1974 jaguar xj12 smoke problem
 

Hello again
Does anyone know if the smoke problem has to do with the air pump (smog air pump)?

Fortunately you have only 6 posts so it was easy to go back and find out what, exactly, your smoke problem is :-)


The air injection pump provides fresh air into the exhaust ports of the cylinder head. I can't see any way that it could cause a smoking or mixture control problem.

Cheers
DD

reply
 

Hello!
Thank you for the answer.
I bought this beautiful car two years ago from U.S.
From the begining the car was overheated.
I changed both thermostats , water pump ,all the water hoses, i rebuilt the carbs, i cleaned the radiator and many other things.
when i got the car from the engineer the car was running very well,the temperature was very well but the car started to smoke from the left side exchaust and smelled gas.
When i got back the car to the engineer he told me that water may pass into the engine.And he showed me in that exchaust that with the gas is coming out drops of water.
Is it possible ?
The smoke is black and it smells a lot of gas.

thank you
alex-john

It IS possible for engine coolant to enter the combustion chambers and exit the exhaust, yes. This could be from a leaking head gasket, cracked cylinder head, or defect of that nature

However, water is also a natural byproduct of internal combustion so water vapors can accumulate in the exhaust, condense into liquid, and exit the pipes as actual water droplets. As a rule, though, this would disipate after the engine (and exhaust pipes) have thoroughly warmed up.

I would find a carburetor specialist to help with the black smoke problem

Cheers
DD

reply
 

I forgot to mention that we occasionaly add coolant .
We don't see any leak.
Is it possible for this to happened after service ? cause we didn't add coolant before.The oil tap of the engine is clean without white foam.
What we should do about that ?

thank you