Sudden misfires + eccentric shaft sensor codes, but NO oil in connector

jacco · 05-20-2018, 10:01 PM

This could very well be related to this thread:
http://www.e90post.com/forums/showthread.php?t=1494117
but I decided to start a parallel one just in case it's not.

I have a 2010 E91 328i with N52 engine, 62k miles. It's thrown a misfire code once or twice in the 22k miles we own it, which prompted me to replace plugs & coils about 1000 miles ago. It ran fine since, but fuel consumption has always been on the high side IMHO (~17 mpg in mostly city driving, RWD car).

This morning it suddenly started to idle poorly: It shakes, runs rough, and the CEL turned on. It showed a misfire on #3, and 2A31 + 2A47 eccentric shaft sensor codes.

I looked at the eccentric shaft sensor connector, there is NO oil in it. I also swapped the #2 and #3 coil. I cleared the codes and drove it about a mile. Symptoms are the same. Codes are currently:
29CF
2A31
2A32
2A47
29CE

For starters I have two questions:
- Are eccentric shaft sensors known to go bad without them leaking oil, and would that cause sudden symptoms like this?
- Could this be a "simple" coil/plug problem? I upgraded to the NGK LZFR6AP11GS plugs and Delphi coils, which are not what was on the car (Bosch coils and an older model NKG plug.)

Oh, I forgot to mention, there is a tiny bit of oil leak at the #4 plug, so it needs a new valve cover gasket anyway, presumably. Unlikely to be directly relevant, but throwing it out there anyway.

I also ran the car with the eccentric shaft sensor disconnected, this did not change a thing.

Any comments / suggestions much appreciated!

ColoradoCale · 05-20-2018, 10:25 PM

What are you using to pull codes?

If it's a coil problem try swapping coils with another cylinder (just pop the connector up, disconnect the harness and pull it.) If it's the coil the misfire will follow it to another cylinder. There won't be oil on the sensor connector, you'll have to disconnect it and see if there's oil in where the pins make contact (pretty obvious usually.) If the misfire doesn't follow the coil (try swapping #1 and #3 to see if it moves to #1) it's more likely to be the ESS. The ESS replacement isn't *too* bad if you're patient and have the tools, the rear 3 VC bolts are a tight space though. If you do that you can't reuse the aluminum screws/old VC gasket after they've been used/torqued. Pelican parts has a good how-to

jacco · 05-21-2018, 05:36 AM

Thanks for the response. I used INPA to pull the codes. (I'm an INPA newbie, so suggestions for other things to pull up there are appreciated.)

I tried swapping two coils, #2 and #3, but those now both threw a misfire code... I'm pretty sure that I properly reconnected them though. But good point, I should probably move those around again.

Cheers,
Jacco

jacco · 05-21-2018, 10:12 AM

Quote:

Originally Posted by ColoradoCale

There won't be oil on the sensor connector, you'll have to disconnect it and see if there's oil in where the pins make contact (pretty obvious usually.)

Sorry, I'd missed this part. I did pull the connector. It's completely dry and clean, not at all like the typical oily mess that seems to be the common failure people see with this eccentric shaft sensor. This is what prompted me to post here, I'm not sure how often these sensor fail in other ways? Is there any way to do some basic testing on these, with a volt meter for example?

ColoradoCale · 05-21-2018, 03:35 PM

Gotcha, if swapping coils again and making sure they’re fully connected doesn’t work, you might be able to find the sensor specs if you pull up the part number on realoem then poke through newtis

ColoradoCale · 05-21-2018, 07:44 PM

Was chasing similar issues in my threads here and here

jacco · 05-23-2018, 08:56 PM

Update: Last night I poked around the INPA sensor readings and could not find anything strange with the car running, other than the severe misfire that shook the car. It then turned out that that misfire had moved to the #2 cylinder. (A German would call that an Aha-Erlebnis I suppose...)

So an hour ago I took the car apart again and installed one of the old Bosch coils that were still sitting in a box on my work bench. Misfire solved immediately.

