A) Adjusting dwell angle
Connect BMW Programm Tester.
Check contact breaker points for perfect condition and
replace if necessary.
With engine ticking over at starter motor speed adjust
dwell angle to 35° ÷ 41°. Try to obtain smallest angles
possible.

B) Adjusting ignition timing
Pull off vacuum hoses for ignition advance (1) and retard (2).

Increase engine speed to 1700 rpm by turning adjusting
screw in the bearing block on the throttle linkage.
Note: After having adjusted ignition timing, turn out
adjusting screw until there is clearance between the screw
and the revolving shaft.

Switch off advance angle indicator with set wheel.
Point strobe timing light at ball marking¹) on flywheel.
Turn distributor until the indicator in the clutch casing points
at the middle of the ball.
Re-connect vacuum hoses.
At 900 ÷ 1000 rpm the tdc mark must be visible through
the sight hole.
Ignition retard²) is operating correctly if the engine speed
increases substantially after vacuum hose (2) has been
pulled off.

¹) For Automatic transmission: long taper peg indicates
ignition timing.
²) CF. (E) ignition switch-over.

C) Adjusting idle speed and CO-volume
Remove air filter 13 71 000.
Note when re-fitting: Connect hoses.


13 71 000

Disconnect linkage bar (1).
Synchronize both carburettors at idle speed¹).
This is done by turning screw 2 and 3 and then 4 and 5
until the raading on the synchronizing unit²) is 0 (zero).
¹) 900 ÷ 1000 rpm.
²) Sold by Cartool Company Hans Schubert Ingolstadt,
West Germany.

Remove the two plug screws on the exhaust manifold and
insert analyser probe.
By turning screws 2 and 3 on the carburettor adjust the CO-volume
for each exhaust manifold to 1.5 Vol.%.

Fit on air filter.
Attach analyser probe to end of exhaust pipe.
By turning screws 2 and 3 on the carburettor adjust the
CO-volume to a final value of max. 2.0 Vol.%.

D) Adjusting compensation speed - dashpot
Pull off vacuum hose (6).
Increase engine speed to approx. 2500 rpm and then slowly
decrease.
At 1800 ± 100 rpm, dashpot plunger (7) must touch carburettor
linkage (8).
Correct if necessary by turning dashpot (9) after having
loosened nut (10).
Re-connect vacuum hose (6).

Engine speed lower than 1800 ± 100 rpm but dashpot plunger
(7) does not free carburettor linkage:
Pull off vacuum hose (6).
Check with finger-tip whether there is suction.
If there is a vacuum, the dashpot (9) must be replaced.

If there is no suction in vacuum hose (6), check plug connections
in engine sped relay (11) or provide perfect ground contact.

If dashpot plunger (7) still does not free the carburettor linkage,
pull cable (12) off magnetic valve (13) and connect to voltmeter.
Increase engine speed to 2000 rpm.
If the voltmeter reading is 12 V, magnetic valve (13) is defective.
If there is no reading on the voltmeter, speed sensitive relay
(14) must be replaced.

E) Ignition timing switch-over
Up to 2500 ± 100 rpm, the ignition is set to retard and
above 2500 ± 100 rpm to advance.
Retard does not operate:
Pull off vacuum hose (1).
Check with finger-tip whether there is suction.

If suction can be felt in the vacuum hose, pull plug off
magnetic valve (17) and connect to voltmeter.
Increase engine speed to 2200 ± 100 rpm.
If the voltmeter reading is 0 (zero) volts, speed sensitive
relay (16) is defective.
If there is no suction in the vacuum hose, but the voltmeter
reading is 12 volts up to 2200 ± 100 prm, magnetic valve
(17) is defective.

F) Exhaust gas recirculation system
Every 24,000 km (16,000 miles) remove the exhaust gas
recirculation pipes from the exhaust manifold to the intake manifolds
and clean on the inside by using a suitable tool.
Note: Be careful not to roughen the inside of the pipes
in this process.
Take olut battery. Drain some of the coolant.
Note when re-fitting: Bleed coolant system 17 00 039.
Disconnect linkage rod (1).
Loosen fastening on oil dipstick insert tube.
Disconnect exhaust gas recirculation pipes (2) at the intake
manifolds and diaphragm valve and lift out.


17 00 039

Disconnect coolant hoses (3) and (4) at the splashboard.
Remove hose (5) at the equalizing reservoir and hose (6) completely.

Remove flow tube for hot air at rear.
Disconnect exhaust gas recirculation pipe (7) from exhaust
manifold.

Disconnect strap holding recirculation pipe.

Remove exhaust gas recirculation pipes (7) and (8).
Note when re-fitting: Apply graphite grease to the screwed
connections and check for tightness with the help of water.
When spraying water onto a leaking screwed connection, the
engine speed will drop.

Check diaphragm valve - exhaust gas recirculation system
connected.
Set engine speed 900 + 50 rpm.
Pull control hose leading to diaphragm valve off carburettor
and connect to vacuum hose for secondary crankcase vacuum
control.
The diaphragm valve is functioning correctly if engine speed
then drops to approx. 700 ÷ 750 rpm.

If engine speed hardly, changes, the exhaust gas recirculation
pipes are obstructed (cross-section too small) or the diaphragm valve is
defective.
Detach recirculation pipe form diaphragm valve on the right hand side
and plug the open end. Disconnect cyclone filter.
No exhaust fumes may escape when engine is idling.
If the diaphragm valve is not tight, it will cause engine to run
unsmoothly when idling and must be replaced.

Pull vacuum hose off diaphragm valve.
With engine running above 2000 rpm, a vacuum must be felt
when closing the vacuum hose.
If there is a vacuum but no exhaust fumes escape under
pressure above 2000 rpm, the plunger in the diaphragm valve
is stuck. To remedy, replace diaphragm valve.

Always replace cyclone filter and diaphragm valve every
84,000 km (56,000 miles).

G) Evaporative control system
The maintenance-free activated carbon filter is mounted
beneath the battery support.

Layout of fuel evaporative control system
1 air filter
2 activated carbon filter
3 fuel equalizing reservoir
4 fuel filler cap (not vented)
5 pipe to rear carburettor
6 fuel pump

Layout of fuel evaporative control system
1 air filter
2 activated carbon filter
3 fuel equalizing reservoir
4 fuel filler cap (not vented)
5 pipe to rear carburettor
6 fuel pump

Layout of crankcase vacuum control

Layout of exhaust emission control system
(1) vacuum hose (retard)
(2) vacuum hose (advance)
(3) vacuum socket
(4) distributor
(5a) engine speed relay for valve (6)
(5b) engine speed relay for valve (7)
(6) two-way magnetic valve (advance)
(7) two-way magnetic valve (retard)
(8) vacuum pipes
(9) dashpot
(10) exhaust gas recirculation pipe
(11) diaphragm valve
(12) vacuum hose from (13) to (11)
(13) carburettor
(14) cyclon filter