Alright guys I am experiencing a miss at all RPMs. It is pretty noticeable near the engine with a knock, but is extremely noticeable at the exhaust. It is easy to feel that the exhaust is "puffing" per say. Now I just replaced the injectors with a new set of 125hp sacs, but the miss was prevalent before the injector swap. The swap did not make a difference. Everything sounds the exact same as before the swap. I have fuel squirting out of each connection at the cross over tubes while running.

MoparMan and I spoke on the phone earlier and have decided to take a systematic approach to resolving this issue.

Ruled out: 1. Injection pump: Always supplied good pressure, less that 10K miles and miss seems to only be in one cylinder. 2. Injectors: Swap made no difference.

Possibilities (Almost endless): Burnt/ broken valve, broken piston or piston rings, clogged cross over tube, valves way out of adjustment

 

I should receive the truck Friday from being painted and I can start diagnostics. 

The plan: 1: Pull valve cover and quickly check valve lash - just make sure somewhat close to spec. 2. Use an infrared heat gun on the exhaust manifold right were it come out of the head to try and narrow down which cylinder is missing. If that does work I will pull the cross over tube and replace it (I already have 1 new one that will ship out Monday). If that does not fix the issue I will do a compression test on that cylinder to determine if it is the bottom end or the head.

If the heat gun does not find a "cold" cylinder I will pull all injection lines and cross over tubes, then clean each tube and try to determine if there is debris in one of them. If I can not find debris in any of them I will replace them with the new one, one at a time. If that proves inconclusive I will perform a compression test on all 6 cylinders. 

If any of the cylinders are low on compression I will pull the head and determine what is wrong internally.

 

Any suggestions on the procedure or something else I can do to diagnose what is wrong with this thing??

Edited October 26, 201410 yr by TFaoro

arrggg..

 

  ya know,   I'm  going to  Holyoke  Co.   next week..     I  could  hump over to  Tfaoro's     just for the sake of  listening to it!

  On 2/6/2015 at 3:58 AM, MnTom said:

That makes me want to think there is a fuel deliery issue somewhere, but are you hearing a miss or are you hearing a lope? From what I have heard about the only thing the drilled cross over tubes do is cause a bit of a lope.

Definitely a miss! Some people say they lope - maybe with bigger injectors but not with my setup. I can hear this thing missing from 800rpm  2500 rpm+ when freewheeling. It also has a distinct "knock" like a cylinder is missing. Maybe I have an injection line that the outlet got smashed somehow?? I think I can replace the drilled out tubes 1 at a time with an "original" crossover tube and find which cylinder it is that way though.

 

 

  On 2/6/2015 at 4:07 AM, rancherman said:

arrggg..

 

  ya know,   I'm  going to  Holyoke  Co.   next week..     I  could  hump over to  Tfaoro's     just for the sake of  listening to it!

Come on over! I could always use some company 

This was 20-30 seconds after a cold start.

Really thinking it's cylinder #1. I could hold my hand on it while I couldn't on the others. I'll swap out that crossover tube tomorrow and report back.

Ok I put the normal crossover tube back into number 1 cyl and the miss is half of what it was before, so at least I've got it narrowed down to that cylinder. Any thoughts on what it could be? I'm thinking the line might be bad?

geez.  could be!    take it off and  look  closely for  kinks   Blow  through it with  compressed air both ways..   But I'd   think a bad line would be  bad no matter what the crossover tube  is in there!!

 

 

edit..  you SURE that  was  the ONLY  cylinder that was missing??    You may have only fixed  'half'  of the  miss...   What you are hearing now  may be coming from another  cylinder!

Did  the exhaust manifold heat up  faster with the different   tube?

Edited February 8, 201510 yr by rancherman

  On 2/8/2015 at 10:31 PM, rancherman said:

geez.  could be!    take it off and  look  closely for  kinks   Blow  through it with  compressed air both ways..   But I'd   think a bad line would be  bad no matter what the crossover tube  is in there!!

