running rough

[pedro_8149]

hey guys, so yesterday i did a 350km road trip nothing to serious. truck ran great there and back. on the way down to my destination it ran good no problems idled fine when i pulled into where i was going was in with friends in the building for 3-4 hrs came out it started just fine we did a cruise around town before we headed home. i drove the 160km home and ran flawlessly. pulled into buddies driveway put it in neutral and it started to run rough, like shaking. dropped a couple other friends off and their house and same thing it started shaking. my idle is about 550rpm, and 1000rpm and and up its perfectly smooth. it sat all night, i went out to start it, fired right up as if it was just running i was leting it warm up and right away it started to shake and run rough and this morning it had a blueish smoke till it got up to operating temperature. i went out driving runs smooth and again any time it idles she starts running rough. i have no clue as to what it could even possibly be or where to even start looking . any ideas? if you need more info ask away and ill try to answer my best. i got a video of it running this morning and a video of it running this evening but have to wait till later tonight to upload them when i am at home.

 

[pedro_8149]

so truck sat all day, started it up to leave where i was at starts right up and runs rough right of the get go, hit high idle and it runs perfectly smooth, drove home no problems idled at a couple stop lights it was smooth, ive got a decent grade / length hill coming to my house and i pulled the hill in OD at about 55km/hr no prob pulled in my drive way put it in park let it idle a minute and man it shakes and bounces rev it up to 700-1000 and it smooths out. its to late to upload a video tonight so ill have to do it on my spare minute tomorrow at work. but if theres any ideas / suggestions post away thanks guys

 

[Can30Diesel]

From what you mention, it sounds like either air intrusion, or lift pump/injector pump. I'm suggesting injector pump only because I am coming from experiencing 4 different injector pumps dying 4 different ways and your problem is sounding too familiar. However having said that, you have a nicely built truck, so its hard to believe that could be the case. Have you had a chance to check for the usual suspects? Leaky caps, etc...

Has anything changed recently?

 

[franklin2]

What I would do is get it idling rough, and then get up in there and crack loose each injector line one at a time till they leak. If a injector makes the engine idle worse, we can assume that one is working. If a injector makes no difference or makes the engine react different than the other ones, there is a problem in that cylinder. Sticky injector?

 

[icanfixall]

My engine did this too. Found it to be the delivery valve in the injection pump. What happens is the valve leaks when the engine is idling and causes fuel to leak back after that cylinder is closed off in the injection pump after the totor has moved to the next cylinder. It requires the pump to be removed from the engine and the end of the pump removed to get the valve out. We have different sizes of these valves too so don't just buy one at a pump shop till you have yours in hand.

 

[pedro_8149]

Nothing has changed on the truck recently, ive looked for fuel leaks and everything is dry, the lift pump is about 2 months old and the injector pump is just under a year old. Ill have to check the injectors while its running and cross them out. The valve that stick in the back is that a difficult thing to look into? Or is it a pump specialest type thing.

 

[riotwarrior]

I'd start with simple stuff first, FUEL FILTER, and or do a quick diesel purge of your fuel system. Maybe that will work for you. No mechanical stuff to do other than swap a filter.

Check pressure of lift pump at schrader valve with a proper gauge.

Once the easy things are ruled out it would be time to start thinking $$$ things


JM2CW

 

[franklin2]

That's a good idea. Take the fuel filter off, get a new one or dump the old one out, and fill it back up with diesel klean, Howes, or I think some people use automatic tranny fluid, and run the engine for a little bit on this and then shut it off and let it sit. Then drive it and see if it freed anything up. I believe I read on here that cured some people's fuel system problems.

 

[pedro_8149]

Sorry i lied i forgot about puting a new filter on just about 3 weeks ago thats the most recent thing ive changed. And i run a fuel preasure gauge and at idle its 7psi and running at any given rpm it maintains 6.5-7 psi

 

[icanfixall]

You can replace the delivery valve but. Its a valve that has to be the correct diameter so might want to have a shop do it. If you remove the pump from the housing lease mark the joint with a center punch. then all you do is match up the 2 half circles and the timing will be what it was when you removed the pump.

 

[pedro_8149]

Ive marked it from when i did my pump previously. Im goin to check out my injectors tonight and ill report back.

 

[pedro_8149]

Icanfix all how do i measure the valve part once pump is removed, abd can i reasemble it to continue using my truck i really cannt have it down more then the day cause i use it for work.

 

[gdhillon]

Jo, I have my old pump in the garage if you want to swap em while you get your ip fixed....my truck is n/a but id think it would getyou from point a to b

 

[pedro_8149]

So i went over my injectors this evening. Once i crack them open it really runs rough. I checked everything for leaks sprayed all the plastic caps with break clean while it was running cause it would make it run rough if it was sucking air. Sprayed everything down that was a joint of some sort of connection from fuel tank selector forward and no difference was made. So i think its safe to rule out the injectors and connections for air intrusion and not firing properly. I guess next step is look at swaping pumps. I also dumped a litre of atf in my tank to see if that helps free something upp.

 

[franklin2]

Did you crack the injectors open one at a time? It's sort of like pulling the sparkplug wires off one at a time on a gas engine, so see how that cylinder is contributing.

Just to let you know, you will not get air intrusion around the fittings on top of the engine while it's running. That only happens when the engine is turned off. The places air will affect the engine after it's running is the suction side of the fuel pump(the lines and fittings from the fuel pump to the fuel tanks).