Eldorado V8-300 4.9L (1991)
Idle Speed: Adjustments
Idle Speed
1.
Start the engine and enter diagnostics. Select PCM/ECM Override ES03, ISC Motor.
2.
Press the cooler button to retract the ISC motor. The ISC motor will slowly retract (about 20 seconds). This action will disengage the A/C
compressor, command EGR "OFF" and turn off the generator. The Climate Control Center display will change from "50" to "00". Verify that the
throttle lever is resting on the minimum idle speed screw. If the engine stalls at this point, go to step 6.
3.
With the ISC fully retracted, the plunger should not be touching the throttle lever. If contact is noted, adjust the ISC plunger (turn in) with pliers or
available special tool J-29607 so that it is not touching the throttle lever. Make sure that the throttle is not being bound by the cruise, TV, or
throttle cables. The throttle lever must be resting on the minimum air screw.
4.
Press the cooler button to retract the ISC motor. The ISC motor will slowly retract (about 20 seconds).
5.
Check the minimum idle speed using PCM/ECM data parameter ED11, Engine RPM. If the minimum idle speed is outside its limits adjust the
minimum idle screw, refer to MECHANICAL SPECIFICATIONS.
If engine speed is not within the above limits, check for vacuum leaks at the throttle body, intake manifold, vacuum fittings, tees and hoses. If the
minimum air setting is made with a vacuum leak present, fuel control can be adversely affected throughout the driving range.
6.
If the engine stalled at minimum air (ISC fully retracted), check the throttle blades for deposits that might restrict air flow. If there are deposits,
clean the primary throttle bore and the area behind and around the throttle plate. Return to step one after cleaning the throttle body.
ISC SOLENOID
1.
With key on select the ISC motor override ES03. Press the warmer button on the CCDIC. The display should change from 50 to 99 indicating that
the override function has started. The ISC will extend to the maximum extended position.
2.
With the ISC fully extended, the TPS parameter ED01, should be between 13.4 and 15.8. If the parameter is not within this range, adjust the ISC
Plunger as follows:
^
TPS below 13.4°.
-
Adjust the ISC plunger out by turning the plunger counterclockwise until the TPS parameter reads 15.0°.
^
TPS above 15.8°.
-
Adjust the ISC plunger in be turning the plunger clockwise until the TPS parameter reads 15.0°.
*** UPDATED BY TSB #91-I-11 DATE: 10/90
IDLE LEARN PROCEDURE
Idle learn is used during coast down to compensate for loss of air flow due to throttle body deposits. If the battery is disconnected for a service procedure
or any other reason, the learned value for the idle throttle angel offset is lost. The reset procedure allows the idle learn routine to seek and retain the
proper throttle angel for each particular throttle body condition. This decreases the potential for stalling during coast down.
Before performing the reset procedure all service procedures must be complete., and the engine must be running continuously for a minimum of 18
minutes on 1990 vehicles, and 13 minutes on 1991 vehicles.
Reset procedure:
1.
Place the vehicle transmission in drive wither the brakes applied.
2.
Place vehicle climate control in the OFF position and allow the engine to remain at IDLE for at least one minute.
3.
Make sure the outside air temperature reading is at least 50°F. Place the vehicle climate control in the AUTO position, verify A/C clutch
engagement, and allow the engine to remain at IDLE for at least one minute.
4.
Place the3 transmission in Park and turn off the ignition.
IMPORTANT: Because of the load differences on the engine with A/C on versus A/C off, it is very important than learning be allowed under both
conditions.
