Miss at all RPMs

[TFaoro]

What if you somehow by accident got a piece of dirt or any debris under the sealing washer of the injector it can let combustion gas into the crank case. also causing a the smoke and possibly a slight miss.

Good thoughts here, but I know that isn't the case for a couple reasons.

1. I've had 3 sets of injectors in it and on every one of them the copper washers look good and sealed to the head. No black streaks where the compression could be blowing by.

2. That leak would actually push compression into the fuel return system inside the head and back into the tank. I would have high pressures in the tank when i take the cap off.

3. I actually had a copper seal go bad a year or two ago and push compression into the tank. These symptoms are not that.

[TFaoro]

Alright Mr. Cummins your move: 6 new crossover tubes from cummins, 6 new Orings, and 2 grid heater gaskets

 

[Mopar1973Man]

My cross over tubes so far have made a good change to my truck and how it runs. As for misfire I'm not going to call it cured yet till I do some long hauls and see.

 

Now as for my grid heater gasket I love to steal yours. But mine are on there way and be at work by Monday.

[TFaoro]

Cummins dealer was the cheapest place I could find the grid gaskets! 5.28 each

Tubes were 25.67 each with O rings. O rings separate were 18.95 smh! Came out to be a few bucks more expensive than ordering, but no shipping and I got them tonight

[Mopar1973Man]

That's better that what Rocky Mountain Cummins (of Boise, ID) quoted me for one cross over tube at $166.40 a piece (or $998.40 for six).

[Yankneck696]

RAPE !!!!!!!

 

Ed

[TFaoro]

Well I have everything in and...... No luck. It doesn't sound like the miss has changed at all. Sounds internal to me. The whole fuel system has been gone through

[CUMMINSDIESELPWR]

interesting...

Edited March 7, 2015 by CUMMINSDIESELPWR

[Mopar1973Man]

Ok. Question do you do the compression test on a cold engine? You might do a blow by test on cold and hot and see if there is a measurable difference. Then if you can quick enough pull the injectors and re-do your compression test hot. I'm wondering if it like JL Welding where he had a cracked piston that would only open up after fully heated.

 

Plain weird... Diesels are such simple engine only requiring compression and fuel. To have a misfire means either one or the other is missing.

 

The only thing that crosses my mind as a odd factor is possibly timing? I know the lines if removed in a group you can't mess up. front group is 1,2,4 the rear group is 3,5,6. Firing order is 1,5,3,6,2,4. The only reason I'm thinking this is common for people with gassers to cross plug wires and get a odd miss that never goes away.

 

So did your fuel leak stop too on the manifold?

[TFaoro]

Honestly I'm tired of trying to find this miss. I'm not going to do anything else until I pull the motor out. If there is something wrong down inside, I'll see it when the head is off. I will also see if the timing gears are all lined up at the same time. injection lines are in the correct order. I took them all off and cleaned them with a green scotch brite pad.

 

It appears like the leaks have all stopped but I need to go wash the motor to be certain

[AGPTurbo]

How about a valve hanging open for a split second? Maybe pull the valve cover and watch while cranking?

[Dieselfuture]

I was told long time ago " The longer you wait to fix something, the easier it will be to diagnose the problem".

[CUMMINSDIESELPWR]

pull the head already, have the head pressure tested and inspect the pistons. dont throw anymore money at.

Edited March 9, 2015 by CUMMINSDIESELPWR

[dorkweed]

pull the head already, have the head pressure tested and inspect the pistons. dont throw anymore money at.

 

 

 

Agree^^^^

 

This is sounding more like a piston or head gasket thing!!

[Mopar1973Man]

Man TFaoro, I wish your problem was as easy as mine. After changing the cross over tubes and this this weekend hitched up and went to Huntington, Oregon to go out for the first RV trip of the year. Absolutely no more miss and the truck ran strong.

 

I hate to say it but I guess you going down that road of full pull down to see what's going on. Something isn't right cylinder wise.

[TFaoro]

Little update here. Thanks for the thoughts guys. The miss doesn't seem to have gone away but I don't think the old tubes were completely seating against the injectors. I can now pull more boost, spool the turbo quicker, and have lower EGTs. That dang miss is still there though. Weird thing is when it has a significant load on it you can't tell it's there.It still makes Tons of power, spools really fast, and has zero blowby.

 

To the head coming off... That will happen in time. Right around the middle of may the motor will be on the garage floor, so I'll do it then. Thanks again everyone for the help!

[TFaoro]

Little update here: I'm starting to get a bit of blue smoke when idling and high idling. Even when the engine was up to 145deg it still had a decent haze coming out of the tail pipe. I haven't noticed any consumption on the dipstick though. Maybe this is related, maybe it's not. I'm also noticing that warmer ambient temps seem to make it worse, along with switching to 6cyl mode when idling. I'm not sure if that's related to timing or??

I'm getting pretty ancy wanting to pull the motor! 4 weeks and it should be coming out.