Can someone expain this to me. Is this a stock featue or is it something thats added aftermarket. I'm thinking about the Smarty Jr and it mentions 3 cyl high idle. What is this????

Thanks

 

There is no 3 cylinder idle on 3rd Gen engines only 2nd Gen engines have it.

 

There are 2 different types of high idle features. First everyone has the AUTO high idle feature, when the temp is cold enough the idle will ramp up to 1000rpms on its own and stay there until you touch brake or the go pedal. And it will return to 750rpms when it senses temp of coolant and air intake is warm enough. If its only cool and not cold, it will idle up to 1000rpms on its own after about 2 minutes.
Second feature is the manual high idle which is controlled through the cruise control buttons. It can be turn on at any time regardless of outside temp or motor temp. Turn cruise on, press set button, engine revs to 1100prms, you can increase/decrease rpms from 1100 to 1500 rpms using the acel and resume buttons. touching the brake or go pedal will return the engine back to 750rpms. Late 03-04 trucks need to have a TSB applied and then the feature needs to be enabled - 04.5 and up trucks just need the feature enabled by the dealer(some will charge you for this).
If truck has vaccum controlled cruise it will not work, 03 and some 04 trucks I think. Also for a manual tranny there other things that need to done before using the feature.
Smarty Jr does not turn this feature on, don't know about the Smarty Sr.

 

according to the Smarty Jr. description at the DTR store there is:
http://store.dieseltruckresource.com/smjr03do.html

from what I've gathered, all 3 cylinder high idle does is disable the injectos on 3 cylinders which makes it sound awful and supposedly warms the engine faster since 3 cylinders are being dragged along by the others keeping the EGT's higher.

 

When that 3 cylinder idle kicks in on my 2nd gen, it sounds like a rod is going to come out the side of the block (well, more of a rod than usual). Sure does warm up nicely though, egt's sit at about 625 vs the 300 or the regular high idle.

 

I know what is said on the web page and why I emailed Smarty directly to ask about enabling the 3 cylinder high idle for 3rd gen trucks. The reply from Smarty was NO the 3 cylinder high idle option/feature can not be turned on for 3rd Gen trucks, only 2nd Gen trucks and that is why I posted what I did above.

 

I had the 3 cyl idle cut in on my previous truck (a 2002) - but only when it was extremely cold (-45*). The EGT dropped to about 150*, but the engine temp came up. It sounded like the egine was full of rocks the size of your fist! Worked like a darn though.