Misfire/stumble at cold start

YoungBlood · 05-12-2016, 01:00 PM

I recently did plugs, and a coil, due to a misfire. Now, on cold starts, for the first minute or so while I let the car warm up, I can feel a misfire, or stumble. No code or anything. If I run a log at idle with MHD, would I be able to determine if it's a leaking injector(s)? Is this a symptom of a bad injector? I plan to pull the injectors and check soon, but if I can run a log to diagnose the bad one that would be sweet. What should I look for in an idle/cold start log? Fwiw, plugs looked fine, and just did an oil change and it seemed normal (no fuel smell)

bigdnno98 · 05-12-2016, 01:29 PM

It is definitely a sign of a leaky injector. Let the car sit overnight. In the morning before you start it, pull the spark plugs. See if any are wet or smell like gas. Should be a tell tale sign. You may be able to see visual signs of failing injectors by pulling them and looking at the tips but this is not always the case.

YoungBlood · 05-12-2016, 01:41 PM

That's what I figured.. Holy shit I've had this car for 2 months and had every issue in the book haha. Hpfp, WG rattle, vanos, coil, and now injectors. Sigh... I would've traded it right back in if it showed these issues earlier on. I'll try the plug test. Are there any other ways of diagnosing this?

bigdnno98 · 05-12-2016, 03:29 PM

Quote:

Originally Posted by YoungBlood

That's what I figured.. Holy shit I've had this car for 2 months and had every issue in the book haha. Hpfp, WG rattle, vanos, coil, and now injectors. Sigh... I would've traded it right back in if it showed these issues earlier on. I'll try the plug test. Are there any other ways of diagnosing this?

I'll never own a BMW out of warranty LOL. Not really on the injectors.

YoungBlood · 05-12-2016, 03:34 PM

Well, hpfp was warrantied, and plugs and coil were $150, and vanos I just cleaned out, so not bad as far as cost, but headache/ work, that's another story haha

bigdnno98 · 05-12-2016, 03:41 PM

Quote:

Originally Posted by YoungBlood

Well, hpfp was warrantied, and plugs and coil were $150, and vanos I just cleaned out, so not bad as far as cost, but headache/ work, that's another story haha

I've been drag racing Mitsubishis for years. I'd rather be replacing coils, plugs and injectors on an N54, than transmissions, axles and transfer cases on Mitsubishis LOL.

Drummin335i · 05-12-2016, 03:55 PM

Same issue started recently for me. In for results.

Would valve cover gasket cause the rough idle/stumble on cold start? I am about to replace my VCG this weekend due to leakage.

ritzzzzzwik · 05-12-2016, 03:58 PM

curious. how many miles?

YoungBlood · 05-17-2016, 04:25 PM

90k, however, I noticed it was just a small misfire at idle all the time, even warm start. Ran a thing on techron through it and its a bit better. Need to check my plugs for leaking injectors, and walnut blast.. 90k and no walnut blast, might be part of the issue, or my one coil of a different brand

05-12-2016, 01:00 PM	#1
YoungBlood LongDongSilver 282 Rep 706 Posts Drives: e90 335i Join Date: Mar 2016 Location: Utah iTrader: (2)	Misfire/stumble at cold start I recently did plugs, and a coil, due to a misfire. Now, on cold starts, for the first minute or so while I let the car warm up, I can feel a misfire, or stumble. No code or anything. If I run a log at idle with MHD, would I be able to determine if it's a leaking injector(s)? Is this a symptom of a bad injector? I plan to pull the injectors and check soon, but if I can run a log to diagnose the bad one that would be sweet. What should I look for in an idle/cold start log? Fwiw, plugs looked fine, and just did an oil change and it seemed normal (no fuel smell)
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05-12-2016, 01:29 PM	#2
bigdnno98 Real Car Enthusiast 290 Rep 2,088 Posts Drives: 340xi Join Date: Jul 2011 Location: Germany iTrader: (8)	It is definitely a sign of a leaky injector. Let the car sit overnight. In the morning before you start it, pull the spark plugs. See if any are wet or smell like gas. Should be a tell tale sign. You may be able to see visual signs of failing injectors by pulling them and looking at the tips but this is not always the case.
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05-12-2016, 01:41 PM	#3
YoungBlood LongDongSilver 282 Rep 706 Posts Drives: e90 335i Join Date: Mar 2016 Location: Utah iTrader: (2)	That's what I figured.. Holy shit I've had this car for 2 months and had every issue in the book haha. Hpfp, WG rattle, vanos, coil, and now injectors. Sigh... I would've traded it right back in if it showed these issues earlier on. I'll try the plug test. Are there any other ways of diagnosing this?
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05-12-2016, 03:34 PM	#5
YoungBlood LongDongSilver 282 Rep 706 Posts Drives: e90 335i Join Date: Mar 2016 Location: Utah iTrader: (2)	Well, hpfp was warrantied, and plugs and coil were $150, and vanos I just cleaned out, so not bad as far as cost, but headache/ work, that's another story haha
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05-12-2016, 03:55 PM	#7
Drummin335i New Member 2 Rep 13 Posts Drives: 2009 335i E90 Join Date: Jan 2016 Location: Mountains, CO iTrader: (0)	Same issue started recently for me. In for results. Would valve cover gasket cause the rough idle/stumble on cold start? I am about to replace my VCG this weekend due to leakage.
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05-12-2016, 03:58 PM	#8
ritzzzzzwik Captain 236 Rep 723 Posts Drives: SO M4 MT Join Date: Oct 2014 Location: NOVA iTrader: (0)	curious. how many miles? __________________ 2007 335i E92 MT \| MFactory LSD \| Diff Brace \| MHD/Wedge Tuned\| BL Coils \| Stg2 lpfp BoostConcepts \| VRSF DPs \| VRSF 7" HD FMIC \| DCI \| VRSF CP \| BMW SSK \| Billstein PSS Coilovers \| M3 Control Arms \| Whiteline Rear SF Inserts \| SS brake lines \| Z4 35is Rotors \| Hawk 5.0 pads \| M219s + PSS \| PE Mod -SOLD 2016 M4 F82 MT
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05-17-2016, 04:25 PM	#9
YoungBlood LongDongSilver 282 Rep 706 Posts Drives: e90 335i Join Date: Mar 2016 Location: Utah iTrader: (2)	90k, however, I noticed it was just a small misfire at idle all the time, even warm start. Ran a thing on techron through it and its a bit better. Need to check my plugs for leaking injectors, and walnut blast.. 90k and no walnut blast, might be part of the issue, or my one coil of a different brand
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