Toyota 4-Runner 1985 Repair Manual page 167

Sub-diaphragm
EMISSION CONTROL SYSTEMS (CARB.) - Auxiliary Systems EC-67
EC0381
EC0378 EC1193
EC0320
INSPECTION OF IDLE ADVANCE SYSTEM
CHECK IDLE ADVANCE SYSTEM OPERATION
(a) Warm up the engine to normal operating temperature.
(b) Check the ignition timing at idle.
Ignition timing: About 12° BTDC
@
Max. 950 rpm
A03085
(c) Disconnect the vacuum hose from the distributor sub-
diaphragm and plug the hose end.
(d) Check the ignition timing at idle.
Ignition timing: 0° BTDC
@
Max. 950 rpm
(e) Reconnect the vacuum hose and remove the timing
light.
IF NO PROBLEM IS FOUND WITH THIS INSPECTION, THE
SYSTEM IS OKAY; OTHERWISE INSPECT EACH PART
INSPECTION OF DISTRIBUTOR VACUUM
ADVANCER
CHECK OPERATION OF VACUUM ADVANCER BY
APPLYING VACUUM
(a) Remove the distributor cap and rotor.
(b) Check that the vacuum advancer moves is accordance
with the vacuum.
(c) Reinstall the rotor and distributor cap.
If a problem is found, repair or replace the distributor vacu-
um advancer.