KA-T part throttle sputter/jerking VIDEO - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

coupe92 · 05-20-2012, 04:30 PM

hey guys...At part throttle, higher rpms (5000+) my KA-T will start jerking back and forth and the rpms jump up and down until I either let off or go WOT. The car is fine at WOT and lower rpm part throttle, I just can't figure out why I can't be part throttle at high RPMs. It's running an enthlapy ecu, 740s, n62 maf (12" from turbo) stock fpr (problem?) wally 255 and an ISIS t25/t28.

Anyone have a similar issue? Here's a video to help you understand.
Ka24det sputter problem.mp4 - YouTube

Any help is much appreciated.

AdamR · 05-21-2012, 10:43 AM

What is your AFR like during that?

coupe92 · 05-21-2012, 01:50 PM

Just checked, the AFR goes really rich, showing 10.0 on the wideband, where WOT is usually around 11.0. I know a boost leak can make you run rich but why at only part throttle does it have a problem? WOT is fine.

Also, my car runs the same with the o2 sensor plugged in or not. It has been this way ever since It was N/A, but I never threw a CEL so I didn't know if it made a difference. Could this be the problem?

05-20-2012, 04:30 PM	#1
coupe92 Leaky Injector Join Date: May 2011 Location: Louisville KY Posts: 120 Trader Rating: (3) Feedback Score: 3 reviews	KA-T part throttle sputter/jerking VIDEO hey guys...At part throttle, higher rpms (5000+) my KA-T will start jerking back and forth and the rpms jump up and down until I either let off or go WOT. The car is fine at WOT and lower rpm part throttle, I just can't figure out why I can't be part throttle at high RPMs. It's running an enthlapy ecu, 740s, n62 maf (12" from turbo) stock fpr (problem?) wally 255 and an ISIS t25/t28. Anyone have a similar issue? Here's a video to help you understand. Ka24det sputter problem.mp4 - YouTube Any help is much appreciated.

05-21-2012, 10:43 AM	#2
AdamR Leaky Injector Join Date: Jan 2008 Location: Owensboro, KY Age: 40 Posts: 134 Trader Rating: (0) Feedback Score: 0 reviews	What is your AFR like during that?

05-21-2012, 01:50 PM	#3
coupe92 Leaky Injector Join Date: May 2011 Location: Louisville KY Posts: 120 Trader Rating: (3) Feedback Score: 3 reviews	Just checked, the AFR goes really rich, showing 10.0 on the wideband, where WOT is usually around 11.0. I know a boost leak can make you run rich but why at only part throttle does it have a problem? WOT is fine. Also, my car runs the same with the o2 sensor plugged in or not. It has been this way ever since It was N/A, but I never threw a CEL so I didn't know if it made a difference. Could this be the problem?