Heavy-duty trucks such as the Dodge Ram use a 5.9-liter Cummins 12-valve diesel engine. This engine relies on fuel injection to burn gasoline. If the spark from the vehicle's spark plug is not timed out correctly, the engine will fail to produce the desired acceleration. When this occurs, you need to set the injection timing of the vehicle.
Turn off the engine and open the hood. On the underside of the hood is a list of specifications regarding the vehicle. including the correct timing. If you do not have this printed list, consult your vehicle's owner's manual for the correct settings.
Remove the clamp around the vacuum hose connected to the distributor. Remove the hose.
Disconnect the #1 plug wire connected to the distributor and connect the lead wire from your timing light. The timing light helps you identify if the timing is correct. Attach the opposite wire on the timing light to the vehicle's battery.
Idle the engine and wait for it to heat up. The warmth of the engine expands many of the metals in the vehicle, allowing you to manipulate the placement easier.
Turn off the engine and loosen the clamp around the distributor but do not completely remove it. Start the engine back up, and aim the timing light toward the flywheel on the side of the engine. You can see a list of timing marks here. Take white chalk and draw a line on the timing mark you read on the hood specifications or owner's manual. With the mark in place, twist the distributor until the mark on the flywheel matches up with the timing light pointer.
Turn off the engine one final time and tighten the clamp around the distributor. Reattach the vacuum hose leading to the distributor. Remove the timing light and connect the #1 wire back to the distributor.
