Site Navigation

Your Account

Choose Language

loseing prime on a 99 3406 cat

Lately about 4times already when I park my truck over the weekend I dont crank it until sunday, a couple of hours before I have to leave out, just to make sure that it cranks alright. But lately when it sets and I go to crank it on sunday it will run for a few minuntes and then shut off. The first time I checked the fuel filter and it had fuel in it and plenty of pressure. the other times I did not check the pressure, but when I go to prime the fuel system it is as if it dont have any pressure. I dont have any noticeable fuel leaks that show on the ground or on the side of the engine. But once I get it running I have no problems out of it for the whole week. Only if it sets for 2 days does it do this. so now when I think about it I will crank it up and let ir run until the air pressure builds up and then shut it off over the weekend. But that's not fixing the problem. I need to fix it, what ever it is. ANY SUGGESTIONS OUT THERE???????

Answered! View the answer I have this problem too

Is this a good question?

Score 0

Comments:

Richard, did the gentlemans suggestion fix the problem? I'm having the same issue but a little more severity... can you send a pic of what it looks like anybody...

by

Add a comment

2 Answers

Chosen Solution

If I remember correctly on the 3406 there is a one way check valve just under the primer plunger that goes bad sometimes and allows it to lose the prime......''italic text''

Was this answer helpful?

Score 1

Comments:

Thanks Blackwood,

I will check that , would that be something like a plug in vale or would it be bolted on?

by

Is this check valve under the plunger or....?

by

Add a comment

i've had this problem twice over the years (once just over the weekend)-with an old series 60-and both times prime was lost through the fuel lines. to diagnose the fuel lines, i connect a dc powered diesel fuel pump from harbor freight to each line and seal it at the end and then pressurize to see if fuel starts leaking-either though a crack, or at the jic fitting hose ends. i would think you have shut off valves on your fuel lines, so you can just close a valve, and disconnect the line your testing at the other end and connect it to the pump. until you do figure out the problem, you can shut your valves while the truck is sitting to prevent fuel from draining back into the tank(s). every truck i have operated has 2 t shutoff valves on top of the transmission-1 for the flow to the engine, and 1 for the return flow-where the 2 lines from the tanks "splice" into 1 line. another shutoff valve i have always had is connected on the filter head after the fuel pump and before the engine head. the purpose of these valves is to prevent losing prime when changing filters or in the event of a faulty line. you could also check to tighten your fuel lines at the jic fitting ends.

Was this answer helpful?

Score 0
Add a comment

Add your answer

Richard will be eternally grateful.
View Statistics:

Past 24 Hours: 7

Past 7 Days: 31

Past 30 Days: 162

All Time: 7,662