Codes 29d9 & 29cf

blau iii · 10-16-2016, 12:24 AM

Last weekend, I had driven across the state to my buddy's wedding. While driving home, I got on it coming around an onramp to the turnpike. As soon as I hit peak boost in 3rd, the SES light came on. I have my JB4 set to auto-clear so after a mile or so, the light went out. While the light was on, the car would run real rough if i put my foot into the gas at all.

I didn't have time this week to trouble shoot so I just put the JB4 in map 0 and didn't have any issues.

I pulled the codes last night - 29D9 and 29CF. misfire in cyl 3 and low gas due to low tank. I replaced the plugs about 2 months ago so I moved onto the coils. I swaped cyl3 for cyl1 and ran it hard tonight, no light at all.

Should I just replace all the coils or could this problem have worked itself out?

I'm at 73k miles and have not walnut blasted yet. My only other mod is a DCI. I've been having a cold start issue where my car feels like a diesel for about 2 minutes in the morning but quickly goes away. I haven't been able to test that again since swapping the coils.

WTH could this be? Any suggestions?

Thanks!

muncie21 · 10-16-2016, 05:19 AM

If you have extra time/money putting in new coils wouldn't hurt and doesn't take long. The cold start could be many things, most recommend starting with plugs/coils and go from there. Check plugs for fouling and gas smell while you're at it as it could be injector(s) also

blau iii · 10-16-2016, 12:54 PM

i checked the plugs, no issues. guess i'm getting new coils..

mustachetacos · 09-25-2021, 12:20 AM

Do you remember if the new coils worked? Ran into the same issue.

10-16-2016, 12:24 AM	#1
blau iii Lieutenant 128 Rep 451 Posts Drives: 2008 335i schwartz on scwartz Join Date: Jul 2015 Location: Pittsburgh iTrader: (0)	Codes 29d9 & 29cf - a real brain teaser Last weekend, I had driven across the state to my buddy's wedding. While driving home, I got on it coming around an onramp to the turnpike. As soon as I hit peak boost in 3rd, the SES light came on. I have my JB4 set to auto-clear so after a mile or so, the light went out. While the light was on, the car would run real rough if i put my foot into the gas at all. I didn't have time this week to trouble shoot so I just put the JB4 in map 0 and didn't have any issues. I pulled the codes last night - 29D9 and 29CF. misfire in cyl 3 and low gas due to low tank. I replaced the plugs about 2 months ago so I moved onto the coils. I swaped cyl3 for cyl1 and ran it hard tonight, no light at all. Should I just replace all the coils or could this problem have worked itself out? I'm at 73k miles and have not walnut blasted yet. My only other mod is a DCI. I've been having a cold start issue where my car feels like a diesel for about 2 minutes in the morning but quickly goes away. I haven't been able to test that again since swapping the coils. WTH could this be? Any suggestions? Thanks!
	Appreciate 0 Tweet Quote

10-16-2016, 05:19 AM	#2
muncie21 First Lieutenant 122 Rep 397 Posts Drives: 335ix Join Date: Sep 2015 Location: PA iTrader: (0)	If you have extra time/money putting in new coils wouldn't hurt and doesn't take long. The cold start could be many things, most recommend starting with plugs/coils and go from there. Check plugs for fouling and gas smell while you're at it as it could be injector(s) also
	Appreciate 0 Quote

10-16-2016, 12:54 PM	#3
blau iii Lieutenant 128 Rep 451 Posts Drives: 2008 335i schwartz on scwartz Join Date: Jul 2015 Location: Pittsburgh iTrader: (0)	i checked the plugs, no issues. guess i'm getting new coils..
	Appreciate 0 Quote

09-25-2021, 12:20 AM	#4
mustachetacos Registered 0 Rep 1 Posts Drives: 09 335i E90 Join Date: Sep 2021 Location: Santa Ana, CA iTrader: (0)	Do you remember if the new coils worked? Ran into the same issue.
	Appreciate 0 Quote