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Weird high idle

1042 Views 15 Replies 4 Participants Last post by  Cummins_freak777
Ok so i was driving back home tonight and noticed that my truck had itself idled up to 1000rpm even though the truck was at op temp. It was 39 degrees out so a little chilly but nothing too serious. I recently installed an edge drag comp and the truck would run the same idle speed with the chip on and off. Bumping the throttle also did nothing to brig it down either. I had a smarty on the truck before this and last winter it would high idle but it would idle faster and i could just bump the throttle to make it go down. Im kinda confused any of yall got suggestions?
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if i shut the truck off and restart it the idle returns to normal
Oh... I hate to say it but that is slightly leaning towards a ECM issue? (Maybe) So do you have any error codes? Could you get a hold of a live data tool and verify the TPS signal and its working properly? You didn't adjust the APPS voltage did you?
The fact you shut down the truck (reseting the ECM) and starting (rebooting the ECM) and getting a different idle worries me.
Once again we are going to have to do some testing. To rule out the APPS sensor I need to know if you have OE APPS or a Timbo's APPS? If its a Timbo's you need to adjust according to Tmbo's installation. If its a OE APPS check the voltage and make sure its UNDER the tag voltage. If so leave alone.

Again double check error codes. See if any APPS codes are present.

After thinking about it a bit it was really common for people to adjust their APPS voltage trying to hit th tag voltage and presto have a slightly high idle because the IVS (Idle Validation switch) was toggled for throttling and it followed APPS voltage. But if the IVS was ground for idle then it would be following ECM idle software and ignoring APPS voltage. So that being said and if you have OE APPS this is all possible...
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