bth1969

intermittent misfire on #1,replace coil, misfires now on #3, reads 11 to 13 misfires, then put #1 coil in #3 spot and misfire goes down to 1 on #3 cyl.
Do you think it's just another marginal coil on #3 or is there something else that might cause a possible low voltage condition on the right bank of coils? Ther were no misfires on #3 before that I saw and no codes triggered.

terryc230

I had a similar issue with my 2006 C230. Turns out it was one bad coil pack and on another cylinder, when i replaced the spark plug, it apparently fell from the spark plug socket to the bottom and messed up the spark plug gap. I pulled and regapped the plug and cleared the code. So it could be the coil pack or something else like a spark plug issue.

Terry

slammer111

If in doubt, just replace both #1 and #3 coils. They're not expensive at all.

C230 Sport Coup

Spark Plugs do not last as long as advertised.
With the fancy Iridiums that come on the car, ie NGK's
I'd say every 40K miles.
Iridium IX 25K and copper, 15K.
I've used 'em all.

Back to the stock plugs 40 bucks on ebay.

When you start getting misfires, change the plugs.
I've got a large collection of coils....
turns out most of them are perhaps marginal with old plugs, but fine with
newer ones.
Plugs are cheaper than coil packs.
Always keep a spare coil pack though and an 8 mm wrench (well actually it's inverted torx but 8mm works in a pinch and an allen...no fun driving on 3 cylinders and not a part easy to find when you're on the road.
Also be sure to use that conducting grease on the contact between the plug and the coil

bth1969

Thanks everybody, I had already changed the plugs, a little late, Last changed at 74k, now at a little over 155k. Most likely just more than one coil pack bad and really would normally have replaced all coil packs and wires at the same time but just a little shy of funds at the moment. So, for now I'll just get another used pack with wires till the next pay day. then replace them all. This is my first MB and just got it a year ago. Used to work on older ones and hated them but really like the newer offerings . The next one will be a E55.

C230 Sport Coup

Ah,, yes, wires and coils.
C230 has coils directly on top of the engine and they do tend to get cooked.

Thursty

When I needed to do ignition coils for our C230 I found Beru coils on Amazon for less than $40 each. Beru makes the coils for Mercedes, in fact, all of my factory coils say Beru and have the Mercedes star on them, part numbers were even the same. I've had iffy experiences with the auto parts store generic coils, plus the price is similar, so why not get legit OEM. So, I would look for Beru coils online, and see if you can find them in a 4 pack. I've found that when one fails, others will follow.

Richard Wraith

Check the coil packs as they tend to get small fracture's & cause the spark to find an earth. So what you have to do is pull the coil packs out, check for very tiny fractures/cracks & insulate them with Self amalgamating tape or clear nail polish, even silicone, just make sure they're insulated & it will work fine.

bth1969

Thanks, that is the tip I was looking for. I did find 6 used coils for $37. that will keep me going for a while, (got car with 128k One yr later at 155k), My first MB, I actually like working on it. So far it has been easy and cheap except for double the cost of plugs & wires. Repairs to date: front suspension, rear springs & adjustable camber arms, rad hose, AT205 for rear main seal, hvac controls (permanent fix using spring hose clamps, trimmed tabs, around plastic socket), alternator, tune up, F wheel bearings & brakes, and crank sensor.