excessive moisture in egr valve

[JimT]

(12-26-2020 )williamsbuilding Wrote:  I'm sorry if I've wasted your time.
I have done egr tune up about 20k miles after inflame, including egr temp sensor, delta p, exhaust manifold pressure sensor, dpf delta-p. The back pressure sensor tube was replaced during rebuild as I requested. At this time it began passive regens again till lately.

That statement points to the first place to start looking. Start by inspecting the back pressure sensor tube for clogs, check each sensor, including the imap, for carbon build up and clogs. Then, if they all check out, start inspecting the electrical parts. Check each sensor to make sure it's providing the proper electrical readings. Check all the wires and contacts for corrosion and/or damage. TEST (with a multimeter) all the wires and wiggle them around to look for HIDDEN issues inside the wires/wiring harnesses. You could have some intermittent problem that occurs when bouncing down the road. The split second anomaly could be enough to inhibit a passive regen.

Someone with Insite needs to look at ALL sensor data. There's a chance that the ECM could be just starting to go with the only signs being intermittent corrupt data. Probably NOT the issue, but it's possible.

(12-26-2020 )williamsbuilding Wrote:  Turbo and dpf were replaced shortly after rebuild.
Egr cooler replaced at rebuild.
Doser is less than 120k miles and cleaned head whe I did egr tune up to eliminate it as suspect as best I could.
I do not yet have software. Hope to get it soon. Reason is thought it was cost prohibitive until waterloo post.
I'm not afraid to wrench a bit, but hate to do all of it on my time off.

I wouldn't be the guy to do my own inflame or head removal, don't have and don't want a full on shop.
Forgive me if I wasted you time.

Also, just for clarity, there are 3 types of Regens: Passive, Active and Parked.

Passive: Driving down the road, normal engine operation creates high exhaust temps that burn off some soot from the DPF.

Active: During driving the system will use the turbo and additional fuel injected into the exhaust to raise DPF temps high enough to (nearly) completely burn off any soot. This type is also subject to operating conditions.

Parked: Just like an Active regen, however this is performed while stationary (IE: under a controlled environment). Usually only needed when the first 2 types have repeatedly been unable to bring the soot levels below a preprogrammed threshold and the computer determines that continued operation risks an unsafe level of exhaust restriction.

Passive regens happen completely without your knowledge. Active regens can also be hard to spot when driving down the highway. Passive regens need good hard pulls to produce hotter exhaust gasses and be effective. Active regens use the turbo and doser valve to force the exhaust gasses to be hotter. Both types are only effective if they can run successfully for about 45 minutes to and hour without interruption.

I'm assuming the issue is that you're being asked by the computer to perform parked regens to clean the system. Which means that Active or Passive regens aren't completing properly. While the EGR valve does play a role, it's probably NOT the cause of your issues if a Parked regen works. In addition to the sensors listed above you should look for exhaust leaks. They have a smaller impact on parked regens and can completely throw off any regen attempts. Also, depending on the age, you might just need a new DOC. The coating of precious metals wears away over time and eventually doesn't produce a good enough chemical reaction to sustain a successful regen cycle.

What kind of driving do you do? OTR? Local? Mostly highway or a lot of stop and go? Do you have a Pyro gauge? Maybe you're driving habits or route isn't conducive to successful passive/active regens.

Also, what has your oil consumption been since the rebuild? You could still be burning excess oil while the piston rings set, leading to extra soot clogging up the DPF and EGR systems.