2008 ML350 misfiring cyl 6 under load
Thread Starter
Junior Member
Joined: Feb 2013
Posts: 74
Likes: 19
From: San Francisco
2006 SL55 AMG, 2012 Land Rover LR4, 2009 C63 AMG
I have seafoamed the oil and fuel tank (1 quart in the tank, half a quart in the oil, then ran it for 5 miles. I will let it sit overnight and drain the oil and see if there is any difference. I am now thinking more and more that I have a burnt exhaust valve.
Last edited by spawnywhippet; May 7, 2017 at 02:44 AM.
Thread Starter
Junior Member
Joined: Feb 2013
Posts: 74
Likes: 19
From: San Francisco
2006 SL55 AMG, 2012 Land Rover LR4, 2009 C63 AMG
I checked again with the brake fluid on all injectors, there is the tiniest of fluctuation in revs only when I spray injector 6, but it drops, not increases. The car is running better after the seafoam treatment, it runs without the check engine light on as long as I keep the revs below 2000 rpm. If I go much over that, it flashes on then stays permanently lit. The car has now done about 20 miles since I added the treatment. Perhaps there is heavy carbon build up?
I will do a manual compression and cylinder leakdown test tomorrow.
I will do a manual compression and cylinder leakdown test tomorrow.
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Joined: Oct 2011
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From: Bronx, N.Y.
2002 ML 320 & 2006 ML500
You said brake fluid and hope you meant Brake Cleaner??????????????????
You have to determine if the Brake Cleaner traveled down to where the intake mates with the head. Seal off the mating area and re-spray.
When you swapped the injectors, did you use new O-rings?
You have to determine if the Brake Cleaner traveled down to where the intake mates with the head. Seal off the mating area and re-spray.
When you swapped the injectors, did you use new O-rings?
Last edited by Maj. Dundee; May 8, 2017 at 07:50 AM.
MBWorld Fanatic!
Joined: Oct 2011
Posts: 7,107
Likes: 765
From: Bronx, N.Y.
2002 ML 320 & 2006 ML500
Thread Starter
Junior Member
Joined: Feb 2013
Posts: 74
Likes: 19
From: San Francisco
2006 SL55 AMG, 2012 Land Rover LR4, 2009 C63 AMG
AAAGH, mistyped again! I meant to say brake cleaner both times. Over-tired and overstressed with this car. Am fixing it after work when everyone else is in bed, trying to type on my laptop in the workshop where I am also doing 10 other things.
To confirm, no brake fluid has been near the injectors, brake cleaner only.
To confirm, no brake fluid has been near the injectors, brake cleaner only.
MBWorld Fanatic!
Joined: Oct 2011
Posts: 7,107
Likes: 765
From: Bronx, N.Y.
2002 ML 320 & 2006 ML500
If there was a different response when you sprayed on #6 then there is some sort of leak. Try the spray on cylinders 1-3.
What is you model designation, 164.xxx?
What is you model designation, 164.xxx?
Last edited by Maj. Dundee; May 9, 2017 at 06:28 AM.
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Thread Starter
Junior Member
Joined: Feb 2013
Posts: 74
Likes: 19
From: San Francisco
2006 SL55 AMG, 2012 Land Rover LR4, 2009 C63 AMG
Updates on the remedy and the eventual solution.
I initially decided to replace the cylinder head, due to 2 different mechanics diagnosing (guessing) it was bad.
After receiving the ebay unit and taking it for refurb, the cylinder head company told me that it was not able to be rebuilt, so while I decided whether to order a brand new one, I decided to put another $75 of Seafoam through the injectors, inlet and crankcase. I also replaced the o rings on the injectors of that bank just to be safe. I drove the car with the Seafoam for 100 miles, and each trip it got better and better, allowing me to drive for further and harder before a CEL came on. It was pumping out some white smoke, but that cleared up. Then I drove another 100 miles with no CEL at all and I replaced the oil again. The 200 miles old oil came out very black with black specs in it.
One morning a few weeks later, I got another CEL and pulled a code for the crank sensor. I replaced the crank sensor and did a learn-in procedure and it has run perfectly ever since. No check engine lights, smooth, lots of power. I think the root cause of the issue was carbon build up on the valves was preventing proper seating of the valve.
I initially decided to replace the cylinder head, due to 2 different mechanics diagnosing (guessing) it was bad.
After receiving the ebay unit and taking it for refurb, the cylinder head company told me that it was not able to be rebuilt, so while I decided whether to order a brand new one, I decided to put another $75 of Seafoam through the injectors, inlet and crankcase. I also replaced the o rings on the injectors of that bank just to be safe. I drove the car with the Seafoam for 100 miles, and each trip it got better and better, allowing me to drive for further and harder before a CEL came on. It was pumping out some white smoke, but that cleared up. Then I drove another 100 miles with no CEL at all and I replaced the oil again. The 200 miles old oil came out very black with black specs in it.
One morning a few weeks later, I got another CEL and pulled a code for the crank sensor. I replaced the crank sensor and did a learn-in procedure and it has run perfectly ever since. No check engine lights, smooth, lots of power. I think the root cause of the issue was carbon build up on the valves was preventing proper seating of the valve.
Last edited by spawnywhippet; Jun 27, 2017 at 01:41 PM.
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