Injector or egr?

[cwendel]

Okay, so I had a bad nox 2 sensor about a month ago. I had run the truck prior to the final repair for awhile. Now since the repair, I have had an issue when it warms up. The motor had a slight knock when cold but the knock was from the top end. It has now developed a rattle when warmed up. The rattle sounds like either a bad accessory bearing or the water pump but none are creating the sound. Next is the injectors as I already redid the valve lash. Redoing the lash seamed to help the cold knock but now the rattle is back. I am more familiar with gas engines and would describe the rattle as the truck detonating on low octane or a bad coil. None of those here so, must be an injector issue. Now fast forward to today, towing home from a camping trip pulling 8,000# and it feels down on power down low and up high, no issues in the mid-range. Ran the scan tool at home and found the egr commanded to 95% but the actual was at 0. No codes are set and no check engine lights. Egr flow is less than 1 so I am stumped. Also, misfire mask reads between 1.2 and 2. If there is the miss, then a bad egr would be a cause but no codes or smoke.
The truck is a stock 2013 2500 with, of course, the 6.7. any help with this would be great. Thank you all.

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[walla2k5]

Okay, so I had a bad nox 2 sensor about a month ago. I had run the truck prior to the final repair for awhile. Now since the repair, I have had an issue when it warms up. The motor had a slight knock when cold but the knock was from the top end. It has now developed a rattle when warmed up. The rattle sounds like either a bad accessory bearing or the water pump but none are creating the sound. Next is the injectors as I already redid the valve lash. Redoing the lash seamed to help the cold knock but now the rattle is back. I am more familiar with gas engines and would describe the rattle as the truck detonating on low octane or a bad coil. None of those here so, must be an injector issue. Now fast forward to today, towing home from a camping trip pulling 8,000# and it feels down on power down low and up high, no issues in the mid-range. Ran the scan tool at home and found the egr commanded to 95% but the actual was at 0. No codes are set and no check engine lights. Egr flow is less than 1 so I am stumped. Also, misfire mask reads between 1.2 and 2. If there is the miss, then a bad egr would be a cause but no codes or smoke.
The truck is a stock 2013 2500 with, of course, the 6.7. any help with this would be great. Thank you all.

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There are a few fine technicians around here, I'm sure they can help you out when they see this.

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[cwendel]

Some extra info
The truck has 36,000 on it while the short block has about 10,000. Was changed by the dealer after they effed the rear main seal and screwup the crank surface. There was a report from the work that cylinder 1 had carbon build up and that the tech cleaned the head. They also broke a sensor but I truly forget which.

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[DDP]

Some extra info
The truck has 36,000 on it while the short block has about 10,000. Was changed by the dealer after they effed the rear main seal and screwup the crank surface. There was a report from the work that cylinder 1 had carbon build up and that the tech cleaned the head. They also broke a sensor but I truly forget which.

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Did they check out why that one only had carbon build up? Any notes on injectors or fuel system?

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[cwendel]

They never did. Typical dealership in my area. I changed both filters just before the trip, they were dirty but didn't look it.
The injectors are the original and I have no hard starting issues. I also have no smoke but did have a strong diesel smell in the exhaust while the truck was warming up before coming home with the camper yesterday morning.
I ordered a block off for the injector rail and am going to check the fuel pressure from the tank. The rail pressure never varies much more than 500 psi from the commanded pressure.

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[cwendel]

Okay more info. Seems I miss read the repair order and they only cleaned the carbon from all the valves in the head. Also looks like they pulled the injectors at the same time and replaced all of the seals and gaskets. They also replaced the rail pressure sensor because they broken it while pulling the motor by hitting it with the pulling bracket. Should have caught that way back then. I may have the source of my problem is that sensor is bad or the rail was damaged. I know the truck runs but the more I learn the more I think I like having to syncronize Webber carbs on a jag.

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[Dwelsh]

Honest opinion. And its just that. But i would lean more towards emiisions junk than anything. Even on gas 75% of performance issues/ check engine lights is emissions related if not more

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[cwendel]

I am thinking the same.
Last night I took the truck for a drive and data logged the egr and the fuel rail pressure. Seems the fuel rail pressure always lags behind the commanded pressure values
When accelerating, it can be over 1000 behind before catching up and then seems to over run the commended when I let off the throttle by at least the same amount. I found that very light throttle increases had no issues while normal did and it was those normal issues that lead to wide variations in rail pressure. I am starting to wonder if the FCA is starting to go and this is just the first signs.

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[cwendel]

Anyone know what the idle rail pressure should be on these trucks? Just so I know if what I have is just low.

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[cwendel]

Alrighty, so cleaned the egr valve. It was not bad at all, fairly clean. But the map sensor was a whole different issue. That bugger was really carboned up. Cleaned that and the truck seems better. Will get a chance to drive it tonight but idle was already better and there was no rattle when reving up from idle.
Now what other sensor is used to measure boost reference and where the hell is it hiding?


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