Engine or driveline vibration WOT in gears 4-6

rudypoochris · 06-16-2012, 07:25 PM

Hi Guys,

I am getting a rough sound and some vibration when I floor it in gears 4-6 between 2,000 and 4,000 rpms. In testing WOT didn't cause this from 1,300-2,000 and was not noticeable past 4,000rpm.

I experience this mostly when passing in 5th or 6th at 3,000rpm. My car isn't pulling timing and had no codes other than 2AAF. This sound/vibration is present on all tuned maps and can also be heard without the tune on (stock). The difference is that the sound and vibration is more intense on the more powerful maps and almost unnoticeable stock.

I am running an E85-91 mix and have noticed this with mixtures of 25% and 50%. I will test with just 91 to see if it happens as well...

I am thinking these are possible causes:

1. Transmission input bearing
2. Carbonization of the intake valves
3. Injector/HPFP issue
4. E85 causes the car to run rough in general (people have mentioned rough starts)
5. Something screwed with the motor internals

Thoughts? Thanks!

Here is a log when it is happening (Terry has already said this all looks good... just for reference here. 50-50 E85 mix so AFRs are high intentionally...):

3rd gear pull where it is not happening:

Beakmoney · 07-05-2013, 04:23 PM

Did anyone ever have this issue AND resolve it? My car was at the third dealer for a total of 2 weeks and they are scratching their heads after replacing a driveshaft support bearing.

Also my issue is not WOT, the higher the vehicle speed, the less throttle is required to make the vibration happen, also some days are worse than others.

06-16-2012, 07:25 PM	#1
rudypoochris Private 5 Rep 99 Posts Drives: 08 E92/72 Datsun 240z Join Date: Mar 2011 Location: Bay Area iTrader: (0)	Engine or driveline vibration WOT in gears 4-6 Hi Guys, I am getting a rough sound and some vibration when I floor it in gears 4-6 between 2,000 and 4,000 rpms. In testing WOT didn't cause this from 1,300-2,000 and was not noticeable past 4,000rpm. I experience this mostly when passing in 5th or 6th at 3,000rpm. My car isn't pulling timing and had no codes other than 2AAF. This sound/vibration is present on all tuned maps and can also be heard without the tune on (stock). The difference is that the sound and vibration is more intense on the more powerful maps and almost unnoticeable stock. I am running an E85-91 mix and have noticed this with mixtures of 25% and 50%. I will test with just 91 to see if it happens as well... I am thinking these are possible causes: 1. Transmission input bearing 2. Carbonization of the intake valves 3. Injector/HPFP issue 4. E85 causes the car to run rough in general (people have mentioned rough starts) 5. Something screwed with the motor internals Thoughts? Thanks! Here is a log when it is happening (Terry has already said this all looks good... just for reference here. 50-50 E85 mix so AFRs are high intentionally...): 3rd gear pull where it is not happening:
	Appreciate 0 Tweet Quote

07-05-2013, 04:23 PM	#2
Beakmoney Private 6 Rep 87 Posts Drives: Company car+07 335i Join Date: Aug 2012 Location: RI iTrader: (3)	Did anyone ever have this issue AND resolve it? My car was at the third dealer for a total of 2 weeks and they are scratching their heads after replacing a driveshaft support bearing. Also my issue is not WOT, the higher the vehicle speed, the less throttle is required to make the vibration happen, also some days are worse than others.
	Appreciate 0 Quote