Cold DRIVEABILITY Test 13 - Idle Rpm Check
- Turn all lights and accessories off. Place transmission in neutral. Set parking brake. Start and run the engine until normal operating temperature is reached. Ground the carburetor switch with a jumper lead. Disconnect and plug vacuum hose to the EGR valve.
- Disconnect and plug 3/16" vacuum hose from vapor canister. Remove PCV valve from the valve cover and allow it to draw outside air. On 2-Bbl. models, disconnect and plug vacuum hose from the computer. Disconnect the carburetor 4-way connector and remove the Green wire to the O2 solenoid from the connector.
- Reconnect the 4-way connector. Start and run the engine for 4 minutes before proceeding. On 4-Bbl. models, connect a voltmeter to the O2 solenoid (Green wire) and ground. Disconnect and ground wire from the O2 sensor using a jumper lead. Start engine and let idle until voltmeter reading is a steady 7-13 volts. This may take up to 4 minutes.
- Tachometer reading should be within specifications shown on emissions label. Set idle RPM to specifications as necessary. Tee in propane supply into the heated air temperature sensor vacuum hose. Open propane valve and meter in propane until maximum RPM is obtained. Engine speed should increase 60 RPM (2-Bbl. models) or 50 RPM (4-Bbl. models) plus or minus 50 RPM.
- Open throttle and position fast idle adjusting screw on the 2nd highest step of the fast idle cam. Fast idle speed should be set to specifications plus or minus 100 RPM. See FAST IDLE SPEED chart. Adjust fast idle speed to specifications as necessary.
FAST IDLE SPEED
| Carb. No. | Specification |
|---|---|
| 4324647 | 1700 |
| 4306433 | 1450 |