2009 E550 4Matic random misfire
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2007 cls 550
2009 E550 4Matic random misfire
Soon *** I start my car in the morning my check engine light flashes so I will have to turn offf my car and the flashing check engine light will stop I get codes p0300 p0302 p0304 p0303 & sometimes p0301 that’s all the spark plugs on the right passenger side the left side is fine I did new Oem spark plugs and coil packs even switch coils to see if they was bad but no change wat so Ever my car is straight piped with a X pipe installed it wasn’t doing this at first I dnt knw wat it can be any answers to this
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From: Melbourne, Australia
2010 ML550 VIN WDC1641722A564750, 2010 B180
Any other codes in last few months? Id be checking for vacuum leaks. start with checking battery and alternator health and then vacuum leaks. My M273 did this once because I hadnt put the airbox on fully. When cold, spray some brake cleaner around manifold mating surface with head given they all happen on one side. Be careful not to start a fire. If revs increase then you know. Check for damage to headers as well. Did you keep the cats and sensors? Maÿbe exhaust on one side is restricted- H pipe causing too much back pressure?
Thread Starter
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Joined: Jan 2021
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2007 cls 550
Any other codes in last few months? Id be checking for vacuum leaks. start with checking battery and alternator health and then vacuum leaks. My M273 did this once because I hadnt put the airbox on fully. When cold, spray some brake cleaner around manifold mating surface with head given they all happen on one side. Be careful not to start a fire. If revs increase then you know. Check for damage to headers as well. Did you keep the cats and sensors? Maÿbe exhaust on one side is restricted- H pipe causing too much back pressure?
air box is on right car does not rev just misfire wen you first start it and no cat or sensors are on the car it drives good wants the car is warmed up but misfires when u first start it but only the passenger side no other codes but them come up
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From: Melbourne, Australia
2010 ML550 VIN WDC1641722A564750, 2010 B180
When were the cats and O2 sensors removed? At the same time as the H pipe or beforehand? If the cats went before and it was fine then its probably back pressure from the H pipe. If not, the ECU is looking for signals from the O2 sensors as its in closed loop whilst the cats are cold. When the cats warm up, the rpms drop. Since there's no 02 sensors the ECU is confused?
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2007 cls 550
When were the cats and O2 sensors removed? At the same time as the H pipe or beforehand? If the cats went before and it was fine then its probably back pressure from the H pipe. If not, the ECU is looking for signals from the O2 sensors as its in closed loop whilst the cats are cold. When the cats warm up, the rpms drop. Since there's no 02 sensors the ECU is confused?
yes I did eve everything at once cut the cats off and resonators and mufflers but everything was fine till bout a a couple months then it start doing that and I have a X pipe not H if I installed o2 sensors even tho I dnt have cats will it work or I shud get a tune for this
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From: Melbourne, Australia
2010 ML550 VIN WDC1641722A564750, 2010 B180
I'm sure they'll be views from others that will give you a more definitive opinion. Problem you have is because of the changes, you can't be certain that it's the O2 sensors or something else. I'd find a reputable tuner to advise you on the removal of the O2 sensors and cats.
I'm struggling to work out how the ECU ooperates things like fuel trim and the adjustments its meant to make without the O2 sensors. What does your scan tool tell you about fuel trims? Should be less than +/-8%. Has fuel economy changed?
I'm struggling to work out how the ECU ooperates things like fuel trim and the adjustments its meant to make without the O2 sensors. What does your scan tool tell you about fuel trims? Should be less than +/-8%. Has fuel economy changed?
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2007 cls 550
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MBWorld Fanatic!
Joined: Jun 2014
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From: Melbourne, Australia
2010 ML550 VIN WDC1641722A564750, 2010 B180
Was thinking about your problem again. In addition to what's already been raised, and since all your misfires come on 1 bank, its possible that your cam timing is out, but just on 1 side. Does it do it all the time, or just when cold?
Were there any other codes and I'm not referring to OBD codes but module by module scanning codes? Might be worth considering the camshaft and crank sensors of the problem is persistent.
Were there any other codes and I'm not referring to OBD codes but module by module scanning codes? Might be worth considering the camshaft and crank sensors of the problem is persistent.
Thread Starter
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Joined: Jan 2021
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2007 cls 550
Was thinking about your problem again. In addition to what's already been raised, and since all your misfires come on 1 bank, its possible that your cam timing is out, but just on 1 side. Does it do it all the time, or just when cold?
Were there any other codes and I'm not referring to OBD codes but module by module scanning codes? Might be worth considering the camshaft and crank sensors of the problem is persistent.
Were there any other codes and I'm not referring to OBD codes but module by module scanning codes? Might be worth considering the camshaft and crank sensors of the problem is persistent.
