Basic Checks

A few important items to check first:

CIS.0111. Slack Tube Test

The slack tube tester will check for leaks in the evaporative emissions system – leaks which may cause fuel contamination.

The evaporative emissions system must also “hold” pressure to prevent “vapor lock.”

  • Mount the slack tube tester vertically. Remove smallest hose from charcoal canister and attach hose to slack tube tester.
  • Open both valves on slack tube % turn. Slide measuring scale to “zero”.
  • Using hand pump, pressurize the system to 1.3 inches of mercury.
  • Pressure should not drop below 1.2 inches of mercury within 5 minutes.

If test fails, see page 29.


CIS.0122. Two Notch Check Valve

  • Examine the check valve located at the fuel filter outlet (1978-1979 models).
  • Check valve should have two notches on hex corners.
  • Replace valve which has one notch with two notch valve from kit #035198999.  Use new seals.
  • Remove pressure relief valve from fuel distributor.
  • Clean opening in fuel distributor with a small magnet.
  • Install pressure relief valve using new parts from kit.


3. 1980 PCV Restrictor

  • Remove the PCV hose from the intake manifold (1980 models).
  • If a plastic restrictor is not in the manifold pipe – install part #049103271A.