A few important items to check first:
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.
- 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.