Advance Piston Diagnosis

Advance Piston Group:

If the injector pump is determined to be the cause of "low power and excessive smoke" when the engine is cold, the advance piston should be checked for binding or sticking. The following procedure will diagnose a binding or sticking advance piston.

Remove or Disconnect:
1. Remove injection pump. Mount pump in a holding fixture in the inverted position
2. Rocker lever
3. Cam advance pin plug
4. Cam advance pin
5. Advance piston bore plugs

Caution: Do not exceed the pistons normal travel or rotate the piston in the bore. This could damage the piston or bore.

Inspect:
- Push piston back and forth in the bore using light finger pressure
- If the piston drags or sticks, this should be noted when the pump is sent in for repair


Install or Connect:
1. Cam advance pin
2. Cam advance pin plug, with a new seal
3. Advance piston bore plugs, using new seals
4. Rocker lever
5. Injection pump