Num 6 cylinder acting up
Thread Starter
Newbie
Joined: Dec 2002
Posts: 6
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From: Atlanta
1996 c280
Num 6 cylinder acting up
My 1996 c280's #6 cylinder keeps misfiring, I replaced the nearly-new sparkplugs with bosch platinum +4's and it is STILL misfiring. What could be my problem?
Thread Starter
Newbie
Joined: Dec 2002
Posts: 6
Likes: 0
From: Atlanta
1996 c280
coil/wires
My mechanic told me it was my supressor end, so I replaced that, however, it still misfires... I was wondering how bad coils or wires could fire good half the time and not the other half, shouldnt they be bad no matter what?
Thread Starter
Newbie
Joined: Dec 2002
Posts: 6
Likes: 0
From: Atlanta
1996 c280
stock plugs
I had stock plugs in there which are bosch platinum plus (+1) when i changed them out with the new ones, it started misfiring, although it misfired once at the autocross after my final run on dec 15 when i still had the stock plugs in there....
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Joined: Dec 2002
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Same thing happened to me. 6th cylinder misfiring. Couple weeks later my car started to spew out white smoke. Warped cylinder head. 4k CAD out the window to get that fixed.
Have you replaced the plug wires and/or ends?
Have you replaced the plug wires and/or ends?
Thread Starter
Newbie
Joined: Dec 2002
Posts: 6
Likes: 0
From: Atlanta
1996 c280
the wait...
Thanks for your information regarding the subject, and seeing as though the c36 engine was actually built from the c280 engine (redesigned by amg with new headers etc etc....) I dont think the ignition systems would be too different. I replaced the supressor end on num6 cylinder and all the plugs, however, the wires are a different story.... I have not driven the car any more than 3 times since it happened a week ago and my appointment with the dealership to get it fixed is on the 26th... What pisses me off most is that this happened TWICE on two seperate occasions when my mom drove the car (its a hand-me-down) and the dealership said they fixed the problem last time....
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Member
Joined: Mar 2002
Posts: 180
Likes: 1
From: Southern California
93 300E
Mis-fire problems are almost always ignition related.
Take out your platinum plugs. This engine was not designed to run on platinum plugs. The electrode on platinum plugs is too small. Most technicians will not diagnose a car unless it has the original Bosch copper core non-resistor plugs. Make sure the gap is correct. If the gap is too big it will also cause a misfire.
Your engine has 3 coil wires and 3 high tension leads that piggy back from each coil wire. So, each coil wire is responsible for firing two cylinders. Your coil wires are solid copper and rarely go bad. Most people make the mistake of replacing them with Bosch wires at the local parts store because they are cheap. These are not good as they are a silicone / copper blend and wear out. Go ahead and replace the three resistor boots on your three coil wires. The resistor ends are about $7 each.
If this doesnt' work, then replace your coil wires and the high tension leads with a new set from the dealer. If they don't have the Mercedes Star symbol on them, don't use them.
Take out your platinum plugs. This engine was not designed to run on platinum plugs. The electrode on platinum plugs is too small. Most technicians will not diagnose a car unless it has the original Bosch copper core non-resistor plugs. Make sure the gap is correct. If the gap is too big it will also cause a misfire.
Your engine has 3 coil wires and 3 high tension leads that piggy back from each coil wire. So, each coil wire is responsible for firing two cylinders. Your coil wires are solid copper and rarely go bad. Most people make the mistake of replacing them with Bosch wires at the local parts store because they are cheap. These are not good as they are a silicone / copper blend and wear out. Go ahead and replace the three resistor boots on your three coil wires. The resistor ends are about $7 each.
If this doesnt' work, then replace your coil wires and the high tension leads with a new set from the dealer. If they don't have the Mercedes Star symbol on them, don't use them.
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Member
Joined: Dec 2002
Posts: 173
Likes: 0
From: Atlanta Georgia
95 C280
I had that problem twice and i found out what hte probem was.
The spark plu that u bought had a 1.3mm gap between the two tips and my mercedes can only manage .8mm. The guy told me that its not always the bigger the better. It actually decreasedmy cars preformance.
Elvir
The spark plu that u bought had a 1.3mm gap between the two tips and my mercedes can only manage .8mm. The guy told me that its not always the bigger the better. It actually decreasedmy cars preformance.
Elvir
