Starts right up , but only runs for 3 seconds. . . crank-it for 45 sec. to start

Thanks, but why would it run just fine after it does start. . . . And it DOES ALWAYS START right up hot or on a cold engine. But of course as I said only runs about 3 seconds (on a cold start). And then just fine after the "long-crank" ? And always a quick start for the rest of the day if the time-factor is less that five or six hours. (?) --- I think the blue smoke is because after cranking for 45 seconds, all that extra fuel is now in the exhaust manifold (?) And lets just say oil was leaking down to the cylinders (again) WHY WOULD IT START RIGHT UP (If for only 3 seconds) IT DOES FIRE EASILY. It would seem to me if all that oil was sitting there, 'it' wouldn't want to "fire" ! (?) {and I don't show lost of oil on the 'dip-stick' yet} ______________ Here is the advice I have got so far, do you agree ? And my book doesn't show the "CRANK & CAM" sensors ? If you do agree that it could be the sensors (I don't agree) where are they and can I get to them easily (?) (approx cost $) Don't want to be swapping out expensive parts just for the HE*L OF IT ? ! {to me this sounds like advice for a gas engine not my diesel ?} _ HERE'S THE ADVICE: => "Swap out the crank and cam sensors" ___ "Faults with hall effect sensors are difficult to diagnose without an oscilloscope to capture the output. Timing is everything. The Engine/power control unit (ECU) takes signals from the crank sensor (CPS) to know where the piston is with respect to top dead centre. The cam sensor also tells the ECU when the piston is at TDC but it also tells the ECU whether the piston is on TDC for the power stroke or TDC for the fresh injection of fuel. If the ECU loses track of either the crank or cam sensors it has no real chance of maintaining the correct timing of fuel injection. Badly timed injection of fuel equates to an engine that is hard to start and prone to stall. If the timing is just slightly adrift the injection cycle might be short in which case the fuel mix will be lean. Lean burn is sustainable in a warm engine (you say yours starts easily when warm..) but makes it difficult for a cold engine to start and keep running (you said that it starts but dies quickly and is then difficult to get going....). From what you said I diagnosed that it was more than likely that the injection timing was off and since the cam and crank sensors are key to this but are a pain to confirm as being at fault but are also not too expensive or difficult to swap out that this would be a good place to start. If the problem persists at least you will know for sure that it is not the cam or crank sensors. Hope that helps give some back ground to my thoughts to what was, i admit, a very short solution. . ." __________________| __________________| Dandd, what 'da-ya think ? thanks again.~ shade-tree