hard start/running rough
 

Hey, something weird happened 2 times on the weekend.

Truck was running fine as usuall. Loaded up the quads and then tried to start her up, and it was hard to start, it was running really rough. You could feel the engine not running right throughout the body, as I gave her some fuel it wouldn't keep a steady RPM, and it sounded like a rocker or a valve was ticking/knocking really loud, and as soon as it started the let go of the pedal a bit it would stall. Fired it up again and same thing, hard to start, running really rough and that same sounds. Engine cut out again.

Tried to start it again, but now she ran fine, no issues as per normal. Drove it home and no issues.

And yesterday the same thing happened again, after 3 hard starts she was running fine, and drove quite a bit, and came into work this morning without any issues.

What could cause this?

Thanks

Fuel shutoff possibly not lifting all the way up :c:

Last night we checked all the lines, no apparent leaks, no cracks, and doesn't seem to be sucking any air. If it did, this would not be an intermittent issue. And it only does it when its warm. Cold starts are not an issue at all. So it did it last night, listen to each injector, and the ppump. the only thing we could think that is causing the issue it an injector that might be sticking or a piston in the ppump that could be sticking a little, which would explain why we hear a loud tick/knocking sound.

Chris at the shop has seen this happen once or twice before that a piston in the ppump was sticking a little. So this morning I fill her right up, added some extra lube with my additive, and I wil see if this corrects the issue.

I will let you know what comes out of all this.

Thanks

My issues has dissapeared. I guess it just needed some extra lube and additive, to clean out what ever was caught in the pump and/or injector.

Thanks for the help and input from everyone.

well, my issue is back now, and the only thing we can find, is that Ppump. One of the pistons in the pump sticks, and that would explain the knocking sound that happens when the truck is running rough.

Chris at the shop is surprised himself to say that it's the ppump as he is a hardcore 12 valver, and this would be the 3rd time ever that he has had to say that it's the ppump that is the cause.

So now we are looking around to find one, and throw it in and see how my rig will run after that.


I will keep you posted.

Thanks

they're obviously great pumps, but seem to have about a 250k mile reputation... anything after that seems to be borrowed time. i'll probably get flamed by somebody who's "borrowed" a few 100k more, but, that seems to be the way it goes

I belive you G U it seems that the Core of the 6BT is the highest service life and everything that bolts on it is around 250K. Save the Melling. I have this weird knock that has started in mine and wonder if isnt the injector pump. cause it wasnt there b4 and just had oil change and valve lash adj. suspect the air charger is due for rebuild too now borrowing at 337K miles.

Does anyone have instructions as to how to rebuild the P-pump?

The key to having a ppump last longer is additives. The pump get lubbed by engine oil, but the pistons/plungers were lubbed with diesel, but now with ultra low sulfur there is not enough lubricating agents. So added lubrication is needed to keep the pump in proper order and function.

Mine is just shy of 375000 miles. and this is the first time that theres has been any real issue with the fuel engine and components. It's a daily driver, and would not change it for the world. I run power service additive, and the odd time I will add 2 stroke oil for added lubricity.

The old farmer that owned it before never ran any additives, and poor quality of fuel lead to the premature wear on the ppump. This is the 2nd pump that the boys at the shop have changed. So make no mistake, this is not a problem that is common. Just bad luck.

I know of a few guys that have north of 500k miles and have had no issues and they work them almost everyday.



If I'm not mistaken, you have to be a certified pump technician to pull it appart and rebuild it. Once it is rebuilt they have the bench test the pump. Make sure that it flows right. I don't think I would attempt to rebuild the pump on my own. But now that I have a core pump i might look into getting a Dragon flow in a few years.

Thanks

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Newby 98

if it was the pump that you hear knocking, you would have the same symptoms that I had, and your truck would be running rough. A plunger/piston starts to stick, then you will hear a knocking sound as the roller taps the bottom of the piston. Which means that you are not getting any fuel to one cylinder. Thus your rig would not be running right at all.

This is based on what happened to my truck.

Thanks