Basic Idle Speed

NOTE: ALWAYS check TPS adjustment after adjusting basic idle speed. See THROTTLE POSITION SENSOR (TPS) .

NOTE: For Data Link Connector (DLC) location, see TESTS W/CODES article in this section.

NOTE: Ensure vehicle is at normal operating temperature with all lights, cooling fan and accessories off. Shift transmission into Neutral or Park position.

Insert paper clip or appropriate probe into tachometer connector. See TACHOMETER CONNECTOR LOCATION table. Connect a primary voltage detecting type tachometer to paper clip.
Connect a jumper wire between data link terminal No. 10 and vehicle ground. See Fig 1 . Connect a jumper wire between ignition timing adjustment connector and vehicle ground. See IGNITION TIMING ADJUSTMENT CONNECTOR LOCATION table under IGNITION TIMING.
Start and run engine at idle. Check basic idle speed. See IDLE SPEED SPECIFICATIONS table. If idle speed is not within specifications, turn engine speed adjusting screw until correct engine speed is obtained. See Fig 2 . Access to speed adjusting screw is obtained by removing rubber plug on throttle body.
If idle speed cannot be lowered by adjusting engine speed adjusting screw, determine if fixed speed adjusting screw (stop screw contacting throttle lever) has been adjusted. See FIXED SPEED ADJUSTING SCREW for procedure.

After all adjustments are verified correct, possible cause of incorrect idle speed is deterioration of fast idle air control motor. Throttle valve must be replaced to correct symptom. Disconnect jumper wires and recheck idle speed.

TACHOMETER CONNECTOR LOCATION

Application

Type

Location

All Models

1-Pin

⁽¹⁾

⁽¹⁾	Next to ignition timing adjustment connector.

IDLE SPEED SPECIFICATIONS

Application	Curb Idle	Basic Idle
1.5L	650-850	650-850

Fig 1: Locating Data Link Connector (Typical)

Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

Fig 2: Adjusting Idle Speed (Typical)

Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.