Fuel cut problem at hight boost

[dan222000]

Hello,I was wondering if anyone could help me out on this one. I have a 1996 nissan 240Sx with a S13 SR20DET Redtop motor. I have a GT2871R .64 trim turbo, 550CC injectors, Z32 MAFS, Warbo 255 fuel pump, and a rom-tuned ECU (REDSHIFT). Once I raise the boost to 16lbs. i'm getting a slight fuel cut. My RPMS still climb but with a slight fuel cut popping here and there. My Nissan guy said that he gets this with all OBDII swaps using S13 redtops. Is this true or is it something with the tune or fuel? Could it be that I need bigger injectors? Any feed back would be appreciated.

Thanks,

[karmakaze]

Hello,I was wondering if anyone could help me out on this one. I have a 1996 nissan 240Sx with a S13 SR20DET Redtop motor. I have a GT2871R .64 trim turbo, 550CC injectors, Z32 MAFS, Warbo 255 fuel pump, and a rom-tuned ECU (REDSHIFT). Once I raise the boost to 16lbs. i'm getting a slight fuel cut. My RPMS still climb but with a slight fuel cut popping here and there. My Nissan guy said that he gets this with all OBDII swaps using S13 redtops. Is this true or is it something with the tune or fuel? Could it be that I need bigger injectors? Any feed back would be appreciated.

Thanks,

there is no such thing as an OBDII sr20det from a silvia/180 at least. All of the JDM sr20s are OBDI.

also, are you sure its fuel cut? you could just be blowing your spark out. try gapping your spark plugs at .25 and see if that makes a difference.

[Hijacker]

I think he was talking about the car being ODBII, not the motor. Swapping into an ODBII car can be tricky, but typically the car runs or not. A hesitation or fuel cut like this is indicitave of a different problem. I'm in agreeance with Karma on this. Double check your spark and then start isolation problems that could be causing anything like a fuel cut.

Does it only happen when you hit high rpms under full boost? Does it happen only when you hit full boost but are not in the upper rev range? Or does it happen when you're on partial boost at high rpms?

[IanS]

What are your AFRs like?

[dan222000]

Looks like i'm running rich. I don't have a wide band so I don't know exactly but My Air to fuel gauge is running rich at full throttle. My problem only happens at high rpm's and high boost and only happens every so often not all the time. I talked to Redshift and they said to check my grounds and my fuel pump. So I will check that this weekend and also check my spark plug gap. Thanks

[IanS]

Fuel cut, and running rich dont usually go together, Im betting you have spark blowout.

[Slideways^Jordan]

im

Fuel cut, and running rich dont usually go together, Im betting you have spark blowout.

Im curious about that, what the symptoms when you have spark blow out.

[IanS]

im Im curious about that, what the symptoms when you have spark blow out.

Spark blowout is most often noticed as a random misfire or hesitation at higher RPM, only when higher boost pressures are reached. Blowout will occur if spark plug gap is too large, I run 12 psi and a .030 spark plug gap, for 16 psi I would recomend a gap of .025 - .028.

[Slideways^Jordan]

Spark blowout is most often noticed as a random misfire or hesitation at higher RPM, only when higher boost pressures are reached. Blowout will occur if spark plug gap is too large, I run 12 psi and a .030 spark plug gap, for 16 psi I would recomend a gap of .025 - .028.

ok thats good to know its a big relief for me cause its happned to me 2 times when i was running 12psi.

Thanks for telling me i apreciate it alot.

[sr20det_ute]

my sr is having the same problem as soon as it hits boost, how do you cande spark plug gaps?