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I've gone through and replaced about 5 coil packs now over time on my engine due to them causing misfired/failing at higher rpms. The problem goes away for a while until another one goes bad on me.
I have to think there is some underlying issue, as Ive tried replacing them with both cheap aftermarket and genuine OEM and they fail at about the same rate of one every 3-4 months. Any idea what might be causing this happen?
Could it be from a bad ground on the engine or other wiring issue?
C230 Sport Coup + 2006 W164 ML350 + 99 Ford Escort (What the heck, it gets 38 mpg!)
Had the same problem. I have a large collection of those damn things.
The real issue is the plugs.
As they wear their resistance increases and stresses the CP's.
After buying about 10 CP's and thinking that was the issue, a mechanic told me
to replace the plugs. They don't last as long as advertised.
Fact is once you replace the plugs, you will likely find that you can reuse most if not all of the coil packs
that "failed". Go with the NGK laser iridiums (Same as what Mercedes sells).
I've been through 'em all. I tired the Iridium IX's (garbage)
and copper too based on some advise from the guys in the SLK forum, since I share the same engine.
In the end I went back to the NGK laser iridium 5344's $35 with free shipping on ebay.
Since you have 1.8L probably a different part number.
Plan on changing them every 30-40K miles top, because though they say they'll last 100K that's total
BS. Or just change them the minute you start getting misfires due to what seems to be coil packs.
And just to be safe, keep a spare CP in the car. It's true they do get cooked sitting on top of the engine, and
I've had a few that cracked open and failed. But mostly it's the damn plugs. As far as I know there are no wires
with these. Just sit right on top of the plug vs. like a 3.2L which has plug wires.
Had the same problem. I have a large collection of those damn things.
The real issue is the plugs.
As they wear their resistance increases and stresses the CP's.
After buying about 10 CP's and thinking that was the issue, a mechanic told me
to replace the plugs. They don't last as long as advertised.
Fact is once you replace the plugs, you will likely find that you can reuse most if not all of the coil packs
that "failed". Go with the NGK laser iridiums (Same as what Mercedes sells).
I've been through 'em all. I tired the Iridium IX's (garbage)
and copper too based on some advise from the guys in the SLK forum, since I share the same engine.
In the end I went back to the NGK laser iridium 5344's $35 with free shipping on ebay.
Since you have 1.8L probably a different part number.
Plan on changing them every 30-40K miles top, because though they say they'll last 100K that's total
BS. Or just change them the minute you start getting misfires due to what seems to be coil packs.
And just to be safe, keep a spare CP in the car. It's true they do get cooked sitting on top of the engine, and
I've had a few that cracked open and failed. But mostly it's the damn plugs. As far as I know there are no wires
with these. Just sit right on top of the plug vs. like a 3.2L which has plug wires.
Ah, interesting theory. That would make sense as last time I changed the plugs in 2015, I used NGK (6619) LFR6AIX-11 Iridium IX Spark Plugs which are supposedly pre-gapped (I didnt double check) and this issue has been happening ever since. I will plan on replacing them soon with the NGK laser plugs and see if that clears up the misfires. Thanks!
The OEM plugs for the M271 are the ones you listed, NGK LFR6AIX-11. They come pregapped out of the box and do not need adjustment at all.
Bit of a dumb question, but when you changed out the plugs, did you apply dielectric grease, and if you did, did you only apply correct (ceramic) part? If you got any on the metal terminals that would increase the resistance between the plug and ignition coil.
C230 Sport Coup + 2006 W164 ML350 + 99 Ford Escort (What the heck, it gets 38 mpg!)
The iridium IX are GARBAGE. I went through god knows how many sets of these before I wised up.
I never got more than 30K miles on those without a coilpack "failing". Figure on changing those every 25K. Copper every 15K. The Lasers no more than 50K if you can go that long with a coil pack seeming to fail. My 1st misfire issue occurred at 54K miles. It was under warranty, and I wasn't as edumacated on all things Mercedes
back than and it went to the dealer. What did they do? Replace the plugs.
This is no theory. Guaranteed fact! I've got 245K miles and been through more spark plugs and
coils than....uh....trying to think of something clever....uh...brain not working today. I been through more plugs than a farm dog has fleas...got that off this website. https://www.texasmonthly.com/article...ke-a-stick-at/
Oh yeah, and Slammers right...make sure you use some dielectric grease between the top of the plug and the coil. And per that mechanic I put a drop of trans fluid on the threads. That graphite **** gets all gunked up like glue over time.
Last edited by C230 Sport Coup; 09-20-2018 at 02:38 PM.
The OEM plugs for the M271 are the ones you listed, NGK LFR6AIX-11. They come pregapped out of the box and do not need adjustment at all.
Bit of a dumb question, but when you changed out the plugs, did you apply dielectric grease, and if you did, did you only apply correct (ceramic) part? If you got any on the metal terminals that would increase the resistance between the plug and ignition coil.
I don't believe I did that... that would be dumb if I did but wouldn't it past myself tbh if I wasn't paying attention. Think I followed a guide on here but I will know for sure when I replace them in a week or so.
Originally Posted by C230 Sport Coup
The iridium IX are GARBAGE. I went through god knows how many sets of these before I wised up.
I never got more than 30K miles on those without a coilpack "failing". Figure on changing those every 25K. Copper every 15K. The Lasers no more than 50K if you can go that long with a coil pack seeming to fail. My 1st misfire issue occurred at 54K miles. It was under warranty, and I wasn't as edumacated on all things Mercedes
back than and it went to the dealer. What did they do? Replace the plugs.
