2007 Mazda CX7 6 cyl Four Wheel Drive Automatic 6200 miles
My vehicle had black smoke coming out of exhaust (upon startup) in both the winters of 08/09 and 09/10. The colder the weather got, or the longer the car sat idle, the worse it was.
The first winter season Mazda dealer did:
- system diagnosis. Fault code P0300 random misfire detected. May have been a temporary cyclinder misfire on cold start. No black smoke seen. Clear fault code and road test.
- replace fuel pump assembly according to bulletin 08/09. For random misfiring and rich running on cold start.
lamp was on. When cold starting, black smoke from exhaust comes out. Once vehicle warms up vehicle ok. Only when cold weather started that this problem occurs. Was in last winter for same reasom
-P0301 - cylinder 4 misfire
- replace cylinder 4 coil
- road test
don't have printout, but they say they changed Turbo
After the turbo was changed I called them 3 times to let them know that the smoke still emitted on cold days, although it wasn't nearly as bad.
Was told to run car for a while to get rid of any leftover residue, than told it is normal to see a little black smoke due to mixture of oils, and that black smoke isn't nearly as bad as before, so car is ok to drive
Called again in April to say smoke seen on 2 cold days.
Was told that the weather tempature has nothing to do with the smoke, and that since the turbo was replaced, there is no longer a problem
Now white smoke is coming out, with a very pugnant smell. They are looking at that next week.
My warranty runs out in two weeks, so I asked what would happen if the black smoke appears next winter.
I got no reply. Tell me --- If a problem arises while under warranty, and signs indicate that the problem wasn't resolved while under warranty, then shouldn't the dealer be responsible for fixing the problem if it resurfaces?