Part Throttle Stutter

Post by **WDRacing** » Wed Jul 27, 2005 6:13 am

Anyone running the SAFCII with a 300ZX MAF have problems with the part throttle cruise. If I try to maintain a speed without accelerating the motor stutters pretty bad. Runs like a raped ape with the throttle stabbed though.

My settings are ALL CORRECT and the AFR is tuned via wideband for 14.5 off boost and 11.7 on boost. So it's not a matter of tuning.

Any suggestions for me to check?

WD

Post by **NateDogg** » Wed Jul 27, 2005 6:17 am

What does the timing show when this occurs and at what load/rpm/tp?

Post by **WDRacing** » Wed Jul 27, 2005 6:20 am

RPM varies a tad, usually 2400-2800. It is almost always with 17-21% throttle though. And only when that position is maintained.

Timing is only controlled via the stock ecu while off boost. I have the BTM to retard timing on boost.

Post by **NateDogg** » Wed Jul 27, 2005 6:32 am

Maybe S-AFC is throwing off the timing. How do your plugs look? Maybe 14.5 is a little lean?

Post by **Craving4Boost** » Wed Jul 27, 2005 8:53 am

WD, how partial are you talking about? with a piggy back it does not like partial throttle and you can get weird things happening...but how bad is it? it could probably just be the fact you have a piggy back

Post by **virus77** » Wed Jul 27, 2005 9:05 am

whats your A/F when the sputtering is happening?

Post by **toki** » Wed Jul 27, 2005 9:06 am

where are you hi/lo crossover points? im going to guess you are dipping in to a map that is too rich.

Post by **WDRacing** » Wed Jul 27, 2005 11:16 am

AF is 14.7 - 15, the throttle positions aren't close to my hi/lo points. I'm in turbo lag until 4200rpm so mine are set to 35-60. I'm going to hook up my multi meter and check my TPS voltage today. I may have bumped it during the down time.

WD

Post by **klattr1** » Wed Jul 27, 2005 12:18 pm

is the bov opening/closing during that stu stu stu studder?

whats your vacuum at when it does it as well?

Post by **nissanfanatic** » Wed Jul 27, 2005 1:53 pm

I noticed the exact same thing with my stock ECU w/FMU and BTM setup. I would stutter really bad going right into third gear. After doing the Enthalpy setup, I noticed it went away. But I remember Ivan saying something about Phils car doing a similar act adn it was the TPS. Not that it wasn't set right, but that it was just bad.

Post by **WDRacing** » Wed Jul 27, 2005 4:19 pm

Car just crapped a starter. More info to come in 8-9 friggin days.

Part Throttle Stutter

Part Throttle Stutter

Re: (WDRacing)

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