Wrangler L4-150 2.5L VIN H TBI (1986)
Idle Speed: Adjustments
Idle Speed Adjustment
Curb Idle Speed Adjustment
Fig. 2 Curb idle adjusting screw. 1984-86 4-150/2.46L engine w/ Carter YFA 1 barrel carburetor
1984-86 4-150/2.46L ENGINES W/ CARTER YFA CARBURETOR
1.
With engine at operating temperature, connect a suitable tachometer to engine.
2.
To adjust idle speed, turn hex head adjusting screw located at rear of solenoid, Fig. 2.
3.
After adjusting curb idle speed, apply 10 to 15 inches Hg. of vacuum to Sole-Vac actuator with a hand held vacuum pump.
4.
If necessary adjust Sol-Vac idle RPM by turning vacuum actuator adjusting screw.
Fig. 3 Diagnostic connector. 1984-87 4-150/2.46L engines
1986-87 4-150/2.46L ENGINES W/ THROTTLE BODY INJECTION (TBI)
Idle speed is controlled by the Electronic Control Unit (ECU), which positions an Idle Speed Actuator (ISA) motor plunger to provide the proper
throttle angle. The ISA motor plunger is only adjusted after the motor has been removed or replaced.
1.
Remove air cleaner, then start engine and allow to reach operating temperature.
2.
Connect a suitable tachometer to diagnostic connector D1 terminals 1 and 3, Fig. 3.
3.
Ensure A/C control switch is in the off position, if equipped.
4.
Place ignition switch in the off position while observing ISA plunger. Plunger should move to the fully extended position.
5.
With plunger in the fully extended position, disconnect ISA motor electrical connector and start engine.
6.
Adjust engine idle speed to 3500 RPM by rotating hex head screw on end of plunger.
7.
Press end of ISA motor plunger inward until it is fully retracted. Ensure a clearance exists between end of plunger and throttle and lever. If not
clearance does not exist, check throttle linkage and correct as necessary.
8.
Connect electrical connector to ISA motor, then place ignition switch in the off position for at least 10 seconds. The ISA motor plunger should
move to the fully extended position.
9.
Start engine and note RPM readings on tachometer. Engine should operate briefly at 3500 RPM, return to normal idle speed.
10.
After the proper setting has been obtained, apply a suitable thread locking compound to the ISA motor plunger adjusting screw.
Fast Idle Adjustment