 

 

edit..  you SURE that  was  the ONLY  cylinder that was missing??    You may have only fixed  'half'  of the  miss...   What you are hearing now  may be coming from another  cylinder!

Did  the exhaust manifold heat up  faster with the different   tube?

No compressed air up here (college apartment), but I can pull it off and see if it's clogged at all. Maybe just the tip is screwed up I'm not sure.

 

I'll check the temp after starting in a couple hours. I'll make sure to feel all of em to see if multiple are bad. 

I guess I should throw my two cents in here seeing as I am the king of tracing down slite misses. lol Hey Mike this don't sound familiar. You know what it sounds like when it's hot right ? Now in the morning go out fire it up and if it is not as noticeable. Then we'll go from there.

Don't tell me I have a cracked pistion 

Will do. 

Go out when its cool 65 degrees start it and let it idle for about 5 min. Get a ear of it, you know what it sounds like right ? Now drive it 800' or so. Listen to see if you here it starting to miss. If no miss drive 1-2 miles pull over check. You see where I am going with this right ? If it has a cracked piston or cracked block it will pass compression test all day long, I even did a blow by test and it still passed that. At some point I will guess if its like mine was you pulled a heavy load and let the egts get to high. I pulled a D4 dozer on the hwy and pulled a steep incline and that's what did it on mine. I remember the temps were 1250 1300 for a few minutes and that was just enough. I spent right at 8k tracing it down, don't bother taking it to Dodge or Cummins they wont know anything more than us right here. Believe me I spent the money thinking somebody has run across this before. I learned a whole lot about these Cummins during that ordeal. I replace 4 IP , 4 sets of injectors, two wiring harness , four crossover tubes, (by the way change them every time you replace injectors), a rebuilt head, swapped turbos with my sons truck, about 3-4 apps, 3-4 cam sensors, two ecms even put another exhaust because I thought I was going insane hearing ****. I guarantee if it will set in your drive way and sound like the best truck you ever heard idling, then miss after a short trip down the road. Go find you another eng and be done with it. 

I don't take this truck to anyone. I do everything myself as you can see by this thread. I also won't spend money on parts unless I know something is wrong.

I went out and started it as you suggested. It sounds like it starts missing as soon as it fires. Also how would a single crossover tube make such a difference?

jlwelding;

so what did yours end up being..    piston?  and  where was  this  crack at?  ring land?

As for the cross over tubes go if you notice when you put the injectors in the hole there is play side to side and in and out. When you tighten down on the injector the crossover tube will crush a tiny bit. The crossover tube is a soft metal and that is how it seals it's self off. You might get by one time with old tubes but if your luck runs like mine, you better get new ones. You could have a leak between the tube and injector seat. If it misses right off the bat you got something else going on other than what I described. What I do is put the injector in push crossover tube in till it seats, tighten down the injector. Install all injectors this way then tighten down crossover tubes behind intake bleed the rest and tighten them.
I sold the block with cam, pistons,crank still in it, the guy said he was making a twelve valve out of it so he pulled all the parts and just used the block. I told him if he had any issues with it to bring it back and if he found anything he said he would let me know, I never heard from him. 

 

I've tried brand new crossover tubes, drilled out tubes, old tubes you name it. I don't think I'm going to find this anytime soon... Maybe this weekend I'll pull all of the lines again just to make sure they are clear and the ends look good. 

Over the summer I do plan to pull the head, so I guess that's the next step.

Try a new set of lines? (new/used)

  On 2/10/2015 at 2:47 AM, Texas CTD said:

Try a new set of lines? (new/used)

I haven't. I'm currently looking for a set to try.......

I really cant see it being lines, ya think?

i think it's a cracked piston as stated before, or maybe crack elsewhere.

  On 2/10/2015 at 3:58 AM, jlwelding said:

I really cant see it being lines, ya think?

Not unless there is a kink or one of the tips is smashed. I don't know but either way I'm going to run the snot out of it until I pull the head.

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.

  On 2/10/2015 at 5:05 AM, Killer223 said:

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.