High Altitude

1986 Toyota Pickup Base, 22-RTE, R151FSECTION High Altitude
  1. Warm up engine and check ignition timing at idle. Disconnect hose from distributor sub-diaphragm, and plug hose end.
  2. Check ignition timing. Timing should be 0° BTDC. Reconnect hose to sub-diaphragm. Verify that timing advances to about 12° BTDC.
    Fig 1: HAC System
    G38379Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  3. Disconnect vacuum hose between check valve and vacuum pipe at vacuum pipe side. Plug pipe end. Ignition timing should remain stationary for more than one minute. Stop engine and reconnect hoses to proper locations.
  4. Remove 3 hoses from ports on top of HAC valve. Blow air into each hose and check that air flows into carburetor. Reconnect hoses to proper locations.
RENDER: 1.0x

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • You smell fuel, burning insulation, or see smoke.
  • Brakes feel soft, pull hard to one side, or make grinding noises.
  • The engine overheats, stalls repeatedly, or misfires under load.
  • You are missing required tools, torque specs, or safe lifting equipment.
  • You are not confident in the next step or safety outcome.