C220 cdi w202 smoking / sluggish / top end tapping

Dray

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99 T W202 C220 cdi sport auto
I have scoured the forum for suggestions but haven't found a lot for W202 specifics, so am hoping people might have some advice.

I picked the car up, fairly cheap, a few weeks ago. I could tell it wasn't perfect but the money was right, it had good history and only 120,000 miles, so I went for it.

So far:
-have changed the thermostat- now sits a 80/85 degrees rather than 50-60.

-Re-seated injector number 4, which was leaking- Black Death had already begun.

- run some Wyn's formula gold through a tank of diesel.

-changed a very grubby looking fuel filter and put in a new air filter.

Car is running a lot better already. Starts perfectly. However, still has the following symptoms, some of which might just be characteristics of the car, so am fully prepared to be told that.

- tapping/ticking noise from top end somewhere- particularly noticeable when cold, does virtually disappear when fully warmed-up.

-sluggish in first gear, at least until 2000 rpm. Worse when cold, although not great when warm. As soon as it reaches 2000, it flies along and happily revs up to 4500 rpm if you keep your foot down.

- along with the sluggishness is a air bit of black smoke, not horrific, but looks like a lot in the headlights of the car behind you. Smoke remains high while accelerating hard. Although steady acceleration with changes at 2000/ 2500 rpm doesn't really produce much, as there is very little smoke at tick over, after the initial brief puff.

- turbo fairly noisy- aware of it spooling up to speed and spinning down. Are they fairly noisy anyway? Also drive a jtd Alfa so that's all I can compare to- it is a lot younger and fresher in fairness.

Am reasonably competent and engine seems very workable (again compared to Alfa) so wondered if anybody could give me a idea of where to start, in terms of an order of components to clean/check/get tested.

My initial thought is to get injectors tested, although also know that could see me spending four figures. And/or EGR valve- dismantle and clean. Checking pipe work between turbo / intercooler / EGR for leaks as could explain turbo noises?

Any corrections or additions would be gratefully received. My local Indy has a reasonable reputation but is expensive in my opinion. And I'd rather work through sorting it out myself if possible, even if I takes me a few weeks.

Thanks very much.
 
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Dray

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Just to clarify the 'sluggish' thing, I mean a real reluctance to rev. We live on a moderate hill and in the morning, when she's cold, you virtually need full throttle to pull off (up hill) and she does so in a VERY leisurely way. Again, until revs have picked up to 2000+. When she's warm, she' not that bad, unless the car is full.
 

rolfy

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Hi Dray

I'm no expert but had the sluggish pull-away problem similar to yours. Turned out to be a worn injector (the poor spray pattern caused a slight mis-fire at low fuel loads) so seems like you're on the right track getting them checked . Do you get any judder when manouvering at low speeds, esp. when cold?

Clueless on Turbos, I'm afraid, but could the smokiness be MAF related?
 
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Dray

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Thanks, Rolfy. No, no judder at low engine speeds, but the idea of a failing injector, or two, seems quite plausible. Just trying to rule out everything else first. Interestingly, unplugged MAF just to try it and it runs the same, if not better without it!?
 

denchen

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I know it was a different motor but my old c270 had the same sort of problem and the egr was so clogged up I was surprised the motor could breath
 
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Dray

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EGR is on the list for this weekend. Although not totally sure how to test if it's working, with the vacuum etc etc. Could anyone advise, please?
 

denchen

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Again Dray I know we are talking of different engines but on mine there is a simple wire type clip that is easy to remove, then the pipe from the turbo is easily pulled away from the front of the egr. Its easy then to see if the egr is gunged up. I cleaned mine up without any more dismantling by digging out the gunge and spraying an electrical cleaner at what was left. The purist will say the whole thing should be removed but that is all I did and mine went much better afterwards. To have a look on mine was a two minute job annd I. Got the clip off with my thumb nail. Good luck.
 
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Dray

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Thanks for the response, Denchen. Don't think our engines can be that different. EGR seems easy to access and even take off. I was wondering more about how to test its mechanical function, because it's vacuum controlled isn't it? Anyway, sure I will become obvious when I take it apart. Cheers again.
 

denchen

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I understand one symptom of a dodgy egr is bad starting when hot. I know a guy had this problem on a ford tranny, and he adds a drop of two stroke oil to the diesel. He swears its cured the problem. I dodn`t know but thats what he says.
 

turbopete

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try the egr mod thats detailed on the forums here, AND clean it out to ensure it is properly closed. also you could try disconnecting the MAF and see if it makes any difference.

as your car is an auto, has the fluid been changed recently? this may help with the setting off problem and also if the gearbox is in W mode (sometimes the plunger sticks in w mode all the time even though the switch appears to be in S) the car will set off in 2nd gear unless you really floor it to make it kick down to first.
 
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Dray

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Thanks for your suggestions. I might try the mod, if I can work out how to do it. MAF is currently unplugged and if anything, car is running better. Will clean EGR this weekend and then see where we are. The tapping noise seems to be be continuing even when warm now, so an ill functioning injector or two seems fairly probable. That said, having run a tank full of wyns gold formula through her, there seems to be a lot less smoke and when fully warmed-up, very little unless flat-out.
 
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Dray

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update

Ok, so I cleaned the EGR which was pretty dirty and totally stuck in the closed position. I cleaned-up the egr/inlet manifold and put it back together. As the egr is broken, and never open, should I disconnect the vacuum pipe, or will this upset the ECU somehow?

Car now running well at when it reaches full temperature, but struggling a bit when cold. At first start on cold mornings, initial acceleration is VERY sluggish, to the point where you need to almost 'floor' the accelerator. This is accompanied by a lot of smoke. However, as I said, when fully warm, responds very well, if a bit smokey still. Other than the injectors, is there anything else I should be looking at? Is there any sort of cold start valve? Or maybe a coolant temp sensor, other than the one in the thermostat which feeds the temp guage?

Thanks for any ideas you have.
 

PieterH

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I cleaned my cars EGR yesterday. I used Wynn's Carb cleaner and a rag and the entire job took less than 10 minutes. There was not a lot of carbon on the inner shaft on the EGR and the carb cleaner dissolved it within seconds. Still need to clean the lower part where the sensor is but I will do so when I change the engine oil. Car has 150 000km on it and I maintained it since 68000km.
 

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