Archived 96 Loosing Prime

[JSTC]

96 12V Will start up and run for about 10 seconds then die. Hard to get restarted. When running for a minute it stays running. I think it is loosing prime. Where should I check and how? John

 

[bmoeller]

The rubber fuel lines are prone to cracking, and letting in air. Won't always leak fuel, either. Mine didn't. That is where I would start. They aren't real easy to get at, but is doable.

 

[Joe G.]

http://dieselram.com/ubb/ultimatebb.php?ubb=get_topic;f=45;t=000007

 

[JSTC]

Are you talking about the two rubber lines located near back of engine or the lines off the lift pump? John

 

[Joe G.]

The lines off the lift pump are steel.

 

[bmoeller]

two rubber lines located near back of engine

Yes, and the short curved one between the lift pump and fuel heater.



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[SMalafy]

Your fuel heater pre filter could be plugged too. I would think if you were sucking air it would not run very good for 1 minute. There is also the 2 rubberlines behind the fuel filter too.

 

[McLaughlin]

You mentioned that once it dies it is hard to restart. Have you tried hand priming it before the restart? If it starts right away then it may be a indicaton where you are loosing the prime. Our 96 wouldn't start if parked on a hill at night unless hand primed and a bad lift pump turned out to be the cause (it was also leaking diesel fuel at the hand prime button).



Have you checked for water at the fuel filter? I've seen that cause a similar problem (truck would start run for just a bit and then die) but it usually was worse when accelerating or stopping.

 

[JSTC]

I replaced the 5/16 & 3/8 fuel lines & the "L" shaped rubber hose on the lift pump. It started & ran fine this morning. I'm not totally convinced that was the problem since the rubbber didn't look that bad. . I'll give it more time & let you know. Thanks for all the advice...

 

[RHARVEY]

I had the lift pump start loosing prime. But it was crazy how it would do it. If I parked the truck nose up hill it would loose prime but if I parked it nose down hill... didnt give a bit of problem. I called Cummins and this was the first thing he said... the lift pump is the problem. I had just replaced the lines so I knew it wasnt that. .



Rick

 

[JSTC]

Its been running fine untill this weekend. Back to the same problem PLUS it will not idle unless my foot is on the pedal. Do you think it is the lift pump or injection pump?