1995 P30 ECM Faults (454 TBI)
My MH has been constantly idling way too high whether it is hot, cold, etc. I checked the ECM codes and below is what I found: 32 - egr circuit (fuel-injected models); DTC - 32 EGR system failure 3...
Forum Discussion
When diagnosing OBD-1 TBI engine always start with the smallest ECM code first in your case 32. Your min idle should be 800rpm (in Park/Neutral) with everything running correctly. The 625 +- is in Drive selection. That is also factory set by GM and the min idle speed screw is covered on the TBI.
From 1995 Chevy manual....
Looking at the 1994 service manual for 454 TBI under fuel systems (Section 4-4A) the 'Min idle speed' setting is... (Factory set screw) not recommended to adjust.
Min idle speed:
For the 7,4L auto trans in Drive (wheels chocked) is 625 (+-25rpm) Closed loop
Controlled Idle Speed is as follows:
Put 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