So I then did a chat with amazon (where I'd purchased the coils), they told me to bug Delphi instead (since it was more than 30 days after purchase). To speed things up I ordered one more coil (delivery Friday) and then wrote a lengthy email to Delphi, with 2 invoices and amazon chat transcript attached, to see if I can get my $28 back...

The question still remains why this coil suddenly failed after ~1k miles and 2 months of service?!? And why I had those eccentric shaft checksum errors is also still a mystery.

Al least I learned some INPA!

ColoradoCale · 05-25-2018, 03:06 PM

Nice!!! Could have just been one that wasn’t QCed correctly.

The checksum errors might have been from the misfires.

hassmaschine · 05-25-2018, 04:29 PM

Quote:

Originally Posted by jacco

Update: Last night I poked around the INPA sensor readings and could not find anything strange with the car running, other than the severe misfire that shook the car. It then turned out that that misfire had moved to the #2 cylinder. (A German would call that an Aha-Erlebnis I suppose...)

So an hour ago I took the car apart again and installed one of the old Bosch coils that were still sitting in a box on my work bench. Misfire solved immediately.

So I then did a chat with amazon (where I'd purchased the coils), they told me to bug Delphi instead (since it was more than 30 days after purchase). To speed things up I ordered one more coil (delivery Friday) and then wrote a lengthy email to Delphi, with 2 invoices and amazon chat transcript attached, to see if I can get my $28 back...

The question still remains why this coil suddenly failed after ~1k miles and 2 months of service?!? And why I had those eccentric shaft checksum errors is also still a mystery.

Al least I learned some INPA!

I guess this is another +1 to on replacing only bad coils... and not throwing out the baby with the bathwater.

Glad you got it resolved!

jacco · 05-29-2018, 07:50 AM

Quote:

Originally Posted by hassmaschine

Glad you got it resolved!

Thanks guys. So am I... I installed the new Delphi coil on Saturday, all back to normal.

simplesilver · 06-19-2018, 03:22 PM

i'm happy it worked out for you in the end...!

