Help Troubleshooting Misfire

mziggy16 · 04-29-2020, 04:16 PM

A few days ago I took the Z out for a mental health drive. Shortly after leaving my house the ride got rough, power was low and it threw an SES. I limped it home 1/8th a mile, turned it off then back on and the SES and rough idle were gone.

Fast forward a few days and I fired her up and gingerly drove around the block and then gradually extended my range to include highway driving and a total of about 45 minutes of trouble-free pleasure. As I was pulling in my driveway the SES and rough idle returned, so I parked it, shut it down then turned it back on and everything was okay.

The code reader tells me P0301 Cylinder 1 misfire. The google machine tells me it could be many things, but most likely the ignition coil.

I pulled the coil and plug today (images attached, sorry for the blurry one). The plug has about 3k miles on it.

My plan is to replace the cyl 1 coil.

Questions:

1. How can I tell if I have a Bosch or Delphi coil? I'd like to make sure they all match. Was OE in 2007 Bosch? I see three different options:
Delphi OE: 12138616153
Bosch OE: 0221504470
Bosch OEM: 12138616153 (same pn as Delphi)

2. With 133k miles, should I replace all 6 coils? Cyl 4 coil was replaced 50k miles ago and the rest are original.

3. Any other thoughts on troubleshooting?

JAS1169 · 04-30-2020, 11:28 AM

Exchange the coil from #1 with another cylinder. Clear the code & then do another test drive. If a new code po301 travels on the cylinder you exchange the coil with. Then you confirmed it as a bad coil.

It's recommended to do all of the coils. However, it's not the end of the world if you only replace the bad one.

Unless maker marked I wouldn't be able to determine the actual maker of a coil.

wdb · 04-30-2020, 04:32 PM

Could be the photo but it look like there's a heap of deposits on that spark plug. Are they all like that? You might want to scope the cylinder and have a look at the piston etc.

mziggy16 · 04-30-2020, 04:53 PM

Quote:

Originally Posted by wdb

Could be the photo but it look like there's a heap of deposits on that spark plug. Are they all like that? You might want to scope the cylinder and have a look at the piston etc.

Interesting observation. Attached is a pic from when I changed the plugs last summer. Notice the one with the most build up? At the time, I showed it to my Indy mechanic and he didn't seem concerned.

Scoping a cylinder is beyond my abilities. Any other thoughts based on the current evidence?

mziggy16 · 04-30-2020, 09:33 PM

Quote:

Originally Posted by JAS1169

Exchange the coil from #1 with another cylinder. Clear the code & then do another test drive. If a new code po301 travels on the cylinder you exchange the coil with. Then you confirmed it as a bad coil.

It's recommended to do all of the coils. However, it's not the end of the world if you only replace the bad one.

Unless maker marked I wouldn't be able to determine the actual maker of a coil.

Jackpot. Swapped Cyl 1 and 2 coils today and took her for a spin: Threw a P0302 code - Cyl 2 misfire.

6 new coils on the way.

JAS1169 · 05-01-2020, 06:15 PM

Yea, it's really a ez test, which is almost fool-proof.

*must have a scan tool to confirm error travel.

04-29-2020, 04:16 PM	#1
mziggy16 Private First Class 31 Rep 135 Posts Drives: '07 Z4MC, '01 911 C4 Cabriolet Join Date: Nov 2011 Location: St. Louis, MO iTrader: (1)	Help Troubleshooting Misfire A few days ago I took the Z out for a mental health drive. Shortly after leaving my house the ride got rough, power was low and it threw an SES. I limped it home 1/8th a mile, turned it off then back on and the SES and rough idle were gone. Fast forward a few days and I fired her up and gingerly drove around the block and then gradually extended my range to include highway driving and a total of about 45 minutes of trouble-free pleasure. As I was pulling in my driveway the SES and rough idle returned, so I parked it, shut it down then turned it back on and everything was okay. The code reader tells me P0301 Cylinder 1 misfire. The google machine tells me it could be many things, but most likely the ignition coil. I pulled the coil and plug today (images attached, sorry for the blurry one). The plug has about 3k miles on it. My plan is to replace the cyl 1 coil. Questions: 1. How can I tell if I have a Bosch or Delphi coil? I'd like to make sure they all match. Was OE in 2007 Bosch? I see three different options: Delphi OE: 12138616153 Bosch OE: 0221504470 Bosch OEM: 12138616153 (same pn as Delphi) 2. With 133k miles, should I replace all 6 coils? Cyl 4 coil was replaced 50k miles ago and the rest are original. 3. Any other thoughts on troubleshooting? Attached Images __________________ CURRENT: '07 Z4 M Coupe /// ‘01 911 C4 Cab SOLD: '06 330i / '07 335i / '07 X5 4.8 / '13 335i
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04-30-2020, 11:28 AM	#2
JAS1169 Private First Class 50 Rep 156 Posts Drives: BMW 2003 Z4 Join Date: Sep 2017 Location: Mechanicsburg, PA iTrader: (0)	Exchange the coil from #1 with another cylinder. Clear the code & then do another test drive. If a new code po301 travels on the cylinder you exchange the coil with. Then you confirmed it as a bad coil. It's recommended to do all of the coils. However, it's not the end of the world if you only replace the bad one. Unless maker marked I wouldn't be able to determine the actual maker of a coil.
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04-30-2020, 04:32 PM	#3
wdb dances with roads 4722 Rep 4,096 Posts Drives: '07 E86, '02 996, '95 Seven Join Date: Jul 2015 Location: the perimeter iTrader: (4)	Could be the photo but it look like there's a heap of deposits on that spark plug. Are they all like that? You might want to scope the cylinder and have a look at the piston etc.
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05-01-2020, 06:15 PM	#6
JAS1169 Private First Class 50 Rep 156 Posts Drives: BMW 2003 Z4 Join Date: Sep 2017 Location: Mechanicsburg, PA iTrader: (0)	Yea, it's really a ez test, which is almost fool-proof. *must have a scan tool to confirm error travel.
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