Hi Derek,
What colour is the smoke?
If it is standard diesel black smoke it will most likely be down to something
on the fuel system side of things.
Things to check are:
Fuel filter - has it been changed recently - if not change it just to eliminate
it from the enquiries.
Air filter - as above.
Injectors - how many miles has the engine done? If it has done a fair few you
might need to get the injectors serviced. This can get expensive - for my 80
it can be between ?11-22 per injector if I take them into a local specialist,
obviously more if you have to get them to take them out. If they just have to
strip them down, swap seals and clean them then it will be the lower price - if
any of the components are worn then they will need to be replaced which will
raise the price to the higher limits.
As a cheap alternative go to you local motor factors and get some injector
cleaner to put through with your next tank of fuel - that might make some
difference.
If you are still getting a lot of smoke then you might need to consider getting
the injectors out and serviced.
Another thing to check on higher mileage engines are the valve clearances -I'm
not sure what type you have in the Colorado, but if you are going to get the
injectors taken out (or are going to do them yourself -I would spend the time
when the vehicle is off the road checking and adjusting the valve clearances.
I hope that helps.
--
Regards,
Julian Voelcker
Mobile: 07971 540362
Skype: julianvoelcker
Cirencester, United Kingdom
1994 HDJ80, 2.5" OME Lift