Misfire that won't quit
03-19-2016, 03:51 PM
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1999 C43 AMG, 2005 E55 Wagon
Misfire that won't quit
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A buddy drove 9 hours and bought his own C43. He got it at a really cheap price because it had a random misfire the previous owner said he didn't want to deal with.
The car was featured here: http://jalopnik.com/for-3-600-this-1...per-1762606836
I read jalopnik, but it's a total coincidence that he bought this car. My friend isn't internet savvy, and has no idea what jalopnik is.
Anyway, he brought the car back and I assured him I would help him figure out the misfire.
Lucky for him, I have 2 healthy running C43's here to test with. So, we pulled codes on his car and had codes for P0300, P0302, P0304, and P0308. Random misfire, and cylinders 2 4 and 8. Cleared the codes at this point.
Replaced his MAF and entire intake with mine: no change.
Replaced coils at 2, 4, and 8: no change. CEL back on (because it was still definitely running rough and misfiring). Pull codes, and we are only getting a code at cylinder 8. After a while, got a code for random as well as cylinder 2 again.
8 is being persistent, so got new plug wires, codes, and a brand new coil on 8: still misfiring. It's definitely getting fuel, because the plugs have gas on them when I pull them out. His old plugs, coils, wires, and MAF all work fine on my car.
So, we've essentially swapped around all the typical parts and his car still has a misfire on 8 and sometimes 2.
It has an exhaust leak at the secondary cats, and when you rev the engine it's blowing faint hints of black smoke (unspent fuel) out the tailpipe. The exhaust smells *very badly* but I'm not sure if that's because it's leaking or if it's just really rotten fuel.
I have a suspicion it could be clogged primary cats? Or could the whole thing really just be terrible fuel not burning? Poor guy is very heartbroken because he was so excited to have his own C43. I've assured him we'll get it figured out but I'm kind of at a loss as to what to do now
A buddy drove 9 hours and bought his own C43. He got it at a really cheap price because it had a random misfire the previous owner said he didn't want to deal with.
The car was featured here: http://jalopnik.com/for-3-600-this-1...per-1762606836
I read jalopnik, but it's a total coincidence that he bought this car. My friend isn't internet savvy, and has no idea what jalopnik is.
Anyway, he brought the car back and I assured him I would help him figure out the misfire.
Lucky for him, I have 2 healthy running C43's here to test with. So, we pulled codes on his car and had codes for P0300, P0302, P0304, and P0308. Random misfire, and cylinders 2 4 and 8. Cleared the codes at this point.
Replaced his MAF and entire intake with mine: no change.
Replaced coils at 2, 4, and 8: no change. CEL back on (because it was still definitely running rough and misfiring). Pull codes, and we are only getting a code at cylinder 8. After a while, got a code for random as well as cylinder 2 again.
8 is being persistent, so got new plug wires, codes, and a brand new coil on 8: still misfiring. It's definitely getting fuel, because the plugs have gas on them when I pull them out. His old plugs, coils, wires, and MAF all work fine on my car.
So, we've essentially swapped around all the typical parts and his car still has a misfire on 8 and sometimes 2.
It has an exhaust leak at the secondary cats, and when you rev the engine it's blowing faint hints of black smoke (unspent fuel) out the tailpipe. The exhaust smells *very badly* but I'm not sure if that's because it's leaking or if it's just really rotten fuel.
I have a suspicion it could be clogged primary cats? Or could the whole thing really just be terrible fuel not burning? Poor guy is very heartbroken because he was so excited to have his own C43. I've assured him we'll get it figured out but I'm kind of at a loss as to what to do now
03-19-2016, 07:13 PM
#2
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check sparkplugs and check timing(chain)
see here ( just an example on ebay) for cheap do it yourself tool to check if timing is off..
http://www.ebay.com/itm/Mercedes-M11...549884&vxp=mtr
see here ( just an example on ebay) for cheap do it yourself tool to check if timing is off..
http://www.ebay.com/itm/Mercedes-M11...549884&vxp=mtr
03-20-2016, 05:44 AM
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99 C43 AMG, 01 ML55 AMG, 05 C55 AMG, 02 CLK 55 AMG, 99 Slk 230, 03 SLK 230, 02 C230k, 98 C230
The add states the cats are gutted. Maybe misreading of 02 sensors. Also check for any vacleaks and def fix the exhaust leak.
03-20-2016, 11:16 AM
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1999 C43 AMG, 2005 E55 Wagon
The primary cats appear untouched, but I can see fresh welds on the secondary cats. This leads me to believe the primary cats are still in-tact and could be clogged, causing this issue.
With his car and one of my cars both at operating temp and idling side by side, I used a digital IR thermometer and got some weird readings off his exhaust before and after the cats. His left side (with the misfire) wasn't getting as hot, obviously.
But I noticed a much higher difference in temp pre and post cat on his versus mine. There was maybe a 20 degree F difference on my car, but over 85 degree difference on his.
With his car and one of my cars both at operating temp and idling side by side, I used a digital IR thermometer and got some weird readings off his exhaust before and after the cats. His left side (with the misfire) wasn't getting as hot, obviously.
But I noticed a much higher difference in temp pre and post cat on his versus mine. There was maybe a 20 degree F difference on my car, but over 85 degree difference on his.
03-23-2016, 08:33 AM
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1999 C43 AMG, 2005 E55 Wagon
Guy's dad has him thinking it burned up a valve due to the "dollar bill test" where you hold a dollar up to the tail pipe and if it ever tries to suck in the dollar, you have a burnt valve.
But wouldn't clogged exhaust have similar results?
But wouldn't clogged exhaust have similar results?
03-23-2016, 08:40 AM
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99 C43 AMG, 01 ML55 AMG, 05 C55 AMG, 02 CLK 55 AMG, 99 Slk 230, 03 SLK 230, 02 C230k, 98 C230
You can always give him your engine when you pull it for the e55 motor arriving.
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03-23-2016, 10:25 AM
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1999 C43 AMG, 2005 E55 Wagon
My 4.3 is 300k miles, runs real strong, but needs a timing chain. How much should I ask?
03-23-2016, 10:59 AM
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99 C43 AMG, 01 ML55 AMG, 05 C55 AMG, 02 CLK 55 AMG, 99 Slk 230, 03 SLK 230, 02 C230k, 98 C230
or this one for $750 with 103k miles http://www.ebay.com/itm/98-99-00-MERCEDES-C43-ENGINE-202-TYPE-C43/111513357413?_trksid=p2047675.c100005.m1851&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%26asc%3D36188%26meid%3D850387e7afeb4865ab0e6ecf6778cc0f%26pid%3D100005%26rk%3D1%26rkt%3D6%26sd%3D141912110773
For yours i would say half that cost since he doesn't have to factor in shipping or anything.
03-30-2016, 02:19 PM
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1999 C43 AMG, 2005 E55 Wagon
well he did a compression test and cylinder number 8 is showing 165 PSI, so I guess that eliminates a burnt valve. the range across all 8 was no more than 10psi, which is normal.
so really all that's left at all is clogged cats, engine harness, or ECU
so really all that's left at all is clogged cats, engine harness, or ECU
