Service Manual

Checking, control unit
Com puterized ign ition system s
66
Mt2
Check vacuum advance
Run engine at 25 /s (1500 r/min).
Disconnectvacuum hose. Becord ignition advance. Re_
connect hose and check that advance allers.
lf not, check for vacuurn at control unil {check suction at
lf vacuum, but no advance, replace control unit
Check dwell angle
Read off dwell angle at idle.
M13
Dwell angle = 36 38'.
Increase engine rpm and check that dwell angLe increases.
if no increase is recorded, replace control I'nit,
B23F
Checking knock sensor
M14
connect a volvo Monotesrer or equivalenl test nreter.
Srart engine (AC disconnected).
Increase engine speed and mainlain al sel leve by e.g.
pLacing screwdriver across throttle pulley.
M15
Tap plug on rishtside on cylinder blockwith a hammer'
lgnition should retard by max6'and return aulomatrcal
t';