Bouncing revs
 

Hi!
mine is suffering the following desease: when i switch to neutral and drop throttle after driving load (it doesnot concern to stationary iding throttle games) from say 4000 rpm level, revs dropping down to idle speed and then bounce up to 1400-1500 rpms and then slowly goes down to idle speed level.
I have HKS snorkel, K&N drop in, sound tube delete and some oil catch can, stage2UEL OTS modifyed tune (it behaves the same on several various OTS ROMs, i didnot try stock ROM yet but the last thing i would think in this case is software issue) and OFH header and catless front pipe.
I was thinking that my intake could be leaking somehow, double checked possible leaks but didnot find any.
If someone faced same problem or may advise where should i put my sting first to check the leaks (i already deleted oil catch can and even breathed into/from PCV, but it didnot cure me bouncing) :bonk:
And my OFT or Techstream health check both don't show any DTCs.

check for intake or exhaust leaks
look at you long term fuel trim it it high at low rpm ie over 10

is the k&n an oiled filter if so try cleaning maf sensor maybe oil on maf sensor.

This is the log
http://datazap.me/u/ondreiko/some-wo...log=0&data=1-5

Thank you for the suggestion, will try cleaning MAF sensor. I've seen it not so long ago and it didnot look dirty, but will do anyway. What liquid could i use safely for sensor - soap water or petrol or wynn's? Or some sprayed carb cleaner?
As for leaks - i tried to avoid em just by manual checking and tightening the connections of possible leaking points but failed to find any (intake, didnot actually check exhaust).

does mine LTFT look in gauge? Then they are not leaks?:iono:

ltft looks good unlikely their is leaks

then where to put my sting into? =))

yes can see prroblem here

http://datazap.me/u/ondreiko/some-wo...-917-4476-4480


Verry strange maybe flash stock tune just to eliminate that, wont harm engine but may throw cel coe p0420 due to catless header..

not sure what problem could be maybe check battery volts weird things can happen if battery is dying. also check earth connections in engine bay.

maybe uplug and replug connector on throttle body wth ca switched off.

thank you mate. thought about the battery, and charged it by some automatic charging unit and it seemed the procedure went the normal way. Also when i went to dealer, asked them about and they just cleaned the throttle body, what didnot help neither.

yep, and i added peak bounce line as i see it
http://datazap.me/u/ondreiko/some-wo...4476-4480-4489

Remember that with a snorkel the MAF will catch hell with air being rammed in the box and the throttle closed. example take a fan and blow it in the box while idling your motor will act all sorts of crazy sometimes it stalls the motor. The MAF voltage is fluctuating with the throttle closed and that seams strange to me.


This is when I call my tuner and say hey check this out and he explains its nothing and I feel stupid just sayin. Thank goodness for DT

High pal!
It sounds very true and prospective taking into consideration the fact that i got this bounce only after i disengage the clutch and drop throttle, i.e. only while moving. On the stationary vehicle i cannot reproduce this bounce. The only thing confuses me a bit: how the air is getting inside the bumper? There shouldn't be a direct flow as the duct is located under the front bumper, or do i miss something?
And the suggection: if i use stock filter with same snorkel/airbox, should the issue leave? And one sad thing about the airbox: its rear part has ben slightly deformed due to the jams crowling underhood heat. Now i solved the hood ventilation problem, but the airbox remained deformed - i beleive it shouldnot leak as i checked, but i may appeаr too optimistic as usually:bonk:

I have a AIRAID cold air intake with a greddy scoop and Bill at Delicious Tuning has created a tune that makes the car drive like stock no issues. Now if I shoot a fan at it it will do what you described. Call Bill or Zac at delicious tuning I feel its your tune good luck.
As far as air flow behind your bumper its there and it's powerful.

Thank you again mate. Will try to find if its tru by adding some restrictive materiak into airbox and stock filter. If something changes, then you are crystally right.:happyanim:

Here is fresh log of mine
http://datazap.me/u/ondreiko/fresh-w...9-10-14&solo=2 starting with wot pulls (and there are some thereafter)
i seem knocking. Or not? Log looks really strange cos MAF is jumping upto 14+ whilst the pull - should this issue be somehow concerned to overflowing do you think? Or is this the direct reason for knocking? And do i knock at all (flkc) taking into consideration advance multiplier 1?