2014 Kenworth T680 Mx Paccar

Wow, 10 thousand dollars and it sounds like a lot of guess work to get there. I hope everything is fixed correctly. Every time I start thinking about buying a newer truck I read a post like this and figure a old truck if good enough. I wish you good luck.

 

More of a EPA2010 guy (big difference) but there are a few items I find questionable and some computer (DAVIE) staples and techniques (Verification Cycle) that are the same across the board. The BPV valve and BPV position sensor are 2 different items, the valve itself is costly but plenty robust and haven't personally seen any problems other than a small air leak during regen at the internal "butterfly valve" arm attach point where the sensor actuator rod end attaches. On EPA2010 the sensor is air operated/computer controlled, normally what fails is the rod end ball joint itself (replaced a few), once this occurs the valve isn't opening and closing completely as initially calibrated for regen AND normal operation, generating codes. DAVIE computer is quit extensive on "Initialization" and "Calibration" functions (IF USED), the bellows pipe is pretty stout itself so I question the removal technique (if it was just the sensor, none of this would have been necessary) but I wasn't there. Now the fuel doser's do fail but are also designed to be partially removed, cleaned and re-installed with a new gasket and isolater pad for optimum performance but again DAVIE allows for testing this item directly with the exhaust removed, engine running and a way to measure the amount of fuel and quality of spray (should be atomized to the point of looking like smoke and not dribbling fuel).The "pressure valve" you speak of could be several things; EGR pressure differential sensor or the DPF pressure differential sensor which is a common code but not usually the sensor itself, either the venturi or tubing or DPF is clogged enough for these to generate codes and or possibly a simple "flag" that's telling you "I NEED A COMPLETE REGEN ASAP". Since I have access to a davie, I try NOT to react to every code that comes down the pike because you'll lose your mind. I try to clear everything, do a regen, and concentrate on what comes back (I take pictures before and after). Now I can attest to the ACM's not being as bullet proof as they should be (long story), when things start NOT making sense to me I also have the luxury of pulling a "sistership" ACM and temporarily hook up to the truck I'm having problems with, this has corrected most all unusual problems (especially J1939 communication), I do check wiring and connections first before I've replaced or sent even a NEW one back for warranty. Now the last issue that grinds me about any shop repairs are "Who Decides" how long something should take and have the gall to put it in a book. I'm not 20 anymore but I want to believe I'm allot smarter now than I was then (59 now). Some things are straight forward; "change bulb", some are not so easy and need some research, the one's I like are the one's no one wants to touch, you have to stay focused and constantly review whats BEEN done already and what needs to be done "next". I say pfft!, I'm done when it's done. Time limits quality every way, shape or form and is inherently a bad way to operate a successful business (I always stand my ground)...just MY opinion and thoughts, thanks.

 

(Thanksgiving-Saturday)...after some beauty sleep (I need lots), I've re-read my post and didn't quite answer your question(s) so I want to summarize a bit to maybe your benefit. On one hand some things just don't go like "clockwork", I feel for the mechanic, on the other, if he's done things that needed approval and didn't follow set policy, this might work to your advantage when the bill is tallied with proper management (midnight out the door doesn't seem right anyway).The important part is that the truck is operating correctly. I would ask if I could run it down the road a bit before handing over the check (20 miles out, 20 back, highway). What I failed to mention previously was a "Verification Cycle" that needs to be completed prior to release and that every owner of an MX should be aware of. Depending upon the repair, this can be a factor on recurring codes and confusing even the most adept shops and mechanics because of the extra time involved, its almost always overlooked.

 

First time I tried to upload a file, somebody please tell if I did this correctly or just unloaded my whole laptop....OOOPS.

 

Did it correct @JohnC123 on the upload! Many times on newer engines that are OBD compliment the hard part is duplicating the condition when the fault is set and verifying that the repair is complete. Troubleshooting is a skill that takes many years to perfect, yet you always get a "tough" one that wants to defeat you. Latest software in PMCI or ACM in a Paccar is a must, and hardware issues tend to be very tough to isolate.
Hopefully you are up and running without issues. I am sure the service department will work with you if you politely voice your frustrations and discuss the whole diagnosis and repair making sure proper protocol was followed.

 

Thanks.... just got in (home) and was worried thatI gave me life away. Thank you, thank you, thankyou!

 

Normally on the MX engine from what i seen with my less then 1 year experience working on this engine...that BPV code is either the BP sensor or the harness. The entire engine harness doesn't need to be replaced because a lot of components would need to be removed, but someone with good electrical wiring experience can run a overlay from the ecm to the wire that needs to be repaired on the BP pigtail.

 

Your absolutely correct on a "hard failure", the BPV valve itself is purely mechanical in a nutshell, but he's all over the board on this on and the position sensor came up at the beginning, then bloomed into a "storm", There are 3 harnesses; Connector "A" contains injectors, pumps and engine brake, "B" is the cab interface and "C" is all the hardwired sensors. In a "moment", I can think of a number of things that I would have done differently but that's me and we're all here to help. I will say this; Paccar is very proprietary and if you have any experience with the "new" stuff, welcome aboard...thanks.