Hello everyone i have a 1995 cheyenny 3500 6.5 turbo disel truck. im just wondering if i should change the lift pump first b4 going to screw around with the injactors pump? and if i do change the lift pump my question is do i have to bleed the disel from any air pockets in the lines?

 

On the 6.5 if you open the fuel feed system for any reason you have to bleed, but all you have to do is follow the owner's manual instructions and bleeding is nearly automatic and all done from above with a cool one in the other hand.

Because of the inherently excessive clearance in the OEM rotary injection pump used by GM, you should contact a pump shop and get one with the modified aftermarket ceramic pistons and hardened housing before you tweak anything. If you do not, you will stand yourself on the first day when the temperature goes above 80 degrees F when the fuel thins and will no longer build sufficient pressure to pop the injectors.

Do not worry about the fuel supply pump, what GM calls the lift/transfer pump, if it will prime and bleed without any problem it is good. If there is a priming or bleeding difficulty, then you need to replace it at that time. GM actually got that one right and it seldom fails!