Monitor Actuation Test

CAUTION: The main purpose of this test is to identify potential engine mechanical condition problems and fuel and ignition systems problems that are not common to all cylinders. For best results, perform this test while maintaining as steady an rpm reading as possible.

CAUTION: Before beginning tests; set the parking brake, place gear selector in P or N and block drive wheels for safety.

Warm up the engine to normal operating temperature and let it idle.
Install Scan Tool and select "ENGINE RPM" parameter on the Current Data mode.
Monitor engine rpm and shut off the injector #1 by disconnecting connector at the injector.
Repeat procedure on all injectors and record the engine rpm.
1. Specification : All cylinders should show an even RPM drop.
  
  Fig 1: Monitoring Engine RPM
Was each cylinder's rpm drop within the same value?
YES
1. Go to "CHECK INTAKE/EXHAUST SYSTEM FOR RESTRICTION OR LEAKAGE " procedure.
NO
1. Cylinders with the least amount of RPM drop are not contributing their share of power.
2. Go to "FUEL INJECTOR INSPECTION " procedure and check the suspect cylinders.
  CAUTION: If the RPM loss between cylinders is quite large (200 RPM or more) and engine has high mileage, there is possibility of engine wear. Perform compression test with pressure gauge to check the engine wear.