fakebreakr

Hey guys (and gals). Long time lurker, first time poster. My 03 C230K has been trouble free for the first 73k miles, and now all of a sudden she wants to go all berzerk on me lately. And before I get flamed, I did a search prior to creating this post.......

Some basic specs on the car: Completely stock 2003 C230K coupe with around 73k miles. All schedule A/B done on time, mid cycle oil changes performed, $12 hose replaced.......

Problems first started when I threw my FIRST CEL at 73k miles followed by some rough idling. My indy pulled the codes, and turns out the major active fault was a misfiring cylinder (#2). He does the coilpack switcharoo with another cylinder to verify, finds out that the coilpack is indeed bad, and replaces the bad coilpack.

About 200 miles later, CEL comes back on, followed by rough idling. I discovered that if I shut the engine down and restart it, the engine runs smoothly again, but the CEL remains on and I can get another 40 miles or so before the rough idle comes back - which believe me is completely bizzarre.

So I bring the car back to the indy, he pulls the codes, and he sees 2 coilpacks are now faulty, engine running lean, etc etc. He reaches out one of his contacts at MBUSA, who sends him so documentation to help solve the issues my car is showing. MBUSA recommends replacing the coilpacks (done), replacing the fuel injectors, and if all else fails, decarbon the cylinder head (which supposedly costs a couple grand based on estimate from my mechanic).

So I'm left wondering 1) Why do the coilpacks keep on getting burned up 2)Would replacing the fuel injectors and dumping another $500 dollars solve the problem and 3)What other possible reasons could be causing this issue?

Sorry for the long story, just thought I'd ask the forum for their collective expertise and thoughts on this car which is becoming a money pit of sorts.....

NilssonTuning

You'll find that many parts will fail as groups. For example wheel bearings. If they were all built to the same specs and installed at the same time and one goes out, you can expect the others to do so pretty soon as well. It's simply because they all have approximately the same amount of use. In your case you have a set of coilpacks that have seen about the same amount of use and are wearing out. My recomendation is to replace the remaining old coilpacks.

I don't see how injectors could affect coilpacks. What MBZ gave your tech sounds like a checklist of issues for him to run through instead of someone telling him, "ya we've had the same issue with other cars, the problem is ____." In addition you've confirmed that the other packs are bad anyway so don't have anything to lose. Furthermore I don't see predetonation caused by carbon buildup on the head as something that would go away by simply cycling the ignition on and off.

C230 Sport Coup

Coil packs on the 4 bangers sit right on top of the spark plugs, get cooked, and generally
have a finite lifespan, tend to go in groups. I speak from experience.
Best to do them all at once, and easy DIY for about 140 bucks.
I had the same thing, one went at 55K, then again at 75K, but rather than go to the dealer, have them do one, I did the remaining 3 and just paid out of pocket about 110 bucks rather than deal with the dealer, and all day affair etc. The one that was replaced at 55K, failed like clockwork, another 55K miles later at 110K.
Now I always keep a spare in the car. Sux driving on 3 cylinders.
Just recently, I got a CEL on #4, and put dielectric grease on all 4 CP's as I had not previously.
Seemed to help a little...though I suspect it's on the way out.
Again, like clockwork, 137K miles, what, just 55-60K since the last replacement.
Thankfully they're only about 40 buck each including shipping.

Make sure to put dielectric grease on the point of contact with the plug, it'll help to
ensure maximum life on the CP's.

I don't think you should have any reason to replace the FI's.
Thats BS.
But pray you don't have the bad head issue of 2003.

If you did have an FI issue, they can be professionally cleaned, check around, there's folks here that have done it.

The thing with turning the key and off is normal.
When the ECU senses a misfire, which actually it has to sense multiple misfires based on a calculation of X # of misfire per total fires, it shuts the fuel off to the offending cylinder (for smog), throws a CEL to tell you which cylinder, and when you stop and restart, it resets. But keeps the CEL, which can be read and cleared with any OBD reader.

fakebreakr

I do recall a post you made about the dielectric grease on the coilpacks. I'll tell my indy about that.

The bad head issue of 2003? Looks like I need to do some more searching......

