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misfires and catch can full of fuel - o2's or injector?
I was wot around 5500rpm and the cel started flashing. The car was shaking so I backed off the throttle completely and it wouldn't accelerate even with the lightest of throttle so I coasted to a stop and turned the car off. Checked the codes and had a bunch of misfires and p2198 "o2 sensor stuck rich bank 2 sensor 1". Turned the car back on after a few minutes and there was no cel and the car idled fine. Idled for a while, drove slow and easy for a bit then continued to drive to work with no issues or any further codes.
Car was off for 7 hours so I cleared the preexisting codes and started her up. The exhaust was crackling much much more then usual like there was lots of extra fuel being burnt off. I'm running a full tank of e85 right now. Checked the codes and had 3 more pending misfires but she idled fine and drove fine. No illuminated cel and no more codes during the drive home.
When I got home (appx 60 miles since the first misfire earlier in the day) I checked the catch can and it was about 3/4's full of fuel and some milky oil. Last time I emptied the can was 3 weeks ago after an oil change and since that time I have driven 1700 miles. I would typically empty the catch can every 5 or 6 weeks (2000-2500 miles) and it would usually be 1/2 full. However, the mixture would be much thicker with milky oil and this time it was almost pure fuel/water with a small amount of oil.
First I was thinking bad o2 sensors until I saw the 3/4 full catch can. Now I'm thinking an injector is stuck open which maybe explains the p2198 code. I'm running the bosch 550 injectors that came with the EC flex fuel kit. Thoughts?
I have brand new o2 sensors in the garage that I bought months so I will be installing those just for good measure. I still have the oem injectors if I need to swap back and while I have the 550 injectors checked out if needed
I have the same persistent code after 1.5k miles on new OE injectors and O2 sensors. The sensor is warrantied so I bought the replacement already but haven't gotten around to getting it installed. The car runs fine though and feels strong, totally normal in daily operation so we'll see what happens upon replacement. I move on to the injectors if the problem is not solved.
Please pull spark plugs from #7 and #8, or if you have time, remove the valve cover from bank #2. That milky oil and the localised misfires makes me worry for your headbolts. I hope I'm wrong.
Check your oil. Is it over full, color, smell? Check your rail pressure with the engine off ignition on and see if it is bleeding down. If the injector was stuck open from what iv seen most people can’t restart the car after it’s been off a while cause it hydrolocked the cylinder. Replace the primary o2 sensor if all looks good. Iv had the random misfire thing happen twice to me with catless headers. It was the primary o2 each time.
Last edited by AMGonFire; Jan 5, 2019 at 10:55 AM.
I have the same persistent code after 1.5k miles on new OE injectors and O2 sensors. The sensor is warrantied so I bought the replacement already but haven't gotten around to getting it installed. The car runs fine though and feels strong, totally normal in daily operation so we'll see what happens upon replacement. I move on to the injectors if the problem is not solved.
Swapping 02's today and go from there
Originally Posted by Celicasaur
Please pull spark plugs from #7 and #8, or if you have time, remove the valve cover from bank #2. That milky oil and the localised misfires makes me worry for your headbolts. I hope I'm wrong.
Ive seen the milky substance the past few times I dumped the catch can since it has been cold and the car was running fine (no problems/codes). I believe it is condensation but there is still a strong fuel smell in the can.
Originally Posted by AMGonFire
Check your oil. Is it over full, color, smell? Check your rail pressure with the engine off ignition on and see if it is bleeding down. If the injector was stuck open from what iv seen most people can’t restart the car after it’s been off a while cause it hydrolocked the cylinder. Replace the primary o2 sensor if all looks good. Iv had the random misfire thing happen twice to me with catless headers. It was the primary o2 each time.
The oil might be a tad overfilled. Meaning, the oil line goes over the red section on the dipstick by a few millimeters. Still has that light brown color like it came out the bottle. I do smell fuel very slightly on the dipstick and also when I open the oil fill cap.
I have another blackstone container waiting for my next oil change. Maybe Ill put the mityvac down the tube and take a sample and send it out.
Swapping 02's today and go from thereIve seen the milky substance the past few times I dumped the catch can since it has been cold and the car was running fine (no problems/codes). I believe it is condensation but there is still a strong fuel smell in the can.
Ahhh fair play, phew. It's just that I've seen an M156 in the UK with a localised misfire in #4. When we pulled the valve cover to check, there was milky oil only around the #4 area on the inside of the valve cover and the cam lobes for #3 and #4 were glazed with rust. Hopefully your issue isn't as bad as that.
swapped o2s and cleared all previous codes. started her up and checked the torque pro app. had a 5, 7, 8 misfire pending only. pulled a few plugs and this is what they look like. all gapped at .40. Honestly IDK what these plugs are "supposed" to look like at 44000 miles. Im going to get new plugs anyway.
Wouldn't it be really nice if a set of fresh plugs cures the issue?
They look a little tired and look like they've been run a little on the lean side, with some small oil deposits over time. Either way, it's a good time to replace them. Fingers crossed for you.
2008 MB C350 4MATIC/2011 CL63 AMG/2014 C63 Coupe 507
I'm having the same friggin issue every year, catless with tune. However my CEL shows up and stays on for several weeks. When i punch the throttle for a good 5 to 10 seconds, and let go, it pops few times and then misfires and then im screwed. shes sitting in the garage..waiting to buy parts. happened 2x in one year..fml. Has fresh spark plugs and few new coils on the 507 coupe.
I'm having the same friggin issue every year, catless with tune. However my CEL shows up and stays on for several weeks. When i punch the throttle for a good 5 to 10 seconds, and let go, it pops few times and then misfires and then im screwed. shes sitting in the garage..waiting to buy parts. happened 2x in one year..fml. Has fresh spark plugs and few new coils on the 507 coupe.
2008 MB C350 4MATIC/2011 CL63 AMG/2014 C63 Coupe 507
Originally Posted by AMGonFire
what are the codes. Did you try the primary o2s
Last few times it was the 02 sensors, then last year it was 2 coils and sparks; this year its showing Ignition F and H, with random misfires and Cyl 2 and 6 misfire (which doesnt seem to make sense with the F and H codes)
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