contribution/balance codes?

What causes contribution/balance codes besides a bad copper washer, bad rubber o-rings or bad internals? I had a P0269 code for cylinder #3 contribution/balance. Pulled #3 injector and found absolutely nothing obvious. Washer and o-rings looked perfect. Then sent it to MPD and they found the plunger to be worn badly. Had a new one built and reinstalled this morning. Started it up and idled great for a few minutes. Then all of a sudden it started to get a rough shakey idle again. It threw code P0269 for cylinder #3 again. Pulled #3 injector and everything looked perfect. I'm stumped and have no clue what's causing the contribution/balance code. Any thoughts?

Check the harness for chafed spots.

I was gonna try that tonight. However...won't a bad connection or chaffed wire cause circuit low/high codes instead of contribution/balance codes?

On that I'm not sure. I remembered the earlier models had issues with the harness chafing.

Do you know if they changed the solenoid?

Probably not what you want to hear, but you could have low compression on that cylinder.

Compression on that cylinder was checked and the rest of them were checked and all had great compression.

Swap it to another hole see if the problem follows. That will rule out the injector. I'd be checking the harness real well first, wiggle all the connections and plugs I had the same thing happen and it was a bad connection on the center plug for the ficm.

To me it seems electrical...like something with the harness. I have a new one I can swap in tomorrow. Fired it up again tonight after I reinstalled the injector again. Idled great for like a couple minutes then started idling rough. I checked for codes and it now threw one for cylinder #6 contribution/balance. Cleared codes and restarted. Now it stopped throwing a code for #6 and keeps throwing code for #3 contribution/balance. It does it intermittently tho. It'll idle great for a few minutes then idle rough for a little bit...then go back to idleing good. Another thing I noticed is that when I crank on it to start...there's a second delay or hesitation before I fires up.

I just had a truck in here three days ago was very similar.

Does your truck idle like it's running out of fuel pressure at all or shut off?

Wiggle the harness while it's doing it see if anything changes. Shake everything around. Fuel pressure is in check I assume?

The truck doesn't stall,die or shut off on it own. Fuel pressure stays at 60psi at all times and never drops.

well....this morning I swapped out the ficm with a good spare I have. Still has the same rough idle with P0269 code. So then I decided to swap in a new injector harness I had. And again...same thing...still rough idle and same code. I'm at a loss right now. I has good compression on #3 and the rest of the cylinders...copper washer and rubber O-rings had all checked out ok. Only thing I can do is pull the valve cover off again for the 3rd time and swap #3 for #1 and see what happens. Either the symptoms will stay with #3 cylinder or travel to #1 cylinder. But I'm gonna need a new T40 torx socket before I do anything cause I rounded/stripped the bit.

Swap em around and see what happens.

Yeah gonna start tear down for the 3rd time tonight.

At this point I would suspect the solenoid is shot. Put a new one on when you swap cylinders, that way if it is the problem, it's then fixed...

This is a newly built injector from MPD I just received on Thursday. Haven't even put 1 mile on it. I doubt its the solenoid. It flow tested fine before it was shipped. I have it torn down again for the third time and have #3 and #1 injectors out. I will swap them tomorrow and see what happens. I'm hoping to see my issue go to #1 cylinder. If it stays with #3 then I pretty much know that it's an engine issue and not an injector issue.

New isnt always good, dosent matter who built it. Once you swap it to another hole youll know for sure.
Let us know what happens, you checked all the valvetrain etc just to be sure thats all good?

Ironically my truck started idling rough, then fine then rough again. Throwing a P0271 code now.

Little update. I swapped #3 injector with #1. Started the truck with valve cover off. Rocker arms and push rods looked to be moving the same as the rest. Didn't notice anything out of the ordinary with the pushrods or rocker arms. Valve springs all seemed to look good also. After startup I started to get a contribution/balance code for #6. I erased it and it came back like 5-6 times just idling in the driveway. It threw nothing for #3 or #1 after he swap....was completely baffled. So I let it sit for a couple hours and restart. Now I stopped getting codes for #6 and consistently get balance code for #3 again. I'm at a real loss why #6 started acting up. I decided to pull the hpo rail and swap it out with the one off my spare engine. I'm hoping maybe the rail is messed up somehow or the knuckle on the rail where it sits on the injector. Gonna finish it tomorrow and see.

How did you make out with this? Solved?