

 

[And_44]

When you hit fuel cut it literally feels like you hit a brick wall. You'll know it for sure when it happens. I never understood what it would feel like until I hit it one time only.

But your problem sounds like a maintence issue and nothing more. Spark plugs, wires, boost leak, o2 sensor, knock?

 

[delta448]

Heard a lot about it, now I suspect I have it but need someone to confirm. I noticed when I really get on it I will build boost pretty steadily, but once I hit about 10psi and 5k I get no more power increase, kinda like I hit a rev limit and the car kinda shudders then I shift and boom powers back. I have an Evo 8 pump and FIC 550's with a ebay 20g.

Definitely not fuel cut.

That ebay 20G isn't a world beater, but there's definitely something wrong if you're not able to make more than 10psi at 5k. Check shaft play first since it's easy, then BLT.

 

[Firegst]

When you hit fuel cut it literally feels like you hit a brick wall. You'll know it for sure when it happens. I never understood what it would feel like until I hit it one time only.

But your problem sounds like a maintence issue and nothing more. Spark plugs, wires, boost leak, o2 sensor, knock?

^ when your studdering and or missing from possibly one of the above, does the car kinda studder/pop...not allowing the rpms to increase? Also if it were a 02 sensor or knock sensor wouldnt the ecu throw a code? Could timing cause this issue? Or maybe even coil packs?

 

[And_44]

If the popping noise is coming from the exhaust it usually means excess fuel going through the exhaust. If so you look at issues that would cause excess fuel.

Those being your o2 sensor being bad. Usually it only throws a CEL if the heater circuit is malfunctioning not the sensor it self. Mine the heater worked but the sensor wasn't reporting anything so my fuel trims where at 100% all the time so the ECU burned rich to prevent a lean condition and resulted in popping in the exhaust from the unburnt fuel.

Poorly gapped plugs or weak ignition system will result in an underpowered ignition system.

What I meant by knock was that your ECU is seeing knock at the higher boost and rpms and retarding your timing which by you "the driver" can be felt as a sock in the muffler feeling, lose of power, and a rich condition as the spark is happening closer or after the point of ignition.

Knock sensor may or may not through a CEL. It will if the circuit is bad, but if the circuit is intact but sensor bad you can check a logger and usually it will read 42 counts of knock on a bad sensor.

OF COURSE this is all my experience with a 1g. I see you have a 2g so if your o2 sensor is bad you may get 3 CEL for just the front sensor being bad those being Front, Catalytic Converter, and Rear o2 sensor. If your not getting those it's probally good.

Intake leak is a strong possibility. Poor spark.

Reread OP post. Do you have any fuel management? Putting a larger pump and larger injectors will make you pig rich.

 

[delta448]

Reread OP post. Do you have any fuel management? Putting a larger pump and larger injectors will make you pig rich.

Profile says AFC Neo.