Cat C15 Fuel Problem

haha its all good friend

 

Do you have heavy smoke from exhaust on start up after the truck sits, engine off, for a period of time?
Injectors could be bleeding down.
I have 2 MBN CATs, both in 2004 Pete's, both have manual ( hand) primer pumps on secondary fuel filter housing.
One went bad at just over 1.1 million, I replaced the other truck primer as well.
Unscrewing primary fuel filter will, of course, cause air to rush in as fuel is displaced, thus travelling to its lowest point, the fuel tank(s), hence fuel level within that filter will be lower, which is normal.
If you have the somewhat common issue with the primary fuel filter housing no longer able to seal itself with positive pressure ( its customarily under negative/ suction pressure) which occurs when the engine is not running, air displacement at that housing creates a void within that housing's seal, fuel bleeds back, fuel from higher points
( the pump, head, secondary fuel filter housing , fuel pressure regulator valve in the secondary fuel filter housing, etc.)will drain to that void within that housing, causing a loss of prime.
Check to be sure the primary filter , as well as secondary filter , are both tight, but not so much that the rubber seal has twisted.
Also, CAT has an issue they acknowledge, with " some", not all, of their fuel filter heads. The center post, which fuel filters thread onto, come loose. When you last changed the primary filter, it could very well have backed off, causing the threaded orifice in the new fuel filter to bottom out, so to say, on the post, but not on the head of the housing where the seal makes contact.
Think back, did your kiss of prime begin shortly after changing fuel filter's, specifically the primary filter?

 

So hold up a min. What i was calling the primary fuel filter is the filter thats mounted under the housing where the hand pump will, or will not be.. am i wrong? And my other question is i was told by the local cat guy a couple years ago that mbns didnt come factory with handpumps? The only other 2 mbns ive seen around here has not had them, and theirs, and mine are original housing from factory. So either the cat guy was wrong, or If the cat guy was right, what would be the reasoning behind adding one?

 

Primary filter is frame mounted, secondary filter is the engine mounted one. You could order with or without hand primer pump.

 

Learn something new everyday. Thanks for clearing that up for me. Aint the first time that cat dealership made me look like an idiot smh.

 

if its the supply side of pump, no it wont give you starting problems unless the fuel pump is going bad. The pump should build sufficient pressure within 2-3 seconds. If its the discharge fitting side, then yeah it mind give you problems. Either way, the flare fittings you can get at any home depot and are easy to install. The pump is also easy to remove install. Its only 2 bolts. New pump and gasket is about 180 bucks or somewhere around there.

 

Think of it this way bro, the frame mount is the primary becuase its the first line of defense. The secondary which is mounted to the block is the last defensive measure. This is obviously why you never hand fill the secondary and is recomended to use 2 micron cat filter. Only use hand primer to fill the filter or unthread the messy check valve and crank till fuel comes out. i prefer the hand pump. The primary i hand fill. Dont matter if i spec of dirt gets in it, it wont make it past the secondary. Im sure you know most of the stuff i just said. I just started rambling