sputtering at higher rpms on KA-T

[koukiKA240]

Alright well im here again with another problem. This time it idls fine now but is running so rich it fouls the plugs in a matter of minutes. When easing on the throttle it will sputter at mid rpm.

Would this have something to do with my stock FPR? Stuck open? closed? I have MSD 50# injectors, walbro fuel pump, safc2, and a JWT ECU.

Any guidence would help.Thanks again~Sam

[klattr1]

too much fuel prolly. get a wideband on that thing and tune it!

[Structure240sx]

exactly. wideband and street tune is all you needed before

[fiznat]

Yeah definetly get that fuel fixed, but also keep in mind that most high-rpm only problems are ignition related...

[klattr1]

Yeah definetly get that fuel fixed, but also keep in mind that most high-rpm only problems are ignition related...

true, but he commented saying that it was happening in mid-rpms easing into the throttle.

[koukiKA240]

Today SGP tested the MAF and it was OK, they tested the FPR and said it was doin its job. It still idles great but cuts out at 3500rpms.

Help me better understand something. I know what tuning the fuel system does but how exactly does the wideband O2 system work? All i know is it better reads the O2 levels so fuel changes can be made?

Tomorrow i will call them and give them the idea of using a wideband to iron out the sputter.

does the sputter mean it has too much fuel or not enough, is the fuel change made with the widband or does the wideband only tell you what needs to be done and the actual change is made with the SAFC or whatever fuel computer you are using?Thanks again for being patient with me~Sam

[Structure240sx]

the wideband is a separate o2 sensor that goes into the exhuast piping. this runs to its own display that will tell u the exact air/fuel ratio. adjustments are made separately via your safc. hard to tell exactly what it is. with fouled plugs, from running too rich, that could be the problem.

[nissanfanatic]

Check out your coil. Mine was doing something similar but it would start breaking up at like 3-5psi. Then it gradually got worse to the poing that it would do it under any boost at all. Then about a week later, my car wouldn't start. Changed out the coil and the problem was fixed. Just a suggestion. Hope it helps. Good luck.

[klattr1]

quite possibly as well.i didnt have a code for a bad internal coil but my car was cutting out pretty bad and when i took it took Nissan and put it on CONSULT, they told me it was bad so i took it home, changed out the distributor and it worked fine after that.

sorry for the long run-on sentences. lol

[koukiKA240]

actually when we were trying to crank it for the first time we werent getting any spark. Lucky for me i had a fresh junnkyard coil lieing around so we slaped it non and then i had spark.

Thanks for explaining the wideband meter

And so Klatter you think it could be the distributor?~Sam

[klattr1]

its prolly that or just too much fuel making it cut out. it could be one or the other. since you have 50lb injectors on stock ecu and havent really tuned for them yet, it could be too rich in some spots (in half throttle or whatever).but it cant hurt to install another working distributor just to see if its the suspect.

[Structure240sx]

he sent the ecu to jwt to get retuned

[koukiKA240]

Okay so the riddle may be solved. Turns out when i wired the 300zx maf to my harness i did it incorrectly. The maf was sending a constant 12v signal to the ecu causing it to run rich and the hickup at 3500. No more hickup and idle is still good. Tomorrow it will make its way to the exhaust shop to have the wastegate blowoff routed to the exhaust.

Thanks for all your help Klatter and structure, you guys have helped so much.~Sam

[nissanfanatic]

Good to hear you got it fixed!