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Discussion Starter · #1 ·
On my 02 I am having a problem with my high idle. I'll start the truck, and it'll start to increase the idle. Right as it gets to the peak of the high idle it sounds like a couple of injectors shut off and it starts making quite a racket and runs like crap. As soon as you hit the brake it'll idle normally and you can press the accelerator and it runs fine throughout the entire rpm range, it is only when the high idle kicks in. Anyone have anythoughts? Even if I sit in the truck and hold the accelerator at the same RPM as high idle it runs fine, it is only when the computer automatically does it.

Thanks,
Josh
 

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On my 02 I am having a problem with my high idle. I'll start the truck, and it'll start to increase the idle. Right as it gets to the peak of the high idle it sounds like a couple of injectors shut off and it starts making quite a racket and runs like crap. As soon as you hit the brake it'll idle normally and you can press the accelerator and it runs fine throughout the entire rpm range, it is only when the high idle kicks in. Anyone have anythoughts? Even if I sit in the truck and hold the accelerator at the same RPM as high idle it runs fine, it is only when the computer automatically does it.

Thanks,
Josh
Sounds like your high idle is working correctly. When it kicks in, it will only be running on three cylinders. So your assumption that some of the injectors shutting down is correct, and it will sound really weird. Hitting the brake is one of the triggers that turn the high idle off, same if you put your truck in gear, or start moving.
 

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Discussion Starter · #3 ·
Understandably, but I have had this truck for 5 years, and the truck never has sounded like this during high idle, it used to sound the same as if I held the accelerator pedal to 1200 RPMs. Now the sound gets 10 to 15 times louder and it really doesn't sound good. Scared the crap out of me the first time it happened and I shut the truck off right away to make sure I didn't have pistons poping out of the valve cover or the crankshaft laying on the ground.
 

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Discussion Starter · #5 ·
I'll check when I get home, youtube is blocked at work, and I'll try to upload a sound clip of it. Thanks for the help.
 

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Rescue Tower
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It's 3cyl high idle. Occurs when the coolant (ECT) is less than 140 degrees and the AIT is less than 15 degrees. That's why you've never heard it before. I installed a switch to manually start high idle and 3cyl high idle.
 

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Discussion Starter · #7 ·
It's 3cyl high idle. Occurs when the coolant (ECT) is less than 140 degrees and the AIT is less than 15 degrees. That's why you've never heard it before.

You're right, have had the truck for 5 years in Colorado, never have heard high idle before :hehe:
 

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Diesel Filled Veins!
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There is two parts to the high idle. The first is idling at 1200rpm when the incoming air is around 0*C. Around -9*C the second part kicks in and you get high idle with 3 cylinders firing aka 3 cylinder high idle. Check out The Mopar1973Man Site And Forum for more info and how to wire up some switches so you can have both high idle and high idle with 3 cylinder mode any time you want.
 

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Discussion Starter · #9 ·
Well, I think I may have some PCM or sensor problems. It was 27degrees last night and it went into 3cyl idle, and the previous times have all been above 20degrees as well. Before this fall, it has never gone into 3cyl idle, and I have had this thing frozen before, like snowmobiling in Wyoming for 2 days with the temp being -25 and the truck hadn't run in two days. So who knows why it decided to start working now, and the normal high idle isn't. Oh well, if its not harmful on the engine I am not going to worry about it until other problems arise. I have a buddy with a scanner and next time its convenient I'll have him hook up to it to see what the IAT is saying, my guess is that is what is faulty.

Thanks for the help.

Josh
 

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Mopar1973Man.Com
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Updated Video...

Nice to have full control... :headbang:
 

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^^^+1:thumbsup:
 

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Just Another Slow VP
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i wish i had high/3cyl idle and yer high idle bomb mike!!:drool2::drool2:
 

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Mopar1973Man.Com
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i wish i had high/3cyl idle and yer high idle bomb mike!!:drool2::drool2:
Well barrow a Smarty and play with for a hour and return to stock (free high idle software). Then build the high idle mod and you good to go...

Like this morning I went out and flip #2 switch and high idled till 100*F coolant temp on the SG II and left the house for work. By the time I travelled 4-5 miles I had 160*F of coolant, heat in the cab and it was only 28*F this morning here... Unplugged and sitting cold... :whip:
 

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So the high idle and 3 cylinder high idle is done via a Smarty?
 

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Just Another Slow VP
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well thats just it i cant find anyone with a smarty:banghead::banghead:

or else id have it all done and runnin by now:lol4:

can be done with a smarty or by going to a dealer
 

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Well barrow a Smarty and play with for a hour and return to stock (free high idle software). Then build the high idle mod and you good to go...

Like this morning I went out and flip #2 switch and high idled till 100*F coolant temp on the SG II and left the house for work. By the time I travelled 4-5 miles I had 160*F of coolant, heat in the cab and it was only 28*F this morning here... Unplugged and sitting cold... :whip:
once its turned on by the Smarty it cant be turned off by the Smarty:banghead:
 

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Mopar1973Man.Com
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once its turned on by the Smarty it cant be turned off by the Smarty:banghead:
Why would you want to turn it off??? :confused013:
 
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