C230 Sport Coup

Make sure he replaces the 4th CP.
Do you want to go through this yet again?

fakebreakr

Update: FI replacement didn't change a darn thing - just like everyone thought. Coilpacks are still being burned up like no other - he had to replace the same 2 CP's that keep on failing. So those 2 cylinders have burned up a total of 5 CP's in a little over 2 weeks.

Indy is going to pull the head and check it out the internals based on his own irritation with the car and the challenge its causing him. He really wants to solve the problem for his own sanity.

I want to lean towards something with the ignition system causing the issue (bad ground, voltage spikes, bad connector, short in the system, faulty modules, etc) since i like to think electronic "boxes" will tend to fail before something mechanical does.

What I'm afraid of is the bad head problem - especially since im way out of warranty.

mleskovar

I don't have a 4 cyl but these symptoms don't sound like a lack of spark. That would make it run rich unless I'm missing something. I know coil packs are a high failure item on the 4 cylinder but you ran 73K miles OK, and then started eating them. What do the plugs look like? If they're oily then you do have the dreaded head/worn valve guide problem. When the coil packs fail, what is the failure? Are they open or shorted (to ground or internally)? Has anyone put a meter to a new and 'failed' coil? Also, have you tried cleaning the MAF? Just throwing out some ideas and easy things to do, it sounds like you aren't having fun anymore with your car.

C230 Sport Coup

Yeh, once he pulls the head, he'll have you over a barrel.
He can tell you anything, and unless you want to have it towed out, with a box of parts in the trunk, you'll be screwed. You could be looking at thousand of dollars in repairs.
It's not likely the coil packs were actually bad if they were replaced with new ones.

I'd be wary of this mechanic, especially if he hasn't checked the plugs.
Thats something you'd need right around this time, ie new plugs,
and cleaning the MAF is essentially free, just the cost of the cleaner.
I do mine about every 20K miles or so, plugs every 60K miles.

And as said previously, there was absolutely no precedent for him to be changing the FI's.
I have 135K on mine, that isn't a part thats prone to problems until much later or at all as far as
I can recall....can't recall anyone here having a problem and solving it with new injectors.
One guy sent his out for cleaning and noticed an improvement in power, but the car was still running fine beforehand.

If I were you, put the whole thing on hold, till you get a better handle on the situation,
and possibly a 2nd opinion.

phate

What was his reasoning for pulling the head? It kinda sounds like he's out of viable solutions.

I am not familiar enough with the Mercedes ignition system but mleskovar brings up a good question. What makes the coils bad (open or shorted)? Have they checked the timing and dwell throughout the entire rpm range (too much dwell will burn up a coil very quickly)? Does Mercedes use individual cylinder control for their ignition systems (it sounds like they do for fuel)?

C230 Sport Coup

Sounds like he's trying to hold onto his cash cow by tearing sh_t down, and then
telling him what it's gonna cost in 4 digit numbers to put it back together.

tevbax

Im actually having the same issue as you. But, im not getting coil pack failure on the go. Ill start up in the morning.... misfire. Key off, restart.... no more misfire. Sometimes shell jsut do the runs rough for 30 seconds.... sometimes shell throw a CEL for the #2 cylinder misfire. Ive swapped coils, and shes stayed in cyl. 2. I havent changed the plugs yet.... but thats what was suggested to me earlier and this morning. Ill update with what happens after my plug change.....

dmatre

If I recall correctly, most of the folks here with the head problem had misfire in cylinder #4. Also, this would have no relation at all to coil packs failing.

Hope that it gets straightened out soon.

sghokie

maybe the engine isn't grounding properly.
The coil packs themselves must be grounded as does the base of the sparkplug.

amanonfire

I've had that before, changing the plugs solved it.

tevbax

I changed plugs, still no go. Took it over to my buddies shop today... Blown head gasket leaking coolant into #2 cyl causing the misfire.

Should have never bought a Mercedes.....

SeaCoupe

At this point do we make it official? The 2003 M271 engine sux.

Glyn M Ruck

It's Official - The 2003 & in some markets early to mid 2004 M271 engine sucks - Crap head - It's more prevalent in the C230 state of tune but the 200s & C180s have the same nonesense. We had a lady in the family with a C180 that went through 4 heads in 120,000 Kms at +30,000 Rands a pop - That's US$ 3000 per head. Benz paid for 1. Fortunately it was a company car and they paid for the other 3.