306 XND misfire and blue smoke

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tiger63
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306 XND misfire and blue smoke

Post by tiger63 »

My car starts and idles fine but on about quarter acceleration and above the engine seems to hold back and revs fluctuate even on steady throttle. When this happens the exhaust has a bluish colour. Any suggestions gratefully accepted
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fastandfurryous
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Post by fastandfurryous »

could be:

blocked fuel filter,
seriously blocked air filter,
slipped timing,
restricted exhaust,
air in fuel (although this is unlikely if the engine starts fine)

Did the problem come on suddenly, or progressvely? do you service the car yourself?

More info please.
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tiger63
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Post by tiger63 »

i bought the car about 5 months ago , when i drove the car home it was holding back then clearing but no smoke was evident at time. Now ive got round to getting it ready for the road the blue smoke has started. ive just changed the fuel filter and added some redex diesel injector cleaner. it almost feels like an injector is dodgy as when holding throttle steady you can feel the engine jumping on and off a cylinder i think
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fastandfurryous
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Post by fastandfurryous »

This sounds like the fuel tank vent is blocked and hence creating a vacuum in the fuel tank.

Is there a big suction noise when you remove the filler cap? and does the engine run properly if you leave the cap loose?

and have you checked the air filter?
Will the engine rev to the limiter not under load?[/quote]
Last edited by fastandfurryous on 13 Apr 2006, 14:52, edited 2 times in total.
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AndersDK
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Post by AndersDK »

Have a friend follow you on a road test drive to look at the smoke under various conditions. Do NOT drive on the road while your attention is kept on the rear view mirror :evil:

The plot is to establish a more certain diganose on the smoke colour.

Grey smoke is normal smoke from a heavy loaded (accelerating) engine.
Black smoke is from an over-rich fuelled engine.
Blue smoke is engine oil being combusted.
White smoke with a blue tint is unburnt diesel fuel.
Pure white smoke is either coolant or engine oil from turbo hot side seal.

Next catch some condensation from the exhaust in a rag and diagnose by the smell what it is.
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tiger63
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Post by tiger63 »

went out and had another look at it just now, the smoke is definately blue and as when i took out the dipstick i detected crank pressure, this would lead me to think along the lines of head gasket. would these symptons be typical of a blown head gasket. also noticed engine is hunting a bit, if this were a petrol i would have been looking for an air intake leak
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fastandfurryous
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Post by fastandfurryous »

I wrote:Is there a big suction noise when you remove the filler cap? and does the engine run properly if you leave the cap loose?

and have you checked the air filter?
Will the engine rev to the limiter not under load?
:?:
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tiger63
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Post by tiger63 »

no vacum at tank, ive just put in a new air filter and no its not revving freely even with no load. it seems to be holding back and when it does thats when i get the blue smoke
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fastandfurryous
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Post by fastandfurryous »

In which case, I'm beginning to think the injection timing may be badly out, as a result of a slipped timing belt. That would account for the lack of power, lack of revving, and would also create some very odd colour smoke in the exhaust.

Is it in need of a belt anyway? would be worth checking.
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tiger63
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Post by tiger63 »

will take off timing covers tonight and pin engine and pump to check timing
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Post by tiger63 »

no joy, i locked flywheel with an 8mm rod, then fitted the m8 bolt to cam and the two m8 bolts to pump so would appear the timing is fine
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fastandfurryous
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Post by fastandfurryous »

Err.... Err.....

Running out of options now.

Blocked exhaust.... maybe. Not very likely, but possible.

I still think it's a fuelling fault somewhere. Try this:

Run the engine. Rev the engine while pumping the fuel primer like mad. Will it rev up now?

If so, then it's a damaged vane transfer pump (the LP part of the injection pump) I had this happen on my 405 a while ago. If this is the problem, you need a replacement (breakers yard) injection pump.
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tiger63
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Post by tiger63 »

am more convinced now its cylinder head or gasket as when i removed the black air box the car revved better. but the thing that makes me think gasket or head when i place my hand over the air intakes at back of engine 1 and 4 plenty of suction but 2 and 3 hardly any so leads me to think gasket between cylinders 2 and 3 what do you think
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AndersDK
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Post by AndersDK »

Would fit the bill on the blue smoke I guess ... :?
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tiger63
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Post by tiger63 »

Will remove cylinder head tomorrow for inspection with steel rule, hopefully just gasket, fingers crossed :?
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