View Single Post
      07-27-2021, 08:03 AM   #19
hellokitty
Brigadier General
hellokitty's Avatar
United_States
2896
Rep
3,726
Posts

Drives: '17 M3 ZCP DCT
Join Date: Jul 2010
Location: Southern California

iTrader: (2)

Quote:
Originally Posted by F82spaceship View Post
Quote:
Originally Posted by hellokitty View Post
Quote:
Originally Posted by TopJimmy View Post
Going back to stock intakes should always be an early or first step in diagnosing rough idle.
I had rough idle when going to flex fuel. This is what I had to do (it took me darn weeks of troubleshooting):

- Removed aftermarket intakes
- Installed OEM intake with paper filter
- Clean MAF sensor
- Swapped new maf sensor
- Fixed some wiring issues on flex fuel related to the ethanol sensor
- Changed to flex fuel plugs and adjusted gap to .020 per Cary Jordan
- Disabled cold start
- Disabled start up roar

When I disabled start up roar, my idling issue went away. Seems like start up roar gets confused with ethanol mixes and caused my choppy idle.
Interestingly enough, I had rough idle on cold start, and it was alleviated by removing the start up roar as well. My car is stock, with bm3 stage 1.
Do you have aftermarket intakes? If so, which ones?
__________________
2017 F80 M3 ZCP / AA GESI DPs / Akrapovic Evo / BBS FI-R 19" / Bend Calibration ECUTEK Flex Fuel | Bilstein B16 DDC + CS EDC / BMC Filters / BMS OCC / CSF HE / ESS CP / Nitto NT555R2 / PD Crank Hub / SPL Suspension / Uniden R7 / Wagner Top Mount IC

2021 Mini GP3 / BMC Filters / BM3 / Cary Jordan E30 / Wagner IC / Remus Race
Appreciate 0