C-Class (W203) 2001-2007, C160, C180, C200, C220, C230, C240, C270, C280, C300, C320, C230K, C350, Coupe

Yet Another Misfire Thread, with a couple extras.

Old Feb 16, 2019 | 06:18 PM
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Ian LoveH8Benz's Avatar
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From: Milton Vt
2007 C280 4Matic + 2001 C320 RWD
Unhappy Yet Another Misfire Thread, with a couple extras.

Hi Guys,
Been a long time lurker here, solved quite a few small problems on my 2 lovely C-Classes thanks to this forum. Well now I have one, that is seemingly complicated enough that I'm going to need a little more precise guidance if there is any to be had.

The car in question, 2001 C320 Automatic, 112,000 or so miles (too many cars with similar numbers here), RWD. Had it for about 3 years or so, (incidentally also my first car, but not the first i have ever worked on)

So, a little backstory.
Seemingly since the day the car came home, she's had a little bit of a rough, shaky idle. Seems to be some oil leaks from the small gaskets above the coil packs.
Also, when you really step on the pedal, up comes a cylinder 6 misfire P0306, and only that code, and all the associated symptoms (power loss, feels like your in a paint shaker when idling, CEL) Restart car, symptoms go away, CEL stays.
Replaced all 12 plugs, and a brand new coil pack on Cylinder 6. Made the problem a little less sensitive, but still there.
Or at least thats how she was acting.

So the last 2 months have been "Fun", Unfortunately I had to do a classic, Change the battery, then get the car inspected, including OBDII Emissions. Naturally it failed, oh Mini rant but here in VT you are not allowed to have ANY I/M Readiness flags incomplete as of January 15 2019. (So much for the 1 your allowed by EPA). So the last 2 months have been spent trying to get it to complete the readiness indicators. EVAP being the one that just wont take. (this being the 3rd go around due to misfires and mistakes). Real fun considering the car was due to be inspected in December... and has to be driven to get things to work...

Anyways, the symptoms have changed BIG TIME as of yesterday. Took it out for a drive to try and get this evap to clear (nope, the 20 min Idle in the driveway hasn't cleared it after 5 tries... even pulled the air box and ducted cold air for the intake temp....)
So, driving up our lovely 2 laners, everything is fine. Go to pull to a stop to turn the corner. *Cough Cough* uhm.... no power, no acceleration, car sputters around the corner for 5 seconds, then takes off. Next corner Same problem. Wash Rinse and Repeat. Rev it a bit on the highway, CEL, pull over and read codes, then cleared. Go to get it up the driveway (500ft, fairly steep grade, add some ice) and she nearly dies at the hillcrest... (No CEL)
Ordered a new fuel filter, Mann WK 720. Plugged it in today (what a pain) A bit better, for a bit. Took it for a drive, floored it, got CEL, restarted car and took it back out, now the slow powered deathtrap is back. Get it home, turn it off for about 5 minutes then start it up, about 30 seconds of sitting hard revving the car to try and trip the CEL, nothing. Then try to rev it again, Cough and Sputter, feels like its gonna choke, then Revs, repeat throttle down, repeat symptoms.
Unplugged MAF, idles slightly easier, same symptoms though. MAF Looks clean (almost suspiciously), gonna clean it next. Also was watching the datastream from my Carsoft MBII, and with the MAF unplugged i was still watching the values update, but the Intake air temp was stuck at -40C, is this normal?
So The codes i pulled on the highway,
P0303 Cylinder 3 Misfire
P0304 Cylinder 4 Misfire
P0300 Random/ multiple misfires detected

After the fuel filter was Cylinders 1 and 4 i think? Plus the multiple/random. Foolishly assumed they were the same as the highway run...

Worth noting at this point that there was a couple codes in the Me2 SFI motor electronics, I have no idea how old they were, but clearing them did make me have to redo the emissions... again.... (that was try 2)
they were (and havent come back)
P20d4-008
P20d4-002
Something about Load limit active, searched on it, didn't get a whole lot of enlightenment.

Sadly for the past year or so, this car hasn't seen a lot of miles, Since I acquired the lovely C280 4matic I have listed (Funny story how I ended up with that one). Just haven't been able to sell it for about 100 reasons that keep coming one after another.

any enlightenment would be most appreciated. Want to get this car back up and running so it can see a good home. but if she keeps this nonsense up, i'm afraid she may be headed for a scrap yard... Door rust, high miles, yeah she's not worth much.

Side Note: Ill probably launch a new thread for this, but the C280 has that grinding thing in the transfer case when you make a right turn, and an odd clunk (from the trans?) when taking off from a stop. Dealer records indicate that the previous owner had 2 gear oil changes done it and its back. Is there some kind of replacement campaign on this thing? and should I be worried about it suddenly seizing up or failing to transfer power at all one day? or is it just one of those nuisances that can be left alone.

Thanks, and sorry for the long winded post
Ian
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