Jim,
You are a very tech savvy guy. I have used a data logger to help diagnose intermittent behavior. I used one like this to figure out what was shutting down my Aquahot mid cycle.
https://www.dataq.com/data-logger/
I have one of their products but there are plenty of suppliers.
Richard, I'll look into that. Just arrived at homebase and have a project which is testing my endurance or lack thereof. Never thought I would be hanging drywall in my 7th decade but I do enjoy the camaraderie of my "Superintendent" who has a 35 year history with me.
God Bless you Jim. That's awesome! (Not that I want to be in your position today to hang drywall!) It is really surprising what we can do when we least expect it. Keeps us young. (Wish my brain stayed that way...)
"SOLVED" I think! Tracing the DEF Line Heater wiring a single orange wire runs from the Rear Load Center and is spliced to all 3 DEF Line Heaters EXACTLY centered over a frame rail above the tag steering accumulator. I could barely touch it and ran my bore scope in there to see how it was assembled. I decided to cut the splice out & look what I found. The splice was the 3 DEF Heater wires twisted together with the power wire laid on them and a drop of solder to make the connection. Cold solder joint on 3 the strands of the power wire, the remaining strands were not attached in any way, and NO mechanical connection. It was all held together with shrink tubing.
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Nice job on that, considering the difficulty working in such a confined area. It's really tight under there and tracing wires is going to test anyone's best efforts. That wire connection, if it was done by Newell is really disappointing.
(09-25-2023, 06:13 AM)RobSC Wrote: [ -> ]Nice job on that, considering the difficulty working in such a confined area. It's really tight under there and tracing wires is going to test anyone's best efforts. That wire connection, if it was done by Newell is really disappointing.
Thanks Rob, I started another thread on Solder Sleeves to see what others are thinking. I wonder how many other Solder Sleeves are lurking inside wiring looms waiting for an opportunity to drive us crazy with intermittent problems.
I'm getting my notes together to post a complete report.
HURRRRRAYYYYY!!!!! NICE JOB!!!!
Those joints (a drop of solder) DISGUST ME!! And will probably put Simon over the edge! LOL
As to the Solder Sleeves, those sure are awesome…in theory. I just don’t have any empirical knowledge for you; again, perhaps Simon has used them.
I’m sure most of us are the traditional HEAT THE CRAP OUTTA BOTH SIDES and LAY A LINE A SOLDER kinda guys. But, admittedly, I’m now pretty much a fan of using high quality crimps WITH waterproof adhesive shrink.
I’d say that the entire newer coaches are nothing but crimps, but I sure wish they were all the waterproof style!!
Jim, that is awesome! I know you’ve been battling this mystery for a while. Glad you found it!
I have found many splices like that however with no solder. Just wires wrapped together and black taped. Some if not most splices had the single sided butt crimp in which not all wires were securely fastened.
Here is a heater branch circuit that was hidden behind cove molding. I am a believer in solder and have soldered every connection I could get my hands on. Resistance is futile!
I have not used the low temp solder thingamabobs. They have their place but I only trust a normal old fashioned soldering iron joint and non adhesive heat shrink tubing. To each to their own. One thing I teach my guys when wiring devices is to always use the screw terminals and never tighten said screw with a cordless tool. Always by hand. We only use Wago connectors when changing ballasts and making emergency repairs. Alumiconn connectors to join aluminum to copper.
Every method has its place. Many ways to get to point B from A
I added about 18" of wire and used butt connectors. I have to keep an open mind as I assume I found the problem but cannot guarantee that bad splice was the only problem. Time will tell. I am posting a copy of my notes for reference.
Thanks everyone for your insights and help.
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Torque Derate Sequence of Events
For a failed UQS sensor, the ECM will impose the following inducement strategy. When the ECM recognizes the issue with the sensor the check engine light will illuminate for one hour with no engine power derate. After one hour, a 25% derate will be applied for four hours, unless the issue is resolved. In that case, engine power will be immediately restored. If the issue is not resolved within 5 hours of the check engine light coming on, a 40% power derate will be ramped in until the ECM determines it is safe to limit the truck to 5 mph. At this stage, if the fault goes inactive, the ECM will be “sensitive” to SCR faults. For the next 40 hours, after vehicle speed has been restored, any SCR tampering fault will send the truck immediately back to a 25% derate and starts the cycle over again. However, after 40 hours of no active faults, the timer will be reset, and all will be good.
The 5-mph limit will not be applied until the ECM finds it safe to restrict vehicle speed. The truck will not immediately reduce speed to 5 mph on the highway, even if the timer threshold has been met. The ECM would need to see an extended idle time, a key cycle, or a fuel refill to apply the 5-mph limit. With an EGR or SCR system fault that is not a UQS or non-circuit error SCR system fault, only torque derate 1 will be enforced. A circuit error such as a disconnected tank sensor, def pump, NOx sensor, tank heater, or dosing valve will result in an SCR system tampering condition. A tampering condition will follow the warning, derate 1, derate 2, and severe derate process.
I just added Adobe .pdf files for those who don't have Word