This article will explain how to inspect and replace the spark plugs on your Pro XD 2000G and 4000G vehicles. To order new spark plugs for your vehicle, contact your authorized Commercial Dealer.
Spark Plug Gap/Torque
See the chart below for spark plug specifications.
|Model Year||Electrode Gap||New or Used Plug Torque|
|2021||0.03 in (0.85 mm)||15 ft-lbs (20 Nm)|
|2020||0.03 in (0.85 mm)||7-8 ft-lbs (11-13 Nm)|
Spark Plug Inspection
Spark plug condition is indicative of engine operation. The spark plug firing end condition should be read after the engine is warmed up and the vehicle is driven at higher speeds. Immediately check the spark plug for correct color.
Caution: A hot exhaust system and engine can cause burns. Wear protective gloves when removing a spark plug for inspection.
To inspect the spark plugs, do the following:
1. Lift the rear cargo box to access the spark plugs.
2. Remove the spark plug cap. Using the spark plug wrench provided in the tool kit, remove the plug by rotating it counterclockwise.
3. Reverse the procedure for spark plug installation.
4. Torque to 15 ft-lbs (20 Nm).
The normal insulator tip is gray, tan or light brown. There will be few combustion deposits. The electrodes are not burned or eroded. This indicates the proper type and heat range for the engine and the service.
The tip should not be white. A white insulator tip indicates overheating, caused by use of an improper spark plug or incorrect throttle body adjustments.
Wet Fouled Plug
The wet fouled insulator tip is black. A damp oil film covers the firing end. There may be a carbon layer over the entire nose. Generally, the electrodes are not worn. General causes of fouling are excessive oil, use of non-recommended oil or poor fuel quality.