High Idle after W.O.T.

[BigTruck_Srt10]

Normally my truck idles at 800 rpms, however after a pass under boost my trucks idle will stay around 11-1300 rpms when I come to a stop then eventually come down to 800. Takes a good 30 seconds or so to drop down and will not repeat if I restart the truck. It then idles normally coming to a stop. Was told to check for a vacuum leaks, everything checked out ok. Any Idea's?

Thanks Guys,

Mods: Built Bottom End, Roe S/C, AEM Meth kit, SCT Tuned.

 

[VENOMOUS1 RACING]

Normally my truck idles at 800 rpms, however after a pass under boost my trucks idle will stay around 11-1300 rpms when I come to a stop then eventually come down to 800. Takes a good 30 seconds or so to drop down and will not repeat if I restart the truck. It then idles normally coming to a stop. Was told to check for a vacuum leaks, everything checked out ok. Any Idea's?

Thanks Guys,

Mods: Built Bottom End, Roe S/C, AEM Meth kit, SCT Tuned.

Yessir check for vacuum leaks for sure. Clean your IAC valve and if all else fails time for a new TPS. Try tapping gas pedal couple times next time it does it and see if it doesn't come down. What kind of TB? Roe as well?

 

[VENOMOUS1 RACING]

Oh and are you ready for a GTG/Cruise soon? :rock:

 

[SRT10VENOMOUS]

My IAC did the exact thing, the plunger would move but to slowly it was all gummed up , i just bought a new one and she works perfectly now

 

[BigTruck_Srt10]

Thanks Fellas, i'll change it as soon as I get a chance. Venomous I'm ready, just point me in the direction of the details. The truck was down since March so she's ready to stretch her legs. 1200 miles on the motor she's ready to go. And yes sir, roe TB as well.

 

[vprtech]

Thanks Fellas, i'll change it as soon as I get a chance. Venomous I'm ready, just point me in the direction of the details. The truck was down since March so she's ready to stretch her legs. 1200 miles on the motor she's ready to go. And yes sir, roe TB as well.

So the Viper truck ecu (aka JTEC) has special adaptive values that change to help ecu control the idle, and return to idle nicely. The ecu can adapt to a certain point, if it cannot adapt properly, the side affects can be idle hang or idle dip when releasing the throttle. For the ecu to learn these adaptive values, it must run until fully warmed up (oil and coolant), and then idled for several minuets with the A/C off, and then the A/C on. If you continue to have idle issues, try the idle learn that I outlined. This will need to be re-done whenever the battery is disconnected because the adaptive values are stored in volatile memory, or keep alive memory. If you continue to have problems then tuning changes will need to be made.

 

[VENOMOUS1 RACING]

So the Viper truck ecu (aka JTEC) has special adaptive values that change to help ecu control the idle, and return to idle nicely. The ecu can adapt to a certain point, if it cannot adapt properly, the side affects can be idle hang or idle dip when releasing the throttle. For the ecu to learn these adaptive values, it must run until fully warmed up (oil and coolant), and then idled for several minuets with the A/C off, and then the A/C on. If you continue to have idle issues, try the idle learn that I outlined. This will need to be re-done whenever the battery is disconnected because the adaptive values are stored in volatile memory, or keep alive memory. If you continue to have problems then tuning changes will need to be made.

Very good info. Especially in heavily Cammed engines and I could see FI having the same issue but opposite of cam needing more idle air to stay within IAC correction ability the SC could produce too much idle air for the IAC to correct for.
If its a new problem is say its likely dirty IAC or bad IAC. Our trucks do eat TPS as well as most Mopar of our era, lol.
Great to see you post sir.