PDA

View Full Version : E38 - How to smooth out Idle/Low RPM - MAF only?



tunedportcj5
December 21st, 2011, 04:07 AM
Forgive me if I have missed this in another post or tutorial, i have been researching for the past few hours with no luck! ;-)

MAF tuning has been a dream with the E38 but smoothing out idle - and low rpm accell has been a bit more challenging. If I fail the MAF to SD, my idle/accell issues go away. MAF BEN's are +/- 2%.

Motor is a stock 4.8, LS3 MAF, LS2 intake, with LS6 cam. 80lb injectors could cause an issue I guess.

Can I run SD until a certain RPM or MAF frequency? I set my MAF fail LOW to 3000hz, it failed but would not re-enable above those frequency's and stuck with the VE values. I thought it is supposed to re-enable?

12425

Thanks,
David

swingtan
December 21st, 2011, 09:15 AM
A log of the issue would help. With the mods you have, I would expect the car to run like a stocker, especially with the auto. In most cases I've seen, low speed roughness is usually due to fueling, so I'd start there. The logs will tell the story though.

Simon

tunedportcj5
December 21st, 2011, 10:20 AM
Thanks Simon, what PIDs would you recommend me logging for idle fuel, spark, etc...?

swingtan
December 21st, 2011, 10:44 AM
RPM,
ETCTP,
MAP,
VSS,
SPARKADV,
IVLVTMP,
IAT,
AFRATIO_DMA,
APCYL_DMA,
MAFFREQ2
MAF,
WO2AFR1
HO2S11,
HO2S21,
SHRTFT1,
SHRTFT2.

That should do it for starters....