After warm-up, this system forcibly releases the fast idle cam, which lowers the engine speed.
- Use a 3-way connector to attach a vacuum gauge to the fast idle cam breaker.
- Use enough vacuum line to bring the gauge into the vehicle and set it on the drivers seat.
- Perform a road test observing the speedometer and vacuum gauge.
With the coolant temperature below (122°F) check that the gauge reads zero regardless of engine speed.
- Warm the engine and check that the vacuum gauge indicates high vacuum below 7 mph.
- Check that the vacuum gauge indicates lower vacuum than the vacuum indicated in Step 4 at 16 mph.
- Disconnect the vacuum gauge and reattach the hose to its proper location.
- Stop the engine.
- Disconnect the hose from the fast idle cam breaker.
- Set the fast idle cam.
- While holding the throttle valve slightly open, pull up the fast idle cam and then release the throttle.
- Start the engine, but do not touch the accelerator.
- Reconnect the hose and check that the fast idle cam is released and the engine rpm is lowered.
If the above tests are positive, this procedure is complete. If not, inspect the breaker diaphragm, TVSV valve, speed sensor or VSV.