Starts then Dies

[UndrGrndPrdcts]

My dads 91 will start up and run for a few seconds then die. Then it turns over and he keeps cranking it and pumping it then finally it starts with lots of smoke and it revs up then settles back down. Whats wrong? Is it losing pressure in the lines or what? And from where? We can't see any moisture from anywhere. I have a feeling its losing fuel pressure to the pump but we cant figure out from where.

 

[haligen]

Checked the return lines? Mine acted the same way but I just did my return lines and fuel filter head check valve and its all gravy now.

 

[Compu Doc]

How cold is it outside when this happens?

 

[UndrGrndPrdcts]

Lines all seem dry. I told him to replace all the fuel lines. We have one of the valves on the filter head capped off but i think there's two?

 

[UndrGrndPrdcts]

Various temperatures.

 

[haligen]

The barbed check valve that the return line hooks to on mine was stuck open. Pulled it off and could see straight through it.

 

[UndrGrndPrdcts]

Will have to check that.

 

[icanfixall]

Tell your Dad nicely that pumping the throttle will not do anything to start the diesel. Thats a gasser trick and it usually works for them.... We don't have an acellerater pump like a carb does. Now holding the throttle wide open will push more fuel thru the pump and that MAY help start a problem engine. How old is the fuel system. The injection pump, the injecters, the return lines and the mechanical lift pump. Also these trucks usually have a broken off suction in the fuel tanks. We run out of fuel with a 1/4 tank left that we can't suck out... Do you fill up a tank with it only needing 12 gallons... Thats whats going on then.. Hopefully you can answer these questions.

 

[UndrGrndPrdcts]

He has run it below a quarter tank and not had problems with running out or anything so I'm not sure about that. It supposedly only has 64k on it and it looks it. The engine is all gray yet with hardly any dirt or grime. Only things that may need replaced in my opinion are supply and return fuel lines (PA rust).