volvo penta AQD21A problem

[krv]

hope somebody out there can help!! i am not a mechanic but i will try and explain the problem. when cold it takes ages to start with plumes of smoke as though one cylinder runs then another,then another then all of a sudden all four kick in then it runs perfect with no smoke and very responsive, this sometimes takes up to 5-10 mins and lots of smoke and cutting out inbetween!!once run its ok if not left to long.
if we retard the injection timing slightly it starts from cold straight away but runs bad, slugish and non responsive on the throttle,with not as much smoke but smokes constantly, we cant find anything inbetween!. we have had the fuel pump checked,injectors,lift pump,fuel lines,compression, and assume fuel is ok because other engine is fine.
any advice would be gratefully received
regards.

 

[alan006]

When you checked the compression of the engine, did you compare it to the other engine or did you just compare each cylinder with each other?
I'm not an expert on this but I have read that where an engine is worn it can take much longer to start than normal. As the engine is cranked over unburnt fuel will work its way down the cylinder walls and help make a seal with the piston rings. The engine will smoke while all this is going on and as it starts will take a short time to stop smoking.Once the engine is running it will reach its warmer operating temperature thus causing the piston rings to expand and solve the compression problem.
If the compression readings on the poor engine are the same as on the good engine this possibility could be eliminated.
As I say this is not really my field but I have read about this, so good luck.

 

[[448]]

You don't mention checking the HEATER plugs. This engine is based on the old (1970's) Peugeot 2.1 engine, if I remember correctly, the plugs are NOT the same as more modern ones, and may be difficult to source.
Dave