Engine Jerky at 5500rpm on SR20Det Red Top.

[ngcharleshk]

Hi,

I have a REdtop SR20Det on my S13, when I go driving in the hills I always get a feeling of a fuel cut at high speed corners especailly when I had to hold the throttle half way down in the middle of the turn. I later realized that "fuel cut" feeling only happens on 5500rpm and it happens at every gear. It goes back to normal when the engine goes pass that point, for example at 5600+ the car just runs normal again. I have an Air/Fuel wideband gauge and it normal reads around 11.0 on boost, however, when the engine hits 5500rpm and I tried to hold the rev right there, the wideband reads 10.0, which is running a lot richer than compared to 11.0 , and when I rev it up more it goes back to around 11.0 A/F ratio. Does anyone have similar problem, can anyone tell me what can the problem be? Can it be a bad MAF sensor? Why does it even feel like a "fuel cut"when its running rich? Is it really bad for the engine if I still drive it hard on the track?

Any help would be highly apprecaited.

Thanks X 10000
Modified by ngcharleshk at 1:39 AM 8/28/2006

[IanS]

well 11 to 1 a/f is not stock, what else do you have done to the motor

[ILikeMy240sx]

Maybe your sparks are blowing out..

What kind of turbo + boost and what kind of plugs are you running?

Also, timing and boost/vac leak is something you might want to look into

[ngcharleshk]

I m running on stock boost and timing should not be the problem since the car is perfectly stable at idling. I just cahnged the spark plugs 1000 miles ago, so it shouldnt be the problem. I have Z32 fuel pump and fuel rail on my S13, otherthan that, its just a stock SR20Det running on stock boost. Hope the info i provide will help you guys to find out the problem. Thanks