Test 7 - Fuel-Cut System Operational Check
- Warm engine until choke is fully open, A/C off and connect tachometer. Connect voltmeter between ground and terminal A (Black/Green wire) of fuel-cut relay See Fig 1
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- Open throttle slightly and keep engine at 3500 RPM. Note voltage. If voltage is less than 6 volts, go to step 3). If voltage is greater than 6 volts, check for open between terminal A to ECM terminal No. 14. If wire is not open, adjust idle switch. If adjustment is okay, ECM or connection is faulty.
- Return throttle to idle and check voltage. If voltage changes, go to step 4). If voltage does not change, check adjustment of idle switch and A/C fast idle diaphragm.
- Voltage rises greater than 6 volts, then falls again to low level, when engine drops below 2000-2500 RPM. Fuel-cut circuit and idle switch adjustment are okay. If A/C equipped, repeat test with A/C on.
Courtesy of GENERAL MOTORS CORP.