any one know to fix high idle problem?

[MO K]

Anyone know why this is happening? I have a 2007 gt500 that doesn’t return to idle
when I rev it. I tap the gas, the rpms go to 3,500 and don’t come down.
Now normal driving is impossible.
The throttle body sensor and actuator have already been replaced, but nothing has changed.

here are error code
P0720 Output Shaft Speed Sensor Circuit [GM/GMLAN]
P0722 Output Shaft Speed Sensor Circuit No Signal [GM/GMLAN]
P2104 Throttle Actuator Control System - Forced Idle [All Manufacturers/Standard]
P2111 Throttle Actuator A Control System - Stuck Open [GM/GMLAN]

I disassembled the throttlebody actuator and it moved smoothly without any pinching. But I'm no expert, so I can't say for sure that the throttle body isn't the problem.


2007 Shelby GT500
kenebelle 2.8L / 2.875" pulley / MAFia / 5" inlet / 75mmDual TB / FIC 1000cc Injectors / AFCO Dual Heat Exchanger / 90mm Idler pulley / VMP Tune / EGR Delete

 

[Vinnie_B]

First thing you should do is scan your car for any DTC'S.



You can also check the following:

• Check for air leaks, including proper sealing of intake manifold and components/vacuum lines attached to intake air (such as the PCV, EGR or IAC valve/vacuum lines).
• Verify the engine operates at normal temperature.
• Fast idle concerns (for vehicles equipped with an IAC valve) With the key ON, engine OFF monitor the TP MODE PID while wiggling the TP sensor circuits. The TP MODE PID can also be monitored during vehicle drive. With the throttle closed, the TP MODE PID must be C/T (closed throttle).
• Intake Air System Leaks

 

[MO K]

Thank you for answer. I added information to my first post.

 

[Vinnie_B]

P0720 and P0722 are Output Shaft Speed (OSS )related

Possible issues could be:

• OSS sensor circuit short to GND
• OSS sensor circuit short to PWR
• OSS sensor circuit open
• Damaged OSS sensor
• Damaged OSS connector
• Damaged OSS sensor, or not installed properly
• Harness intermittently shorted or open

P02104 and P0211 are Throttle Actuator Control (TAC) related

P02104 DTC is an informational DTC and may be set in combination with a number of other DTCs which are causing the FMEM (failure mode effects management) *Mode of forced idle. Diagnose other DTCs first.

P0211 is set when the powertrain control module (PCM) fault status indicates the throttle plate is at a greater angle than commanded

Possible issue could be:

• Binding throttle body, stuck open
• TAC motor circuits are cross-wired
• TAC motor harness circuits are shorted together
• Damaged PCM

Lightning FastElectrical Automotive Repair
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[claybeatz]

Check the spring on the throttle body, make sure it snaps shut by itself when you open the blades and let go

 

[einehund]

Anyone around you with a different TB that you could just swap to test? I remember hearing something a while ago about KB TBs. Not sure if it still applies, but it may be worth a shot.

 

[Robert M]

Kenne Bell has a tune update for this issue, and there are also some T.B. updates that they have for the Dual/Twin 75mm.........Contact Kenne Bell.

If you "borrow" another T.B. and it does not have the K.B. updates, you may experience the same thing as you have now.......and be chasing your tail........

How old is your Kenne Bell tune and what version is your Dual/Twin 75mm T.B.? The version, if it is a newer T.B. is stamped on the backside on the mounting surface, the very early Twin 75's have no version stamp. That would be the starting point to trouble shoot?

The original 2.8 KB 725 tune updates to 750 with the updated tune, and requires a Gimme 5 CAI and if you have the Diablo MAFia, original 725 stuff, that also gets deleted with the new 750 tune and Gimme 5 install.........

R

 

[VNMOUS1]

OSS Sensor. If it's screwed up the vehicle will get conflicting information as to the status (still, moving, how fast).

That can cause your problem

Sent from my SM-N986U1 using Tapatalk

 

[Robert M]

OSS Sensor. If it's screwed up the vehicle will get conflicting information as to the status (still, moving, how fast).

That can cause your problem

Sent from my SM-N986U1 using Tapatalk

^^^^^^To add to this reply..............Yes, it may not be a "Kenne Bell" fix, when my 2.8 725 had this "hanging idle" problem, 1200-1500 rpm when the clutch was pushed in, I had no error codes and I will also mention mine did not do it every time I came to a stop and pushed the clutch in, just occasionally would it happen, but it was annoying to pull up to a stop light, push the clutch in and the engine stay revving at 1200-1500.

R

 

[MO K]

The repair shop couldn't find the cause, so the opinion was to just replace the throttle body, and to restore the custom tune to its original state. I could instinctively know that it was not the right answer,
Then, among your replies on the forum, the problem was solved after replacing the throttle body. focused on opinions.
So I checked the throttle position sensor voltage at idle.
Voltage was measured at V1.76 and the adjusting screw was also loose! So, I searched the factory setting and adjusted it to V1.23 and fixed the adjusting screw. And the problem was solved. Good luck, and thank you. Let's all ride the 5th generation GT500 for a long, long time.

 

[Robert M]

The repair shop couldn't find the cause, so the opinion was to just replace the throttle body, and to restore the custom tune to its original state. I could instinctively know that it was not the right answer,
Then, among your replies on the forum, the problem was solved after replacing the throttle body. focused on opinions.
So I checked the throttle position sensor voltage at idle.
Voltage was measured at V1.76 and the adjusting screw was also loose! So, I searched the factory setting and adjusted it to V1.23 and fixed the adjusting screw. And the problem was solved. Good luck, and thank you. Let's all ride the 5th generation GT500 for a long, long time.

You mentioned in your original post................"The throttle body sensor and actuator have already been replaced, but nothing has changed." <<Did you also change the TB, or was it a TPS voltage adjustment that fixed the issue?

R