King Control Repair
I received my King Control from Brent Delfel of Advanced Diagnostics Consulting in Snohomish, WA. this past Friday, Feb. 7, 2025. It is now installed and I have taken it on a 30 mile test drive where I tested throttle, cruise, and transmission performance. Everything is now working as designed including the idle step up.
It's my understanding that the King Control was installed by Foretravel on the Cummins C8.3 (1996 to early 1998) in U270s and many U295s. This engine has the 12 valve all mechanical Bosch P Pump without a computer and was the RV/Fire Engine version with 315 to 325 HP. It was also installed on other motorhomes and commercial trucks with a similar non computerized engine. My engine does have the Allison 3060R transmission which requires a TPS signal for proper shifting. Earlier C8.3 engines had an air throttle, Allison TPS, and Bendix cruise control (now obsolete). This early drive by wire system uses an accelerator position sensor at the go pedal that sends information to the King Control that has a built in TPS that speaks to the Allison 3060R. The cruise control operates from the Smart Wheel and is part of the King Control and does not require information from the APS at the go pedal.
The King Control system can fail in multiple ways: You can lose the throttle portion; the TPS; the APS; the cruise function; and various combinations of the above. There can be a failure of the stepper motor, in which case you lose throttle and cruise, along with the normal stuff of bad connections, broken belts, etc. My failure was at the connection to the board that eventually took out throttle and cruise, but not TPS. My repair included connections and a new "old stock" motherboard. Repair of the motherboard was an option, but I decided to take advantage of a "new" motherboard hoping that this repair would take me to the end of my use of the motorhome.
The diagnostic information posted in a previous thread helped me narrow my problem down. I sent a photo of the King Control with the cover off to Brent and he immediately saw burnt contacts, which when I tried to re-seat them started crumbling and I lost cruise control in addition to the original loss of throttle response.
You have two options.
A: Convert to air throttle, a stand alone Allison TPS, and a stand alone cruise. The ground work for this conversion has been pioneered by a member of the forum and he has manufactured a handy mounting plate for the three control cables and has extensive written instructions available along with photos. Contact Charles at CRY42@windstream.net.
B: Run through the trouble shooting guide for the King Control and if it appears your control is defective open up the control box, take a few good pictures and contact Brent Defel at AdvancedDiagnosticConsulting@gmail.com. He's a good communicator and returns voice mails (501-500-3611) and emails. This is not his primary business but he is working to put together a compete rebuild and testing procedure together. PS. If you send your King Control to him (prior approval required) make sure you tell the UPS clerk not to require a signature. I didn't know that was the default at some UPS stores.
Neither option is cheap or fast. I've been down for two months. Dub here on the forum went with an air throttle, TPS, and managed to keep the King Control as his cruise control. I was fortunate to get back home to our lot at the SKP Ranch Coop here in southeast NM. I've been using my down time to service the transmission, hydraulic filters, replace an idler pully, repair some fiberglass damage, and get caught up on paperwork. We did miss Quartzsite.
My experience and that of others suggests that most of the time there are signs of a pending throttle problem. You will probably change a few fuel filters along the way as it can be hard to know the difference. You may pull over for the night or a few minutes and it will start working normally. You may change your filters and think "Aha," problem solved. If that happens more than once I suggest putting together an emergency throttle kit, unbolt the King Control and turn it on its side to remove the six screws holding the cover down. Get a good flashlight and look closely at the connections and then start trouble shooting as per the instructions. Burnt connections are not your friend.
Topic: King Control Repair