Mazda 323 (1998 - 2003) - 2002 2.0TD Blue and black exhaust smoke

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Thu 28 Aug 2008 20:02
2002 2.0TD Blue and black exhaust smoke - Galad
My Mazda 323TD (90k miles) has started running rough recently hestitating and surging at low speeds. Today I felt a distinct lack of power pulling away from stop. Runs okay at higher speeds. When revving at c2k when staionary there is first blue smoke then black from the exhaust and the engine stutters then runs okay above 3k revs. Engine has been regularly serviced. Still on original exhaust - could this be on its way out? Any ideas most appreciated.

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Thu 28 Aug 2008 20:33
2002 2.0TD Blue and black exhaust smoke - Screwloose
Galad

Surging can often be air in the diesel; can you fit a bit of clear tube in the leak-off and see if there's any bubbles flowing back?
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Thu 28 Aug 2008 20:50
2002 2.0TD Blue and black exhaust smoke - Galad
Screloose, would that also cause the excessive smoke at lower revs? It's possible that the fuel filter wasn't fitted properly by the last garage I used. I'll get it checked
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Thu 28 Aug 2008 21:44
2002 2.0TD Blue and black exhaust smoke - Screwloose

Yes; if there's air present the injectors won't atomize properly.
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Thu 28 Aug 2008 22:27
2002 2.0TD Blue and black exhaust smoke - Galad
Thanks again. I'll follow that up asap and let you know.

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Fri 29 Aug 2008 19:47
2002 2.0TD Blue and black exhaust smoke - Galad
Screwloose
Got the Mazda dealer to change the fuel filter although he was sceptical when I described the symptoms. Mechanic changed the tank filter at the same time just to be sure and remarked that there was some dirt in the engine bay filter and something about the O ring but said that otherwise the car was fine. Out on the road however the surging and hesitation are still very noticeable at low speed, always around 2000 revs and there's a cough when changing down to accelerate. Took it for an Italian tune-up on the Motorway but no difference. It runs fine at 60+ in top gear What seems to have changed is the absence of the grey and black smoke when revving the car stationary which happened to me yesterday.

Is there any clue as to what else it might be such as sticking EGR valve or injectors? Can't imagine it's dirty fuel because the symptoms have been noticeable since the fuel filter was changed by an independent mechanic 4 months ago. My next step is to ask the dealer to do a full diagnostic.

Cheers
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Mon 1 Sep 2008 18:01
2002 2.0TD Blue and black exhaust smoke - Galad
Turned out the problem was down to a dirty air filter element. Lifted out the old filter by chance and although it was only replaced in March (7k miles ago) it had collected a lot of crud and dust. Pity the mechanic in the dealership didn't think of that before me. Could have saved me £60 replacing a fuel filter unnecessarily.
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