M104 Ignition System Type...
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From: Bellevue, NE
1995 E320 SE, 162,000 Miles (Sold) 2007 CLK350 Cabriolet 2014 ML550
M104 Ignition System Type...
Yes, I'm too cheap to buy a repair manual on my '95 E320, but I have not been able to find one anyway.
What does the ignition system consist of on these cars with the M104 engine? I read another post that mentioned a distributor cap. I've also seen mention of a crank sensor. I thought a car either had one or the other. I've never seen any parts like a cap or coil packs or even plug wires.
My engine sometimes misfires for a split second when I get on it and I don't think the plugs have ever been replaced so any info you might have on the system architecture would be helpful.
What does the ignition system consist of on these cars with the M104 engine? I read another post that mentioned a distributor cap. I've also seen mention of a crank sensor. I thought a car either had one or the other. I've never seen any parts like a cap or coil packs or even plug wires.
My engine sometimes misfires for a split second when I get on it and I don't think the plugs have ever been replaced so any info you might have on the system architecture would be helpful.
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From: Houston, Texas
Dora the Explorer
The M104 does not have a distributor, it has 3 coils that run two plugs each. The plugs are located beneath the center of the valve cover. The coils are friction fit over 3 of the plugs. Just be very careful if you still have the original wiring harness, because you can really f it up with all of the movement during a spark plug change.
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MBWorld Fanatic!
Joined: Dec 2006
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From: Bellevue, NE
1995 E320 SE, 162,000 Miles (Sold) 2007 CLK350 Cabriolet 2014 ML550
Thanks Matt! I took out one of my plugs and it appears to be original, with 157,000 miles on it! It's a genuine Mercedes plug, made in france, and it had some reddish, rusty substance caked on at the base of the ceramic insulator. How long do these things last?? The previous owner had the dealer do the 100,000 mile service. I would think for the $$$ they would have at least replaced the plugs.
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From: Washington, the State
1993 300CE Sportline
100,000 mile spark plugs?
SNIP SNIP:Thanks Matt! I took out one of my plugs and it appears to be original, with 157,000 miles on it! It's a genuine Mercedes plug, made in france, and it had some reddish, rusty substance caked on at the base of the ceramic insulator. How long do these things last?? The previous owner had the dealer do the 100,000 mile service. I would think for the $$$ they would have at least replaced the plugs.SNIP SNIP
How long do most plugs last? Is the first scheduled tune-up at 90,000? Also if you have paperwork of a tuneup at 100,000 from the dealer is there any mention of the wiring harness? You would think the dealer/repair shop would comment on the known issue of wiring harnesses. Maybe yours is okay.
Let us know the condition of the harness...be careful.
kurt
How long do most plugs last? Is the first scheduled tune-up at 90,000? Also if you have paperwork of a tuneup at 100,000 from the dealer is there any mention of the wiring harness? You would think the dealer/repair shop would comment on the known issue of wiring harnesses. Maybe yours is okay.
Let us know the condition of the harness...be careful.
kurt
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MBWorld Fanatic!
Joined: Dec 2006
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From: Bellevue, NE
1995 E320 SE, 162,000 Miles (Sold) 2007 CLK350 Cabriolet 2014 ML550
I don't have any records prior to 138,000. The harness feels stiff in places (like the wires that supply the coil packs) but the wires that I can see don't have any insulation coming off or cracking or exposed copper. There are some areas where the large rubber sleeve that contains the individual wires is split but so far I have no reason to suspect any electrical problems.
The spark plugs looked like a lot more than 50-60k miles so I figure they must have never been replaced. The electrode on the number 2 plug which I removed was not really worn but had a considerable amount of buildup on it and some hard carbon. Is spark plug replacement NOT part of recommended maintenence or did the stealership stiff the previous owner? Irritating, I don't have a shred of paperwork like the owners manual, manitenence guid, or anything; just the records since 138,000 miles. I really wonder if the main water pump has been replaced. I wouldn't think it would last this long. The aux water pump was replaced.
I e-mailed the dealer in San Antonio where it was serviced previously but they never responded.
The spark plugs looked like a lot more than 50-60k miles so I figure they must have never been replaced. The electrode on the number 2 plug which I removed was not really worn but had a considerable amount of buildup on it and some hard carbon. Is spark plug replacement NOT part of recommended maintenence or did the stealership stiff the previous owner? Irritating, I don't have a shred of paperwork like the owners manual, manitenence guid, or anything; just the records since 138,000 miles. I really wonder if the main water pump has been replaced. I wouldn't think it would last this long. The aux water pump was replaced.
I e-mailed the dealer in San Antonio where it was serviced previously but they never responded.
