ML320 Engine problem...Please Help!
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Joined: Aug 2004
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ML320 Engine problem...Please Help!
Hello, I am a new member to your site. I am hoping that some experts out there might be able to help me diagnose a problem I have been experiencing. My '99 ML320 has 76K miles on it. All regular maintenance has been performed by Mercedes up to and including 60K mile service. The spark plugs were part of the last service. They would now have 15K miles on them. They were replaced with Bosch plugs just like from the factory.
I noticed yesterday the engine was missing like a cylinder wasn't firing from the moment I started the car. It doesn't seem to make any difference what temp the car is running, it is consistenly missing even after it has reached running temp. The check engine light has never come on since this problem has occurred. I pulled all the ignition wires and tested them with a multimeter. All were between 2100 and 2300 except one which was only 8.9 so in other words basically a dead wire. Rather than messing with replacing only one wire I replaced the entire set with new wires. I am still having the same problem even with new wires. Took it over to a buddies house who is a mechanic (but not a Mercedes mechanic) who said he thought that a fuel injector may be clogged. I know Mercedes doesn't recommend using fuel injector cleaner but I dumped a bottle of Valvoline cleaner into the tank anyways to see if it helps out.
I drove through the McDonalds drive through today and since I was right up against the wall I could more easily hear the engine sound reflect back to the car. I could hear a fluttering sound come from the engine which definately is a wierd sound and overall it just has no power. Under heavy acceleration on the highway it almost sounds like a Chevy small block V-8 with a manifold leak or something. That's about the best description I can come up with as to how it sounds. I can smell gas fumes after I've parked it in the garage which isn't normal.
Any ideas? Thanks in advance!
John
I noticed yesterday the engine was missing like a cylinder wasn't firing from the moment I started the car. It doesn't seem to make any difference what temp the car is running, it is consistenly missing even after it has reached running temp. The check engine light has never come on since this problem has occurred. I pulled all the ignition wires and tested them with a multimeter. All were between 2100 and 2300 except one which was only 8.9 so in other words basically a dead wire. Rather than messing with replacing only one wire I replaced the entire set with new wires. I am still having the same problem even with new wires. Took it over to a buddies house who is a mechanic (but not a Mercedes mechanic) who said he thought that a fuel injector may be clogged. I know Mercedes doesn't recommend using fuel injector cleaner but I dumped a bottle of Valvoline cleaner into the tank anyways to see if it helps out.
I drove through the McDonalds drive through today and since I was right up against the wall I could more easily hear the engine sound reflect back to the car. I could hear a fluttering sound come from the engine which definately is a wierd sound and overall it just has no power. Under heavy acceleration on the highway it almost sounds like a Chevy small block V-8 with a manifold leak or something. That's about the best description I can come up with as to how it sounds. I can smell gas fumes after I've parked it in the garage which isn't normal.
Any ideas? Thanks in advance!
John
Last edited by johng_22; Aug 10, 2004 at 10:11 PM. Reason: Edited with a more detailed description
MBWorld Fanatic!
Joined: Nov 2001
Posts: 4,260
Likes: 6
From: Philadelphia area
2010 ML550, 2010 E350 4M, 1966 Corvette Convt C2
You have one cylinder not fireing. Determine which one and check the ignition module for the correct current being put out. You may also have a plug that has failed.
