Excessive crank to start
 

Having trouble with my 96 6.5. I have to crank for a long time before it will start. I have changed the glow plugs checked the glow plug controller all ok. Both batteries are new. Fuel and air filter recent. Lift pump ok .There is a small puff of white smoke when it starts. After started runs great not problems. Are there any one way check valves that could be letting fuel bleed back to the tank or could this be caused by the pmd. I replaced it last year but it was a cheap one off of eBay. Any ideas would be great. Thanks.

only thing left is pump timing and injection pump failure. my truck was extremely hard to start and it ended up being the injection pump was dying. unplug the cts sensor on the thermostat housing which will advance the timing all the way and see how it starts

I tried that no change. I seems to start fine hot or cold if it has just been running. But let it sit for 20 min and it is hard to start again like it is getting air in somewhere

run clear fuel line on return from IP see if got air in it

i forgot also its possible your injectors are getting old and leaking fuel into cylinders when not running then when you try to start the truck it has to start with unatomized fuel on the pistons which explains the white smoke. also try what crazy said and run the clear line

where is the easiest spot to put in a clear line?

at the injector pump it short hose that goes to a T that goes to each side of the head to injector

That fitting on the top of the IP is a check valve. It allows fuel to flow out into the return system, but should not allow any flow into the pump. If it goes bad, you lose prime and have to suck fuel through the lines (cranking) until it gets fuel to the IP. A 9/16 wrench will take that off. Remove it and make sure you can only blow air one way ("out").

I removed and checked that valve seems to be ok. I installed a piece of clear line on to the return side of the ip. there are no air bubbles being forced out when it starts but when it sits over night there is large bubble that forms in the line.

other thing that can be gaving you hard starting is the Optical Sensor and do still have the Optical Sensor Filter Harness if you do remover it see if start easyer