C220 Black Smoke (W203)

terrywogan

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Jul 6, 2017
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C220
I have a problem with my 2005 C220 which results in a puff of black smoke on initial acceleration. Once up to speed there is no/very little smoke.

I've had the car for 6 months. The person before me had a remap (which I know can cause overfueling thus black smoke) but I hadn't noticed it until recently. Here's what I've tried/checked so far:

  1. New air filter
  2. Checked for any air leaks in intake/turbo hoses/intercooler
  3. Run Redex diesel in a tank of fuel
  4. I don't use supermarket fuel
  5. Checked for visible and audible sounds of injector leak - nothing found
  6. Taken the car on a good run on the motorway - no change

I presume there is an overfuel or one of the injectors isn't operating correctly. Could anyone give me any advice on where to look next before I start getting into the expensive world of replacing injectors?

TIA.
 

bob6600

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AUDI S8 V10, S210 E320 CDI (R.I.P.)
STAR can check injected quantities or you could do a leak off test. This can be done with home made plastic bottles and tubes.

The EGR could be clogged, may need cleaning out
 
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terrywogan

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Jul 6, 2017
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C220
STAR can check injected quantities or you could do a leak off test. This can be done with home made plastic bottles and tubes.

The EGR could be clogged, may need cleaning out
Thanks, I guess easiest for me to check will be the EGR valve. Is this the section with two torx head bolts near to the bulkhead? Undo, remove and clean out with a brush and petrol?
 

bob6600

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AUDI S8 V10, S210 E320 CDI (R.I.P.)
I'm not sure where it is on your engine but I'm sure someone will come along and point it out
 
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terrywogan

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Jul 6, 2017
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C220
I wanted to post a reply for anyone who may be experiencing this problem.

I didn't have a STAR dealer nearby so took it to my local VAG specialist. There just happened to be a guy there who used to work on Mercs so he had a good look over the car. Removed the EGR valve (remarked that it was in very good order for the mileage) and also did an injector leak test which was positive.

After giving the car a good look over he said it was simply the remap that was making the car puff on acceleration. His advice was not to worry and to make sure I give the car a good "blast' every now-and-then. He said those diesels are built for motorway driving not poodling around town.

£96 well spent. If anyone is interested the garage is Coggeshall Auto Repairs in Essex. I dealt with a guy called Clint.
 

KeithJG

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Nov 5, 2014
Messages
598
Location
Dover, Kent
Car
Vauxhall Tourer
Every engine gives a puff of black smoke on initial acceleration.......it is the continued black smoke which is bad.

If you are still concerned about it or the amount it puffs from a standstill them put some 2T oil in a ratio 1-1200 and the engine will run smoother and quieter due to the better burn and virtually no smoke at first throttle.

If you think this move is rubbish try it once and then see if you continue with it......
 

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