My 8 valve punto has 151000 miles done.
It has been misfiring lately,changed all the electrical items,and checked the injectors,all ok.
Could it be the compression is low,the spark plugs are all black and sooty.
would this indicate poor compression.
am now thinking about scrapping the car as if the engine is worn its not worth fixing.
tony

TONY55S said:

My 8 valve punto has 151000 miles done.
It has been misfiring lately,changed all the electrical items,and checked the injectors,all ok.
Could it be the compression is low,the spark plugs are all black and sooty.
would this indicate poor compression.
am now thinking about scrapping the car as if the engine is worn its not worth fixing.
tony

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If its dry black soot rather than wet black oil then it seems there is too much petrol or insufficient air. I dont think it is anything to do with the compression.

Could be a throttle problem or blocked filter maybe. But you must have run it with the filter off already.


What about the oxygen sensors? They are good for about 160,000 miles so they are near the end of their life. If they fail then the car will run with too much petrol as if it is a cold start and will remain like that even when the car has warmed up. You would get an OBDII code and I am assuming also the check engine light.

It is possible for the injectors to leak constantly instead of going on and off correctly but since all plugs are black that is not sounding like it is likely for all injectors

All four are dry and black/sooty?..how old are the plugs/ignition packs and leads?..