ryan88210

does the newer 6.7's come with high idle? is that what the cruise control switch does while idling? what is the purpose of this if the 6.7's arent supposed to be idled for to long? and lastly is it supposed to be used in cold conditions? thanks

sabersix

Well, if no one else is going to chime in...

The 6.7L will go to high idle (1100 rpm fixed) automatically based on engine temperature. There is also a manually activated high idle (1000-1600 rpm) that is controlled via the cruise control buttons. This feature must be activated by your dealer.

The latest ECM flashes have changed the behavior of the 6.7L engine's regeneration cycle to compensate for extended idling. The engine will automatically raise the idle and go through regeneration while at idle.

Onelongshot

Engine Idling
Avoid prolonged idling, long periods of idling may be
harmful to your engine because combustion chamber
temperatures can drop so low that the fuel may not burn
completely. Incomplete combustion allows carbon and
varnish to form on piston rings and injector nozzles.
Also, the unburned fuel can enter the crankcase, diluting
the oil and causing rapid wear to the engine.

CAUTION!
Extended periods of idle time may not allow the
vehicle’s exhaust aftertreatment system to properly
regenerate. This can lead to the illumination of the
Malfunction Indicator Light (MIL) or an Electronic
Vehicle Information Center (EVIC) warning message.
Operating the engine for extended periods with the
MIL illuminated or an EVIC warning message displayed
can cause extensive engine and exhaust system
damage.

NOTE: Your vehicle is equipped with a turbo speed
limiter, this feature limits the engine speed to 1200 rpm
when engine coolant temperatures are below 70°F (21°C).
This feature is designed to protect the turbo charger from
damage and will only operate in PARK or NEUTRAL.

NOTE: An optional driver-controlled high idle speed is
available on automatic transmission equipped vehicles
with speed control. This feature allows the driver to
select an elevated idle speed between 1100 and 1500
rpms. Your dealer can enable this feature.
The optional driver-controlled high idle speed will help
increase cylinder temperatures and provide additional
cab heat, however, may still cause the exhaust aftertreatment
system to not properly regenerate. Extended periods
of idle time should be avoided.
NOTE:
² If ambient temperatures are low and the coolant
temperature is below 200°F (93°C), the engine idle
speed will slowly increase to 1000 RPM after 2 minutes
of idle, if the following conditions are met:
² foot is off brake pedal and throttle pedal
² automatic transmission is in Park (P)
² vehicle speed is zero
² Applying the throttle will cancel fast idle
² If the engine is equipped with an exhaust brake,
operating the exhaust brake at idle will greatly improve
warm up rate and will help keep the engine
close to operating temperature during extended idle.

Hounddog

Idle is considered under 1000 rpm.That's WHY there is a high idle you can activate and turn on and off.Ramp it to 1200/1500 high idle and let it hum for whatever how long.

Diesel fitter

Is this high idle feature also on the 6 spd manual transmission modles?? Does this also have the 3 cyl feature like my '02 has??

sabersix

It is available for manual transmission, but requires a jumper wire (brake switch wiring, I believe).

No, not 3 cylinder.

titoheadfaceman

let your truck idle normally, then press the cruise control on button, then the set button. RPM should rise. You can also make it a little faster by hitting the accelerate button. This is all of course if you have a 68RFE or the AISIN

mastercaster

wow, just do a search for high idle 6.7! it can be done easily on either an automatic or manual tranny. look through my posts if you like.