Run the engine until it reaches normal operating temperature, and connect
a tachometer to the engine.
Connect a voltmeter to the brown and yellow wire in the electrical connector
of the EGR solenoid valve.
Start the engine and quickly rev it to 2,500 rpm. Current should flow to
the terminal for a few seconds and then stop.
Fig. 1: Detach the connector from the No. 1 water
temperature switch, and connect a jumper wire — 1980
RX-7
Disconnect the electrical coupler of the vacuum switch and connect a jumper
wire to both terminals in the coupler. Increase engine speed with the throttle.
Current flow to the solenoid valve should stop when the engine speed is 2,700–3,300
rpm for manual transmission models, or 3,000–3,600 rpm for automatic
transmission models.
Increase the engine speed to 2,000 rpm with the throttle. Slowly decrease
the engine speed and record the engine speed at which the current stops flowing
to the terminal. Engine speed should be around 1,050–1,250 rpm.
Slowly increase the engine speed from idle and check the engine speed at
which the current begins to flow. Compare this figure with that recorded in
Step 5. The difference in engine speed between the two should be about 90–220
rpm.
On vehicles equipped with a manual transmission, increase the engine speed
to 2,000 rpm with the throttle. Current flow to the terminal should stop when
the idle switch lever is fully pushed up to the idle position.
Disconnect the coupler of the No.1 water temperature switch, then connect
a jumper wire to both terminals on the wiring harness, as illustrated. No
current should flow to the solenoid valve at any rpm.
Stop the engine, then start the engine with the choke knob pulled fully
out, and set the engine speed at 2,000 rpm with the choke knob. Current should
flow to the solenoid after 104–156 seconds from the time the engine
was started with the choke valve pulled out.
On vehicles with a manual transmission, set the engine speed to 2,000 rpm
using the throttle, then depress the clutch pedal and shift the transmission
into 4th and 5th gears. Current to the solenoid should stop when the gears
are engaged.
If the results of all tests are as described above, the EGR signal system
is working properly.
