Chasing my tail - Cylinder misfire codes different cylinders - Wiring or ECU?
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Chasing my tail - Cylinder misfire codes different cylinders - Wiring or ECU?
I'm about to lose my mid.
Issue:
- Got 2 Cylinder codes, both for cyl #1, coil problem and misfire. Car drove as if cylinder 1 wasn't firing (like crap). I replaced coil pack 1 with new, which fifty sources said was on the front of this 4 cyl turbo.
- The outside of the electrical connector disintegrated. Yay Mercedes plastic choice which doesn't last 5 years. (I ordered new connectors.) The inside of the connector was fine.
- Upon replacing the #1 coil pack, the car drove fine for one trip, then then felt like a cylinder was misfiring again. Cyl #1 again showed same 2 codes.
- Replaced the coil pack again with new. Car drove fine, but got a bad coil code for cyl #1 yet again.
So I....
- Swapped the original Mercedes coil from #2 to #1 and #1 (new) to cyl 2. And tightened the little pin clamps in the connector. I was thinking maybe this new coil was to blame, and I of course never got a code for cyl 2.
- Car drives fine, but now I consistently get a bad coil code on....cyl #3 ???? Again, I swapped #1 and #2, so looking for possible movement of the code but not to #3.
So are the cylinder positions 1, 2, 3, 4 from front to back? Does Mercedes show codes according to cyl position or firing order? Did they program this ECU wrong for the code scanner? It seems weird that the coil swap produced a possible expected position change, but I never touched #3.
Also, been getting some other weird codes lately following some under hood work. Also, my AC compressor turn on wire was open, necessitating running a bypass wire. I'm also suspecting maybe the big fatty underhood wiring connectors near the air cleaner on top of an ECU module didn't like being taken off and resecured. I noticed some type of what looked like clear fluid in them when I took them apart and hit them with air in case any radiator fluid had gotten into them. (There was a coolant leak which started this entire fiasco.)
- Are there issues with the electrical connectors in these cars getting loose?
- Do these connectors come with some type of contact oil in them, or no?
- Any known issues with codes jumping around for cyl misfires?
- Anyone have any suggestions?
Thanks.
Issue:
- Got 2 Cylinder codes, both for cyl #1, coil problem and misfire. Car drove as if cylinder 1 wasn't firing (like crap). I replaced coil pack 1 with new, which fifty sources said was on the front of this 4 cyl turbo.
- The outside of the electrical connector disintegrated. Yay Mercedes plastic choice which doesn't last 5 years. (I ordered new connectors.) The inside of the connector was fine.
- Upon replacing the #1 coil pack, the car drove fine for one trip, then then felt like a cylinder was misfiring again. Cyl #1 again showed same 2 codes.
- Replaced the coil pack again with new. Car drove fine, but got a bad coil code for cyl #1 yet again.
So I....
- Swapped the original Mercedes coil from #2 to #1 and #1 (new) to cyl 2. And tightened the little pin clamps in the connector. I was thinking maybe this new coil was to blame, and I of course never got a code for cyl 2.
- Car drives fine, but now I consistently get a bad coil code on....cyl #3 ???? Again, I swapped #1 and #2, so looking for possible movement of the code but not to #3.
So are the cylinder positions 1, 2, 3, 4 from front to back? Does Mercedes show codes according to cyl position or firing order? Did they program this ECU wrong for the code scanner? It seems weird that the coil swap produced a possible expected position change, but I never touched #3.
Also, been getting some other weird codes lately following some under hood work. Also, my AC compressor turn on wire was open, necessitating running a bypass wire. I'm also suspecting maybe the big fatty underhood wiring connectors near the air cleaner on top of an ECU module didn't like being taken off and resecured. I noticed some type of what looked like clear fluid in them when I took them apart and hit them with air in case any radiator fluid had gotten into them. (There was a coolant leak which started this entire fiasco.)
- Are there issues with the electrical connectors in these cars getting loose?
- Do these connectors come with some type of contact oil in them, or no?
- Any known issues with codes jumping around for cyl misfires?
- Anyone have any suggestions?
Thanks.
Out Of Control!!
Joined: Apr 2019
Posts: 11,924
Likes: 6,776
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
I'm about to lose my mid.