This is no theory. Guaranteed fact! I've got 245K miles and been through more spark plugs and
coils than....uh....trying to think of something clever....uh...brain not working today. I been through more plugs than a farm dog has fleas...got that off this website. https://www.texasmonthly.com/article...ke-a-stick-at/
Oh yeah, and Slammers right...make sure you use some dielectric grease between the top of the plug and the coil. And per that mechanic I put a drop of trans fluid on the threads. That graphite **** gets all gunked up like glue over time.
Thanks for all the advice!! Much appreciated. Ordered the non-garbage laser ones you suggested last night off ebay (for my car they were NGK 3588). I'll report back after install (double checking gap this time) and a bit of a stress test.
C230 Sport Coup + 2006 W164 ML350 + 99 Ford Escort (What the heck, it gets 38 mpg!)
Yup, anytime I have an issue with misfires these days, I just change the plugs and
I haven't bought a single coil since.
Still have a new one I keep in the car, but haven't needed it.
I think I must've purchased a dozen of them before that mechanic gave me that sage advise.
While the plugs might still work, they put too much stress on the coils.
And a new coil will solve the problem, but then you end up having "coil"
issues almost constantly till the plugs get replaced.
Quick update. It was worse than I could have imagined... Not only were my plugs worn and covered with oil but it seems that the misfires were a leadup symptom of the infamous timing chain issue. Car was idling rough today and surging and misfires and P0010 code then finally wouldn't start any longer. Turns out my intake cam sprocket is completely worn down and chain probably skipped a tooth. I'll post pics tomorrow, but I took my valve cover off to inspect how far it's off by and need to check if valves are bent. I know there's a ton of threads on this already but my plan of attack is get a 27mm socket to manually turn the pulley (clockwise?) until it reaches TDC and compare with the lines on top of the two cams. Check compression with a tester kit I have. And maybe examine inside with an endoscope camera. If there's not interference damage, proceed with ordering this kit. https://www.ebay.com/itm/For-Mercede...EAAOSw0j9ZSMZl
Yikes I shouldn't have put this job off but an indie I talked to convinced me it wasn't as prevalent. Now I know better and hopefully its salvageable.
Last edited by pm93; 09-24-2018 at 02:42 PM.
Reason: changed link and corrected a few words
C230 Sport Coup + 2006 W164 ML350 + 99 Ford Escort (What the heck, it gets 38 mpg!)
Holy Sheit! Right hand sprocket in pic is just gone....
I would use genuine parts.
Order online http://mercedesbenzstarparts.com/
is Steven Creek Mercedes in San Jose and you can specify counter pickup and
they'll subtract the shipping. Wholesale prices, but you pay the tax.
They really hate it that anyone found their secret website...ha, since at the counter they charge 3x list and on the website, they charge -25% list and more!
Or oediscountparts.com from back east, another dealer, free shipping and no tax,
but takes a week.
150k Miles / 240km
I've got all the parts and special tools needed and I'm thinking this weekend will be my best time to work on it. I will be sure to post some pics.
Was wondering if anyone can point me to a guide on changing the camshaft sprockets? I have an idea of what to do up until the chain however the sprockets haven't been well documented online.
Some updates... After a lot of delays and mistakes (first time doing something like this DIY) here's where I'm at. Camshaft sprockets were changed out for new ones. Had to use vice grips to lock the camshaft in place at the notch as the chinese clone specialty tools were useless. Attempted to run the new chain through the engine but the temporary link I was using wasnt strong enough and detached. I sorted that out by using a grabber tool and safety wire to grab the old chain which thankfully means I don't have to disassemble more of the timing panels off the engine. Tried again to run the chain through, but was having problems with the crankshaft sticking at a certain point like the valves were open. Also the special $100 nut holding the sprockets for the adjuster magnets randomly broke off when I lightly bumped it. New plan is buying the replacement camshaft nut, using a nail as a temp link for the chains, taking the camshaft cover off so that all valves are closed (and not worrying about the valves staying in sync), running chain through crankshaft and going from there. Like I mentioned earlier, I will post pics at the very end when its back up and running. Thanks all.
Chain is back on. As I suspected, pulling the chain through without the camshafts on this time was MUCH easier and I HIGHLY recommend you take off the cover with a cordless impact as there are a ton of bolts. Use safety wire to hold onto the chains so they don't drop into the engine. The aftermarket timing chain tool kit is USELESS and I ended up not using any of the tools from it. Engine hand cranks just fine and timing is back right on the mark. I wasn't satisfied with my generic chain riveting tool, so I bought a version that supposedly works for these specific timing chains (another $70) and will wait until it arrives Saturday to proceed. Here are some more photos!
Edit: More tips I can think of that I did... stuff shop towels down gaps whenever you think you might drop something accidentally. Be very careful around the $100 nuts on the adjusters as the part that sticks out to the magnets is quite fragile. Big vice grips help with locking the camshafts in place when you change the adjusters (metal score doesnt really matter because where the lock doesn't contact the valves). If you don't have a temp chain link, use a nail cut to size. When it comes time to tension the chain, you can move the exhaust cam back a couple teeth, hook it onto the chain, and then pull it forward to get a little extra leverage as the chain tensioner needs to be a little compressed.
09-18-2018, 07:29 PM
Much appreciated. Ordered the non-garbage laser ones you suggested last night off ebay (for my car they were NGK 3588). I'll report back after install (double checking gap this time) and a bit of a stress test.
