Supplemental heater
Cargo Master
Joined: May 2007
Posts: 3,336
Likes: 4
From: Western New York
I think its normal your 7.3 does that. Even the 6.7L will do that to an extent.
The high idle switch (up through 2016) was basically hooking up a specific-value Radio Shack resistor between a specific blunt-cut wire in the bundle under the dash, and one of the upfitter switches. The value of the resistor would change the idle RPM of the truck. Some people wired in a rheostat so they could vary idle speed any time the switch was turned on. Basically, while in Park with the parking brake engaged, flip the upfitter switch and the truck would idle up. It was useful for cold-weather warm up, or longer periods of idling. Idling at a higher RPM uses more fuel, but is better for the engine and reduces DPF build up a little bit.
I'm not sure how to do it yet on the 2017's, but there is quite the write-ups on this forum for the 6.7's and I think even the 6.4's. Just do a search if you have further interest.
The high idle switch (up through 2016) was basically hooking up a specific-value Radio Shack resistor between a specific blunt-cut wire in the bundle under the dash, and one of the upfitter switches. The value of the resistor would change the idle RPM of the truck. Some people wired in a rheostat so they could vary idle speed any time the switch was turned on. Basically, while in Park with the parking brake engaged, flip the upfitter switch and the truck would idle up. It was useful for cold-weather warm up, or longer periods of idling. Idling at a higher RPM uses more fuel, but is better for the engine and reduces DPF build up a little bit.
I'm not sure how to do it yet on the 2017's, but there is quite the write-ups on this forum for the 6.7's and I think even the 6.4's. Just do a search if you have further interest.
Hotshot
Joined: Apr 2013
Posts: 10,121
Likes: 654
From: NH
This is a mod I might do if the rpm's don't run up automatically. My 7.3 idles up to 1050 rpms when cold and cuts back at the same time as the waste gate opens back up, or if any of the operating controls are touched, including the brake. The remote start will crank it up to low idle for about a minute and then the high idle kicks in as designed from the factory. Snow starts melting in about 10 minutes with 15 degrees or higher temps. The system works well with no outside idle control necessary. In the extreme cold if the coolant temp falls off it will automatically idle back up until enough heat is returned to the system. Diesels will cool off dramatically at regular idle by push a lot of heat with a few hundred extra rip ems.
To be perfectly honest, it's been awhile since last winter, and all the diesel 6.7's I've had came with the supplemental heater due to the state I live in.
All I remember is even with the supplemental heater, the gas trucks warmed up quicker.
Cargo Master
Joined: May 2007
Posts: 3,336
Likes: 4
From: Western New York
The 6.7L does idle higher when cold, but not as high as the high idle switch will provide.
To be perfectly honest, it's been awhile since last winter, and all the diesel 6.7's I've had came with the supplemental heater due to the state I live in.
All I remember is even with the supplemental heater, the gas trucks warmed up quicker.
To be perfectly honest, it's been awhile since last winter, and all the diesel 6.7's I've had came with the supplemental heater due to the state I live in.
All I remember is even with the supplemental heater, the gas trucks warmed up quicker.
Senior User
Joined: Oct 2016
Posts: 135
Likes: 1
Hmmmm....buy my truck in CO, get block heat and supp heat for free. Visit my Dad while I'm there. Drive back to OK and break-in is complete and ready to tow??? Sounds like a win for me.
BTW, this is exactly what I did when I bought my Subaru. Best price was is in Denver plus they gave me a $400 credit for my plane ticket. Picked me up at the airport, I was at the dealer for literally 20 minutes, drove my car back home and paid the tax required here in OK. Sweet deal.
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agpopp
6.7L Power Stroke Diesel
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Oct 19, 2018 03:16 PM
