75ZT Community

This morning whilst defrosting the ZTT with the throttle held at 1500 revs I noticed the car was smoking very badly from the exhaust and smelling very strongly of unburnt derv along with a noticable misfire which is audiable from the exhaust too. The smoke is bright blue and there is lots of it. On tickover it goes almost straight away, no smoke whilst driving.
The snow behind was coated rather thickly in an Amber coloured oily layer, suspiciously like neat deisel.
It always smokes like this when held on the throttle when cold, once it's warmed up it doesn't seem to smoke, but the exhaust always smells very strongly of diesel.
The car is drinkng derv too, like 1/8 of a tank for 15 miles running about.
It's done 140k miles... So the question is, what's wrong with it? Injectors, MAF (Mass Air Flow Sensor) or something else?

hi worth remebering all engines smoke when cold however this sounds a bit over the top disconect the maf sensor see if makes any difference but by the sounds off it with the increase in fuel compsumption it is overfueling which could point to a injector problem i assume you have done all the obvious things ie cleaned the egr valve checked the pcv and done your plenums?

I cleaned the PCV (Positive Crankcase Ventilation Valve) last year sometime, it's still running the original style one though.
I'm going to disconnect the MAF today and see what's what with that.
EGR (Exhaust Gas Recirculation Valve) was disconnected years ago so should be fine... I will check it if the first two things don't make any difference.

Mine was doing this a little while back.

Have you changed the oil lately, as mine had been slightly over-filled.

However, that didn't totally solve the problem, just improved the length of time it was smoky for.

The problem finally went away on mine when I changed the air filter for a Mahle one. They are fitted OE in Germany and are excellent quality paper filters.

This problem has many possible causes apprently. I would rule the cheaper ones out first and work from there.

I had changed the PCV on mine, fitted an EGR bypass and run through a couple of bottles of injector cleaner without success.

Well, its still doing it with the MAF unplugged, and smokes slightly when warm too.
Its too bloody cold to be changing PCV valves here
Im leaning towards tired injectors....
Does anyone round Nottingham have a testbook they could plug up to see whats happening in exchange for beer tokens, before I chop it in for a petrol version?

do you run a synergy ?

I've got the TU3 I think its called and the seperate MAFAM for the Pierburg MAF. My new style PCV has arrived this weekend so I will be fitting it and see how that helps...
I have noticed the problem seems to have vanished now the weather has warmed up here... Could this be a coincidence?

it looks like you'll get another chance to try it in the cold at the weekend Andy.
Is it still drinking derv?

Not too sure... Its the wifes car now and she is off work expecting our second child so its not really being used at all...
It did seem to use less as the temps went up above freeing though.
New PCV is still on my list of things to swap out...

New PCV (the uprated one) fitted and seeing how things go with it in..
The inside on the old one where the spring and diaphragm was is very oily, it was running out... Is this usual?

No!
They get like that when they need replacing (normally sooner) around 30K miles is normal and the "new|" type also needs replacing but not so often,
I haven't got the mileage to hand but will come back with it.
If left the pressure can build up blow back through engine oil dipstick tube and can if not sorted at all technically blow your engine up.

Well, that seems to have done the trick. Car runs fine, no smoke, no hesitating or coughing... All is well again

Thanks for reporting back. Always helpful!

As Duncan says thanks for reporting back.
The new "lifetime" PCV needs replacing around every 85,000 Miles.