Issue:
- Got 2 Cylinder codes, both for cyl #1, coil problem and misfire. Car drove as if cylinder 1 wasn't firing (like crap). I replaced coil pack 1 with new, which fifty sources said was on the front of this 4 cyl turbo.
- The outside of the electrical connector disintegrated. Yay Mercedes plastic choice which doesn't last 5 years. (I ordered new connectors.) The inside of the connector was fine.
- Upon replacing the #1 coil pack, the car drove fine for one trip, then then felt like a cylinder was misfiring again. Cyl #1 again showed same 2 codes.
- Replaced the coil pack again with new. Car drove fine, but got a bad coil code for cyl #1 yet again.
So I....
- Swapped the original Mercedes coil from #2 to #1 and #1 (new) to cyl 2. And tightened the little pin clamps in the connector. I was thinking maybe this new coil was to blame, and I of course never got a code for cyl 2.
- Car drives fine, but now I consistently get a bad coil code on....cyl #3 ???? Again, I swapped #1 and #2, so looking for possible movement of the code but not to #3.
So are the cylinder positions 1, 2, 3, 4 from front to back? Does Mercedes show codes according to cyl position or firing order? Did they program this ECU wrong for the code scanner? It seems weird that the coil swap produced a possible expected position change, but I never touched #3.
Also, been getting some other weird codes lately following some under hood work. Also, my AC compressor turn on wire was open, necessitating running a bypass wire. I'm also suspecting maybe the big fatty underhood wiring connectors near the air cleaner on top of an ECU module didn't like being taken off and resecured. I noticed some type of what looked like clear fluid in them when I took them apart and hit them with air in case any radiator fluid had gotten into them. (There was a coolant leak which started this entire fiasco.)
- Are there issues with the electrical connectors in these cars getting loose?
- Do these connectors come with some type of contact oil in them, or no?
- Any known issues with codes jumping around for cyl misfires?
- Anyone have any suggestions?
Thanks.
Issue:
- Got 2 Cylinder codes, both for cyl #1, coil problem and misfire. Car drove as if cylinder 1 wasn't firing (like crap). I replaced coil pack 1 with new, which fifty sources said was on the front of this 4 cyl turbo.
- The outside of the electrical connector disintegrated. Yay Mercedes plastic choice which doesn't last 5 years. (I ordered new connectors.) The inside of the connector was fine.
- Upon replacing the #1 coil pack, the car drove fine for one trip, then then felt like a cylinder was misfiring again. Cyl #1 again showed same 2 codes.
- Replaced the coil pack again with new. Car drove fine, but got a bad coil code for cyl #1 yet again.
So I....
- Swapped the original Mercedes coil from #2 to #1 and #1 (new) to cyl 2. And tightened the little pin clamps in the connector. I was thinking maybe this new coil was to blame, and I of course never got a code for cyl 2.
- Car drives fine, but now I consistently get a bad coil code on....cyl #3 ???? Again, I swapped #1 and #2, so looking for possible movement of the code but not to #3.
So are the cylinder positions 1, 2, 3, 4 from front to back? Does Mercedes show codes according to cyl position or firing order? Did they program this ECU wrong for the code scanner? It seems weird that the coil swap produced a possible expected position change, but I never touched #3.
Also, been getting some other weird codes lately following some under hood work. Also, my AC compressor turn on wire was open, necessitating running a bypass wire. I'm also suspecting maybe the big fatty underhood wiring connectors near the air cleaner on top of an ECU module didn't like being taken off and resecured. I noticed some type of what looked like clear fluid in them when I took them apart and hit them with air in case any radiator fluid had gotten into them. (There was a coolant leak which started this entire fiasco.)
- Are there issues with the electrical connectors in these cars getting loose?
- Do these connectors come with some type of contact oil in them, or no?
- Any known issues with codes jumping around for cyl misfires?
- Anyone have any suggestions?
Thanks.
You tested moving coil+ plugs over to gave known good in faulted cyl. - It's important to know if misfire moved or stayed.
> NEED PERFECT IGNITION...
You can not affort to run with marginal ignition.
The German plastic crumbling witness extreme heat that cooks coils insulation.
I'd replace ALL identical new: coils + boots + plugs + connector.
Take this opportunity to test compressions and inspect bores if you will.
When dealing with misfiring consider the fuel trims: LTFT to be near 0% (+/- 5 Pts). Lean mixtures are common offenders.
Hope this help you solve this.
