Honda Acura NSX 1991, Service Manual

Page: 279 / 1420

Main Relay
Description
The main relay actually contains two individual relays.
This relay is installed behind the passengers seat back
panel.
One relay is energized whenever the ignition is on which
supplies the battery voltage to the ECU, power to the
and power for the second relay.
The second relay is energized for 2 seconds when the
ignition is switched on, and when the engine is running
which supplies power to the fuel pump.
MAIN RELAY
I
FUEL PUMP
L
R E S I S T O R
I N J E C T O R
Relay Testing
NOTE: If the car starts and continues to run, the main
relay is OK.
1 . Remove the main relay.
2. Attach the battery positive terminal to the No. 4
terminal and the battery negative terminal to the
No. terminal of the main relay. Then check for
continuity between the No. 5 terminal and No. 7
terminal of the main relay.
If there is continuity, go on to step 3.
l If there is no continuity, the relay and
retest.
No.
No. 1
No.
No. 2
TO 1
TO 1
TO ST. SWITCH
TO BAT
TO ECU
TO FUEL PUMP
3. the battery positive terminal to the No. 6
terminal and the battery negative terminal to the
No. 2 terminal of the main relay. Then check that
there is continuity between the No. 1 terminal and
No. 3 terminal of the main relay.
If there is continuity, go on to step 4.
l
If there is no continuity, replace the relay and
retest.
4. Attach the battery positive terminal to the No. 3
terminal and battery negative terminal to the No. 8
terminal of the main relay. Then check that there is
continuity of the main relay. Then check that there
is continuity between the No. 5 terminal and No. 7
terminal of the main relay.
If there is continuity, the relay is OK;
If the fuel pump still does not work, go to
Harness Testing in the next column.
If there is no continuity, replace the relay and
retest.