Diagnostic Tools
- The Closed Loop Emission Control system does not require special tools for diagnosis. A dwell meter, tachometer, test light, ohmmeter, digital voltmeter with 10 megohms impedance (minimum), vacuum pump, vacuum gauge and jumper wires are the only tools necessary for diagnosis.
- A test light, rather than a voltmeter, must be used where indicated in diagnostic chart. A dwell meter is used to measure the time that the vacuum control solenoid is on or off. This gives an indication of how the system is working and how rich or lean the mixture. The dwell meter is set for 4-cyl. scale.
- Dwell meter is connected to Green connector located near carburetor. This connector will not be connected to any circuit EXCEPT when testing with the dwell meter. Do not allow terminal wire to come in contact with any ground source, including rubber hoses.NOTE: If engine operation seems to change when dwell meter is connected to Green wire, remove dwell meter and use another type. A few brands are not compatible with the electronic emission system.
- When engine is at operating temperature and idling, dwell meter needle will move up and down the scale. This indicates the system is in closed loop operation. If the needle does not move, the system is in open loop operation.