Misfire at idle/low revs - ??? 1991 190E 2.3
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2007 ML 350 - VIN 4JGBB86E17A211020
Misfire at idle/low revs - ??? 1991 190E 2.3
Hi all...over the past few weeks (since that hideous streak of ultra cold weather here in the US) I have picked up a burble/mis-fire at idle and low revs (below 1000 rpm).
Had my tech change out the distributor/rotor and I changed the plugs. Also jiggled the plug wires (which are old) but that didn't change things.
Was wondering if it might be the plug wires or something else I missed...like the plug wires, maybe it wasn't timed right when the new distributor went on, etc.
Any steer welcome!
Had my tech change out the distributor/rotor and I changed the plugs. Also jiggled the plug wires (which are old) but that didn't change things.
Was wondering if it might be the plug wires or something else I missed...like the plug wires, maybe it wasn't timed right when the new distributor went on, etc.
Any steer welcome!
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Joined: Apr 2009
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2007 ML 350 - VIN 4JGBB86E17A211020
I think I might have found the issue...
I recollect talking to a few folks about some sort of air value at the front of the air filter box that has two brass pins. It seemed to be loose so I took it off, cleaned the pics and female fittings.
Upon starting it up the idle was much better. Will go back in and clean it again with some contact cleaner to further improve things...
This happen to anyone else?
Upon starting it up the idle was much better. Will go back in and clean it again with some contact cleaner to further improve things...
This happen to anyone else?
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Joined: Apr 2009
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2007 ML 350 - VIN 4JGBB86E17A211020
Sensor location
Hi DocWalla...here is what I did.
Opening the hood and facing the engine, there is a plug with wires coming out of it at about the 4:00 or 5:00 position on the air filter box. Its a two piece plug: one part has a female connector with two pins and other has a cylinder with openings that goes right into the air filter housing with a twist fitting.
If you squeeze the plug and rotate it 90 degrees counterclockwise the entire plug comes out. I cleaned the area around the inner plug where it goes directly into the air filter box as well as cleaned some corrosion off of the pins that went into the female fitting. In addition, I cleaned around the hole that went back into the air filter box as mine tends to accumulate a little grease there.
I put the outer plug with the female connector back into the pins and then twist fit both plug components ( in typical MB fashion it has raised edges to fit into slots in the air filter housing) back into the air filter housing.
Started it up, still a bit of a minor burble (it does have 228K miles) but it idles much better than the rough pops I was getting beforehand.
I recollect a number of years back stopping by our local MB repair shop with the same issue. He pulled this sensor out, cleaned it with a small towel, put it back in and the issue went away.
If this text doesn't work for you let me know and I can take some pics and attach them here...
Opening the hood and facing the engine, there is a plug with wires coming out of it at about the 4:00 or 5:00 position on the air filter box. Its a two piece plug: one part has a female connector with two pins and other has a cylinder with openings that goes right into the air filter housing with a twist fitting.
If you squeeze the plug and rotate it 90 degrees counterclockwise the entire plug comes out. I cleaned the area around the inner plug where it goes directly into the air filter box as well as cleaned some corrosion off of the pins that went into the female fitting. In addition, I cleaned around the hole that went back into the air filter box as mine tends to accumulate a little grease there.
I put the outer plug with the female connector back into the pins and then twist fit both plug components ( in typical MB fashion it has raised edges to fit into slots in the air filter housing) back into the air filter housing.
Started it up, still a bit of a minor burble (it does have 228K miles) but it idles much better than the rough pops I was getting beforehand.
I recollect a number of years back stopping by our local MB repair shop with the same issue. He pulled this sensor out, cleaned it with a small towel, put it back in and the issue went away.
If this text doesn't work for you let me know and I can take some pics and attach them here...
Thread Starter
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Joined: Apr 2009
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2007 ML 350 - VIN 4JGBB86E17A211020
Let me know how things go....
I should have also passed on that I had trouble with the second spark plug from the back...felt like it was binding when I was loosening it...so to err on the side of judgement I left it in.
I will replace it this week when I feel a bit more brave....replacing 3 of 4 spake plugs did benefit...but I still have a bit of a small burble.
I will replace it this week when I feel a bit more brave....replacing 3 of 4 spake plugs did benefit...but I still have a bit of a small burble.
