FastUnicorn

Hello everyone! I have a 2007 that I recently installed a KraftWerks Supercharger kit onto. I have been chasing down a miss/stumble under power (WOT) and have come up dry.

Initially I felt it @ 7500 rpm...in the datalogs the RPM and speed would go down for a few lines.

Recently, it seemed to occur any time I was making decent power/building boost. 4500+ RPM.

This morning on the way to work, it was coughing and missing at moderate throttle openings even below 4k rpm.

The car has no codes, and there is nothing obvious in the datalogs. The fuel duty cycle does jump up ~5% and the AFR jumps from 12 to 13 on the line when it misses.


During the SC install I installed/replaced:
Fuel pump sock - OEM
Fuel filter - Beck/Arnley
Fuel pump - Walbro 255lph GSS342
Fuel Pressure Regulator - Science of Speed
Injectors - Grams 1000cc
Spark Plugs - 1 step colder NGK Iridiums gapped 0.025
Coils - Denso
Coil connectors - OEM
(Other stuff that isn't pertinent to the discussion)


At this point I am guessing that the pump is dying, and that it was either not genuine or just bad out of the box. It could also be the FPR. I don't really want to just throw parts at it. Thoughts?

outeiroj

how was it right after the tune? that gap might be a bit much depending on power levels. currently at .22 but at .25 i was breaking up. Which map sensor are you using?

FastUnicorn

After the most recent tune, it would miss a bit right at the top. Using a Skunk2 3 bar MAP.

HawkeyeGeoff

Check your spark plug gap again, it sounds like spark blowout to me.

AP1Chief

lean spikes is typically spark blow out... lower it another .03"

outeiroj

any reason your not using the 4bar grams map that came with the kit?

also like ap1 chief said its likely spark blowout. like i mentioned in my first post i would recommend regapping the plugs

FastUnicorn

My kit did not come with a MAP sensor.

FastUnicorn

Whelp, I figured it out. Despite 0.025 being the number in my notes, I gapped the plugs to 0.045 when I put them in. It was spark plug blow-out. Thank you all for the help, especially John Vega for taking a look at my tune and pointing out other bonehead mistakes, but eliminating it as the source of the issue. Thank you all for your time!