Won´t rev past 5500rpm

[a_sesshoumaru]

it´s been a while since i dont ask for help starting a thread, usually searching was enougth but this problem got out of my hands already, it´s been 4 months or so since i get some kind of rpm cut at 5500rpm, the AFR is going steady 11.8 and when it stops reving is still 11`s, my EGT´s dont go up 1400F, and it doesnt matter if i am boosting 7psi, 12psi or 17psi, it always does it at 5500rpm, my mods are in my signature for referance, i am running already map, any suggestions? Thanks

 

[suprahero]

No codes? What are your plugs gapped to and have you checked them recently? Does it stutter or does it quit revving completely?

 

[a_sesshoumaru]

No codes? What are your plugs gapped to and have you checked them recently? Does it stutter or does it quit revving completely?

it does stutter, only code i have is code 41 wich i have had for 2 years and never gave me that problem, i am replacing my spark plugs next week and the fuel filter to see if that helps.

 

[CajunKenny]

I'm with suprahero. Try gapping your plugs to .028.

 

[supradjza80]

well here is an easy way to know if it is the plugs. If it is only doing it at high load (WOT) than I would say it is liklely ignition breakup. If it holds you to 5500 rpm just free revving in neutral or at low throttle low load (but high rpm) then I would say it is not ignition related.

 

[gaboonviper85]

Code 41 explains alot! Turn your ac off...don't touch the gas pedal....clear codes then check codes again...if you get a 41 that sure as hell would not help the issue...

I know you've had the code for 2 years but small problems don't fix themselves...this may come as a shock but they generally get worse as time goes on (atleast here on planet earth)...

 

[a_sesshoumaru]

well here is an easy way to know if it is the plugs. If it is only doing it at high load (WOT) than I would say it is liklely ignition breakup. If it holds you to 5500 rpm just free revving in neutral or at low throttle low load (but high rpm) then I would say it is not ignition related.

In neutral i can rev it all the way to 6500rpm, the problem is only under load, now is getting worst and 3rd gear i can only rev it to 4000rpm.
Edit: i am using grade 8 spark plugs, what should i gap them at?

 

[CajunKenny]

I'm with suprahero. Try gapping your plugs to .028.

 

[yoterman87]

I came on today to try and figure this out to i thikn my car is doing the same thing. it will sometimes let me hit full boost but other times it will only let me hit 3 or 4 psi. i thought maybe since it has been pretty cold here that maybe the temperature cut off was kicking in cause my temp gauge is not getting to op temp. but sometimes it wont even let me rev past 3300rpm. please help! lol

 

[supradjza80]

Code 41 explains alot! Turn your ac off...don't touch the gas pedal....clear codes then check codes again...if you get a 41 that sure as hell would not help the issue...

I know you've had the code for 2 years but small problems don't fix themselves...this may come as a shock but they generally get worse as time goes on (atleast here on planet earth)...

that would be code 51 you are referring too.

 

[supradjza80]

I came on today to try and figure this out to i thikn my car is doing the same thing. it will sometimes let me hit full boost but other times it will only let me hit 3 or 4 psi. i thought maybe since it has been pretty cold here that maybe the temperature cut off was kicking in cause my temp gauge is not getting to op temp. but sometimes it wont even let me rev past 3300rpm. please help! lol

Check codes, could be Fuel cut or could be the spark plugs/ignition break up. If you don't have code 34 it is likely the latter. If you have code 34 you are either running a non stock turbo or have a huge boost leak.

Also fix whatever is causing your car to run cold, it is not the cause of this problem but it is not good to run the car cold.

 

[yoterman87]

i checked the codes and none are coming up. i am pretty sure it is an ignition cut cause it is not going lean. and if it was a boost leak i didnt think it would run ok one minute and not the next. i also tried switching from the ls400 afm to the stock one and it ran ok for a bit then started messing up again. i also tried a different ecu as well. it started after i installed my 550cc injectors and put my new turbo on it.

 

[cuel]

41 is a tps code. Yes, it will effect the way the car runs.

 

[a_sesshoumaru]

now i replaced spark plugs, spark plug wires and coils and the problem persist, i think i have ignition break up or spark blown out but what do i have to replace to have this solved? only thing i noticed is one day i put brand new ngk spark plugs and for 1 day the car reved pretty good, with no problem at all, 2 days later the problem got back; i replaced for brand new denso ones thinking that the ngk were fautly and still the same. It`s been a few months with this problem now and i am starting to loose patience. Help!!!!!!!!!!!

 

[IJ.]

One more time......

5200 is usually torque peak and where cylinder pressures are at their highest hence the spark blowout, IF you have enough Octane and some way to adjust the timing map around that point you can dial in some more advance and that might get you over the blowout and remove the stumble, failing that you can try smaller plug gaps or upgrade the ignition system for a bigger zap.

 

[a_sesshoumaru]

One more time......

Yes i know, sorry, i only thought i should put it in the right forum; my question is, why i didn`t have this problem in the past when i used to boost 23psi everyday? unfortunatly i have no way to adjust timing only fuel, i have my ngk grade 8 gapped at 0.022", is it ok?
Thanks for your help IJ, i will try to gap them closer on monday and post the result.

 

[Nick M]

that would be code 51 you are referring too.

51 is the idle switch, 41 is the TPS position. It matters.

For the O.P, nobody has seen your car but you, you have to find out yourself. How much fuel pressure do you have? How good does the spark look in air? Bright white with a blue tint, or kind of yellow? The coil pack would not be my first check, but it still should be looked at.

Won't go above 5500 and stumbles bad above 5500 are too completely different things.

 

[a_sesshoumaru]

51 is the idle switch, 41 is the TPS position. It matters.

For the O.P, nobody has seen your car but you, you have to find out yourself. How much fuel pressure do you have? How good does the spark look in air? Bright white with a blue tint, or kind of yellow? The coil pack would not be my first check, but it still should be looked at.

Won't go above 5500 and stumbles bad above 5500 are too completely different things.

it seems like it would hit a brick wall at 5500, it starts accelerating awesome but suddenly it stops, you can even feel you have hit something from the drivers seat, the a/f gets to 14.7 but EGT`s never go above 1100F, even if i leave the foot on the gas pedal it wont go above 5500rpm, it feels like if the engine suddenly turns off, i will try to gap my spark plugs closer on monday as IJ suggested. I know is not a lean condition cause i have a map ecu and i can add fuel as i want it, but i have tried to add lots of fuel and still the same.
And the spark looks blue, i have checked that already.

 

[IJ.]

Will it rev harder if you keep it out of boost in a lower gear?

 

[a_sesshoumaru]

i shot a video with my cel phone, sorry about the quality but i hope it helps to describe it, this is a second gear pull, it gets to 5500rpm and suddenly stops and decelerate by it self, egts starting to come down too. i never took my foot off the gas pedal.
[video=youtube;p3KwGDNDXGo]http://www.youtube.com/watch?v=p3KwGDNDXGo[/video]

this is a 3rd gear pull trying to keep out of boost, as soon it starts to build some boost it cuts at about 4500rpm and got to 4200rpm then it tried to accelerate again and so on and on.
[video=youtube;rcoGg5Vhq6E]http://www.youtube.com/watch?v=rcoGg5Vhq6E[/video]

edit: in neutral it revs pretty well to 6500rpm.