Engine almost stalls on cold start

travismelo3 · 01-19-2024, 07:45 PM

Hi, so I recently installed catless Downpipes on my car, I don’t have a tune. Right after the installation it started fine, and on the 3rd or 4th cold start, it started, dropped way down in rpms, jumped back up in rpms, dropped way down again, and back up to where it usually sits rpm wise on cold start. It seems like a fueling issue, but if anything it would be running rich, not lean from the downpipes. Any ideas? Thanks

M3SQRD · 01-20-2024, 06:13 AM

Did you install an intake at the same time as the DPs? Car should run fine with DPs only (i.e., no tune required).

AlmondJayRoM3 · 01-20-2024, 07:40 AM

Going through your multiple posts, I would suggest you consolidate all your issues into one post and lay out everything you did and all the issues you ran into. Based on your codes from a previous post and this, it looks like you are running lean. Did you modify your intake piping? Did you fix the chargepipe bolt issue? Have you verified you don’t have any boost leaks, etc.

01-19-2024, 07:45 PM	#1
travismelo3 Private 13 Rep 64 Posts Drives: 2016 F83 M4 Join Date: Oct 2021 Location: Florida iTrader: (0)	Engine almost stalls on cold start Hi, so I recently installed catless Downpipes on my car, I don’t have a tune. Right after the installation it started fine, and on the 3rd or 4th cold start, it started, dropped way down in rpms, jumped back up in rpms, dropped way down again, and back up to where it usually sits rpm wise on cold start. It seems like a fueling issue, but if anything it would be running rich, not lean from the downpipes. Any ideas? Thanks __________________ Travis
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01-20-2024, 06:13 AM	#2
M3SQRD Major General 2335 Rep 5,796 Posts Drives: E92 M3,G20 330ix,F22 240iX,F82 Join Date: Jun 2009 Location: Mid-Atlantic iTrader: (11)	Did you install an intake at the same time as the DPs? Car should run fine with DPs only (i.e., no tune required).
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01-20-2024, 07:40 AM	#3
AlmondJayRoM3 Captain 475 Rep 628 Posts Drives: 2016 M3 Join Date: Oct 2017 Location: Pittsburgh, PA iTrader: (0)	Going through your multiple posts, I would suggest you consolidate all your issues into one post and lay out everything you did and all the issues you ran into. Based on your codes from a previous post and this, it looks like you are running lean. Did you modify your intake piping? Did you fix the chargepipe bolt issue? Have you verified you don’t have any boost leaks, etc.
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