05-20-2018, 10:01 PM	#1
jacco New Member 1 Rep 7 Posts Drives: E39 540i/6 + E91 328i Join Date: Mar 2013 Location: Garrett Park, MD, USA iTrader: (0)	Sudden misfires + eccentric shaft sensor codes, but NO oil in connector This could very well be related to this thread: http://www.e90post.com/forums/showthread.php?t=1494117 but I decided to start a parallel one just in case it's not. I have a 2010 E91 328i with N52 engine, 62k miles. It's thrown a misfire code once or twice in the 22k miles we own it, which prompted me to replace plugs & coils about 1000 miles ago. It ran fine since, but fuel consumption has always been on the high side IMHO (~17 mpg in mostly city driving, RWD car). This morning it suddenly started to idle poorly: It shakes, runs rough, and the CEL turned on. It showed a misfire on #3, and 2A31 + 2A47 eccentric shaft sensor codes. I looked at the eccentric shaft sensor connector, there is NO oil in it. I also swapped the #2 and #3 coil. I cleared the codes and drove it about a mile. Symptoms are the same. Codes are currently: 29CF 2A31 2A32 2A47 29CE For starters I have two questions: - Are eccentric shaft sensors known to go bad without them leaking oil, and would that cause sudden symptoms like this? - Could this be a "simple" coil/plug problem? I upgraded to the NGK LZFR6AP11GS plugs and Delphi coils, which are not what was on the car (Bosch coils and an older model NKG plug.) Oh, I forgot to mention, there is a tiny bit of oil leak at the #4 plug, so it needs a new valve cover gasket anyway, presumably. Unlikely to be directly relevant, but throwing it out there anyway. I also ran the car with the eccentric shaft sensor disconnected, this did not change a thing. Any comments / suggestions much appreciated!
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05-21-2018, 03:35 PM	#5
ColoradoCale Enlisted Member 4 Rep 33 Posts Drives: F10 528i xDrive; Z32 300ZX TT Join Date: Oct 2017 Location: Colorado iTrader: (0)	Gotcha, if swapping coils again and making sure they’re fully connected doesn’t work, you might be able to find the sensor specs if you pull up the part number on realoem then poke through newtis
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05-21-2018, 07:44 PM	#6
ColoradoCale Enlisted Member 4 Rep 33 Posts Drives: F10 528i xDrive; Z32 300ZX TT Join Date: Oct 2017 Location: Colorado iTrader: (0)	Was chasing similar issues in my threads here and here __________________ Incomplete list of old and current cars: 1972 Datsun 240Z; 1992 Jeep Cherokee XJ w/ 8" lift; 1992 BMW 325is; 1991 ground up drift built Nissan 240SX convertible; 2004 F250 6.0 w/ 4" lift; 1991 300ZX TT: Greddy everything; 2006 BMW 325xi; 2012 BMW 528xi
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05-23-2018, 08:56 PM	#7
jacco New Member 1 Rep 7 Posts Drives: E39 540i/6 + E91 328i Join Date: Mar 2013 Location: Garrett Park, MD, USA iTrader: (0)	Update: Last night I poked around the INPA sensor readings and could not find anything strange with the car running, other than the severe misfire that shook the car. It then turned out that that misfire had moved to the #2 cylinder. (A German would call that an Aha-Erlebnis I suppose...) So an hour ago I took the car apart again and installed one of the old Bosch coils that were still sitting in a box on my work bench. Misfire solved immediately. So I then did a chat with amazon (where I'd purchased the coils), they told me to bug Delphi instead (since it was more than 30 days after purchase). To speed things up I ordered one more coil (delivery Friday) and then wrote a lengthy email to Delphi, with 2 invoices and amazon chat transcript attached, to see if I can get my $28 back... The question still remains why this coil suddenly failed after ~1k miles and 2 months of service?!? And why I had those eccentric shaft checksum errors is also still a mystery. Al least I learned some INPA!
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05-25-2018, 03:06 PM	#8
ColoradoCale Enlisted Member 4 Rep 33 Posts Drives: F10 528i xDrive; Z32 300ZX TT Join Date: Oct 2017 Location: Colorado iTrader: (0)	Nice!!! Could have just been one that wasn’t QCed correctly. The checksum errors might have been from the misfires.
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05-20-2018, 10:25 PM	#2
ColoradoCale Enlisted Member 4 Rep 33 Posts Drives: F10 528i xDrive; Z32 300ZX TT Join Date: Oct 2017 Location: Colorado iTrader: (0)	What are you using to pull codes? If it's a coil problem try swapping coils with another cylinder (just pop the connector up, disconnect the harness and pull it.) If it's the coil the misfire will follow it to another cylinder. There won't be oil on the sensor connector, you'll have to disconnect it and see if there's oil in where the pins make contact (pretty obvious usually.) If the misfire doesn't follow the coil (try swapping #1 and #3 to see if it moves to #1) it's more likely to be the ESS. The ESS replacement isn't too bad if you're patient and have the tools, the rear 3 VC bolts are a tight space though. If you do that you can't reuse the aluminum screws/old VC gasket after they've been used/torqued. Pelican parts has a good how-to
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05-21-2018, 05:36 AM	#3
jacco New Member 1 Rep 7 Posts Drives: E39 540i/6 + E91 328i Join Date: Mar 2013 Location: Garrett Park, MD, USA iTrader: (0)	Thanks for the response. I used INPA to pull the codes. (I'm an INPA newbie, so suggestions for other things to pull up there are appreciated.) I tried swapping two coils, #2 and #3, but those now both threw a misfire code... I'm pretty sure that I properly reconnected them though. But good point, I should probably move those around again. Cheers, Jacco
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06-19-2018, 03:22 PM	#11
simplesilver New Member 6 Rep 26 Posts Drives: 07 328i sedan automatic Join Date: May 2017 Location: Ontario Canada iTrader: (0)	i'm happy it worked out for you in the end...!
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