ryan10

Hey guys, i went on a trip, and everything was going fine, but then my oil pressure just dropped to nothing and the truck started to run real rough. it sounded like the truck was missing. if you gave it gas, it would smooth out a little, but still ran rough. i checked the oil and it was fine. I also checked for oil in the radiator but nothing. also, when i check the oil it looks like there is more than there was a few weeks ago when i changed it, and it is not fuel. what could it be?

MikeThomas

Smell the oil reeeaaal good. Cummins only make oil one way: bad lift pump pumping fuel into the case. The lift pump could be going bad and allowing air to the IP, thus allowing it to run rough. Oil thinned by fuel will also cause the drop in oil pressure.

LOGAN

check the lift pump and change it, then change the oil and filter and go from there, use the really cheap stuff from autozone so it will only cost ya like 15 bucks to change it, start the truck up and let it idle washing the pan and everything out with the cheap oil then change the oil and filter to the good stuff, i always do this with a motor or tranny when something like that happens, sounds like a lift pump to me though.

ryan10

Ok, thanks. so the truck will lose oil pressure with a bad lift pump also? what do i need to do to change the lift pump?

bloodhound51

just a lift pump, can be bought at napa,autozone,etc.
usually an order item
you might try a diesel shop they may stock it
if not a chrysler dealer will have it but they will want double the price a parts store can get it.
its about $75 at napa

ryan10

Ok, how do i replace it? also, i lost my power brakes when all this happened?

ryan10

can somebody please tell me if all i have to do to change the lift pump is disconnect the lines and put in the new pump, then re-connect everything? also, why would i have lost my power brakes when this happened?

jogl

Yes, as long as there is not a lot of other stuff in the way the lift pump swap should just be as you described. You may need to loosen a line at the filter and bleed out the air from the new LP. It could also be the front seal on the IP (if I am not mistaken) or a bad injector that is letting fuel into the crankcase. However, change the LP first, cross your fingers that it isn't the IP or and injector and fire it up.

How much extra oil is there?

I doubt that the brake problem and fuel in oil problem are related. I would get the engine running right first and then worry about the brakes.

JP.

dieselJon

Well, from what I have read on here, the lift pump is as simple as unscrewing the line and unbolting it, the slap the new one on.

Now on the power brakes, did you lose the vacuum for CC, if you have it? And I think the HVAC controls operate off of it. If they do, did you lose them also?

Jon

wannadiesel

It's also possible that the front seal on the injection pump has failed. The way to check for this is to remove the oil fill elbow and use a flashlight and a mirror to watch for fuel coming down from behind the gear while somebody pumps the manual lever on the lift pump.