QuestionQUESTION: At cruising speeds(30-40ish MPH)car develops judder and blue smoke, worse when going downhill, no throttle. This gets progressively worse until you need to stop and rev engine, which will after a short time pick up, smoke will clear and car will drive perfectly, sometimes for as much as 35-40 mls driving short 4 or 5 ml trips.
All regular checks have been performed at garage.Nothing shows up,we are totally baffled.
Have also checked silly things like oil level,updated hose clips to turbo and cold start position.....Yours very hopefully, Malcolm.
ANSWER: It is BLUE smoke?, EG burning oil?
does it ONLY start playing up during no-load/engine braking, never at other times?
Have you had a compression test done, this would be useful.
Also do you know the condition of the valves/valve stem seals.
And has this engine ever snapped it's cambelt and been repaired.
(What are these checks that have been performed so far, so I know where you're upto)
---------- FOLLOW-UP ----------
QUESTION: Hi Christian,
Smoke is whitish blue, does'nt seem to be oil as it does not use any as with water.Acquired car at 86000, now just over 93 but have known vehicle from 1yr old when bought by previous owner, who to say the least, twitched a bit, so everything was done spot on or before it was due at a Ford main dealership.
Understand that compression test etc was carried out not long before my son got the car, all AOK .Can't be 100% on valve stems,but assume something should have shown at this point.The car has never snapped cambelt,in fact as long as we've known it has had no problems other than fair wear and tear.
The only other time that the symptoms appeared was once,fleetingly from cold start, but this cleared in 30 seconds or so.
I am unsure exactly the checks perfomed( lack of technical knowledge)but can only say that my mechanic is very highly rated locally but baffled by this one.Seems to be looking at air getting into 1 or more injectors as it always seems to happen after a long downhill stretch.Problem being that as it is so sporadic, the car,even after more than 10mls of test driving,just won't perform at the garage.
Hope this is a little more help,sorry i'm vague on the technicalities.
All the very best ..........Malcolm
Answernot vague by any standard.
but a damn hard fault.
After lots of thought I come up with
"something sticking that is exposed to the vacuum when you are under engine braking..."
oof...
Positive Crankcase Ventilation valve / EGR valve sticking - can cause the turbo to leak oil which can foul the sensor in the exhaust:
that would give white and blue smoke and juddering.
that Or some turbo fault.
that's about all I can think of, if you get any more info on the problem let me know.
Pretty sure it's a sticking valve, EGR or PCV (dunno if it has a PCV valve or not)
Run it by your mechanic.
