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Priming the Oil Pump

11K views 23 replies 8 participants last post by  Russell 
#1 · (Edited)
I'm trying to get some oil pressure before I start my engine but after about a total of a minute of intermitant cranking I still haven't gotten any oil flow. I've got the oil line off of the turbo and have checked the oil filter. The engine has plenty of oil, has a new oil pickup tube, and when the pan and timing cover were off everthing looked fine. Is this normal to take a while to get it to prime or is there something wrong?
 
#2 ·
it's normal. I don't have oil pressure for about 3-4 seconds after the engine has started to run. So for your initial prime, I'd just start it and see if you get pressure witin 10 seconds.
 
#3 ·
I tried starting it but when I cracked the injectors and got no fuel. So I pulled off the fuel line to the lift pump and put it in a can of fuel and still didn't get anything to the injectors. The lift pump is getting suction and when I loosened the banjo bolt for the fuel line to the injection pump I was getting fuel when I pushed on the the primer button.
 
#7 ·
Don't know if it matters on a Cummins, but I've had a few engines that wouldn't prime after having the pickup off the pump.

on those I was able to back feed oil down the galley to the pump from the filter (or one of the plugs that fed it) with a small pump can (yep, just a regular mechanics' oil pump can).

Worked good after that, but I'm unsure if there is a convenient port you could do that with the filter mount you have.:confused:

Hope that helps.

Good luck with the starting issue.
 
#8 ·
A neat trick I've done on Cummins engines to get the starter to crank faster, in injector bleeding, or oil priming, is to totally block off the air intake, then crank on it. Once the intake gets negative pressure, it causes the engine to turn over easier, which speeds up crank and cam speeds with the starter.

Try it, you'll see that it works.

Mark.
 
#9 ·
you should be able to hand prime the pump, loosen the overflow fitting so it is easier to get the air out. pump the hand primer till you have fuel coming out of the injection pump, tighten the fitting. then crank the engine over with the injection lines loose. Dave
 
#10 ·
Loosening the overflow fitting did the trick to get it primed I've got fuel to the injectors but still no fire. I guess I'll have to keep trying to get the air out of the system in the morning.
 
#11 ·
I seem to have better luck with the injectors opened slightly apposed to all the way.I tighten the nuts down then back off a 1/4" turn.the fuel should shoot and spurt,hitting the hood and windshield.
 
#13 ·
Well I've reached a whole new level of WTF I was cracking the crap out of it getting good fuel flow out the injectors but still no fire. So, I gave it wd40 while I cranked it then either still not even a sputter. At that point I decided it was either pump timing or valve lash so I pulled off the front two valve covers to check lash and cranked it with a socket to get to tdc but the rocker arms didn't even move. So I'm thinking either the cam is broken or the key for the gear is sheared/missing. I've got a picture from when I did the kdp in the picture you can see a white mark across the cam and gear. At the time I didn't think anything of it but now???
 

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#14 ·
I got the timing cover off and pulled the cam out well, the front of the cam. It's broken just after the first cam bearing and it also has a minimum of a bent push rod which means I need to check the valves and etc. So I'm pulling the engine tonight to tear it down.
 
#15 ·
when my brothers 12v broke the cam (timing case bolt fell out) the cummins dealer pulled all the injectors, and gave the engine a leak test by blowing air into each cylinder with all the rockers off. no air came out the intake manifold or the exhaust pipe,that means the valves were not bent. so they just replaced the 6 pushrods and lifters along with the cam. no need to take the head off if you don`t need to. when you are blowing air into each cyl, if the headgasket is bad you will hear air comming out the next empty injector hole,if the rings are bad you`ll hear air comming out the crankecase. they had an adapter made out of an old injector gutted and with a air hose fitting welded to it. they shot shop air in at about 125 psi. hope this helps your diagnostics.:idea:
 
#17 · (Edited)
Well I pulled the engine and tore it down the cam broke in two places, one broken lifter, about 5+ bent push rods, and about 3 bent valves. The pistons hit the valves on #1, 3, 4 but I think the pistons will be ok just need to check for cracks. I don't know what caused the cam to fail other than bad metallurgy because, there was nothing floating around inside that could have done it. I'm not sure whether I should just buy the parts individually or get an overhaul kit if I can find one with the cam.
 

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