RX7 2RTR-1308cc 80 (1984)
Alternator: Testing and Inspection
Battery Discharges
1.
With engine idling, measure voltage of alternator B terminal, then measure B terminal voltage at engine speed of approximately 2000 RPM.
Compare voltage at idle to voltage at 2000 RPM. If voltage does not change, proceed to step 2. If voltage at 2000 RPM is higher, proceed to step
6.
2.
Stop engine and place ignition switch to On position, then check voltage at alternator L terminal. If voltage is 0-1 volt, proceed to step 3. If voltage
is same as battery voltage, proceed to step 5. If voltage is 1-3 volts, proceed to step 6.
3.
Short circuit alternator B and R terminals using suitable jumper wires, then repeat step 2. If voltage is 0-1 volt, proceed to step 4. If voltage is 1-3
volts, correct poor ground at chassis side.
4.
On RX-7 models, disconnect alternator electrical connector, then check continuity between L and R terminals using a suitable meter. If meter
indicates 35-100 ohms, IC regulator is defective. If no continuity is present, IC regulator is defective.
5.
On all models, with engine stopped and ignition switch in On position, measure voltage at alternator F terminal. If voltage is same as battery
voltage, IC regulator is defective. If voltage is 0-.5 volts, check for poor brush contact or defective field coil. If voltage is .5-2 volts, (+) diode has
short circuit. When measuring voltage at F terminal, ensure voltmeter test leads do not touch.
6.
Disconnect alternator B terminal electrical connector, then connect ammeter between wiring and terminal. Start engine and suddenly increase
engine speed to 2500-3000 RPM, then immediately read maximum indication of meter. If meter reads 70% or less of idle output, alternator is
defective. If meter reads 70%-90% of idle output, proceed to step 7. If meter reads 90% or more of idle output, alternator is satisfactory. Test
should be performed with all electrical loads left on.
7.
Check for poor contact between alternator B terminal and battery positive terminal, then slightly discharge battery and repeat step 6. If meter reads
90% or less of idle output, remove alternator from vehicle and inspect carefully. If meter reads 90% or more of idle output, alternator is
satisfactory.
8.
Disconnect battery positive terminal and connect suitable ammeter between cable and battery. Before starting engine, short circuit ammeter
terminals so starter current will flow to ammeter.
9.
Start engine and read ammeter reading at engine speed of 2500 RPM. If meter reads less than 5 amps, measure L terminal voltage. If meter reads 5
amps or more, either charge battery until it becomes less than 5 amps or replace with new battery and measure again. If voltage is 14.7 volts on
RX-7 or 14.2 volts on B2000, IC regulator is satisfactory. If voltage is not 14.7 volts on RX-7 or 14.2 volts on B2000, alternator is defective.
