udidwht
RVF Regular
- Joined
- Dec 4, 2022
- Messages
- 12
See those asking about this often. This is factory set and not recommended adjusting. But the following are the specs regarding 'Min idle speed setting'.
Looking at the 1994 service manual for 454 TBI under fuel systems (Section 4-4A) the 'Min idle speed' setting is... (Factory set screw)
Min idle speed setting:
For the 7,4L auto trans in Drive (wheels chocked) is 625 (+-25rpm) Closed loop (IAC must be closed and disconnected at normal operating temp).
Controlled Idle Speed is as follows:
454 7.4L in Drive (wheels chocked) 675 (+- 25rpm) IAC count 5-30 (Closed loop) at operating temp 196-222F (add 2 counts for every 1000ft above sea level
The 'controlled idle speed' is obtained by the control module positioning the IAC valve. A high/low coolant temp or AC clutch engagement may signal the control module to change the IAC counts.
IAC counts will be above 60 if idle is too low and zero counts if idle is too high. Things to check if so...
1. Vacuum leak/s
2. System too rich
3. TB obstruction
4. PCV issue
5. AC issue
Looking at the 1994 service manual for 454 TBI under fuel systems (Section 4-4A) the 'Min idle speed' setting is... (Factory set screw)
Min idle speed setting:
For the 7,4L auto trans in Drive (wheels chocked) is 625 (+-25rpm) Closed loop (IAC must be closed and disconnected at normal operating temp).
Controlled Idle Speed is as follows:
454 7.4L in Drive (wheels chocked) 675 (+- 25rpm) IAC count 5-30 (Closed loop) at operating temp 196-222F (add 2 counts for every 1000ft above sea level
The 'controlled idle speed' is obtained by the control module positioning the IAC valve. A high/low coolant temp or AC clutch engagement may signal the control module to change the IAC counts.
IAC counts will be above 60 if idle is too low and zero counts if idle is too high. Things to check if so...
1. Vacuum leak/s
2. System too rich
3. TB obstruction
4. PCV issue
5. AC issue
