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Volvo 1991 740 Model
This system operates by returning some of the exhaust gases to the engine to be recombusted: since this
lowers the combustion temperature the amount of nitrogen oxides released into the atmosphere is
reduced.
The EGR valve should be inspected at 60,000 miles (96,000 km) and thereafter cleaned every 20,000
miles (32,000 km).
pg. 8:13 Servicing
WARNING!
The distributor ignition system operates at very high voltages. Special safety precautions must be
followed to prevent injury.
Always turn the ignition off when:
connecting engine test and diagnostic equipment to the vehicle (timing light, tach-dwell tester,
ignition oscilloscope, etc..).
Replacing distributor ignition components e.g. plugs, coil, distributor, HT leads etc.
Do not touch any part of the distributor ignition system while the engine is running. This may result
in unintended movements and body injury.
Replacing spark plugs
The spark plugs should be changed every 30,000 miles (48,000 km). However, city driving or fast
highway driving may necessitate changing after 15,000 miles (24,000 km) of driving. When installing
new plugs, be sure to fit the right type and use correct torque, see Specifications. When changing the
plugs, check that the suppressor connectors are in good condition. Cracked or damaged connectors
should be replaced.
When changing the spark plugs, clean the terminals and the rubber seals. If the car is driven on roads
where salt is used during the winter, coat the cables with silicone.
Battery:
Make sure the battery leads are properly connected and tightened.
Never disconnect the battery when the engine is running.
The battery leads must be disconnected when recharging the battery.
Turn radio off before disconnecting the battery. If the radio has an anti-theft code and the battery has
file:///K|/ownersdocs/1991/1991_740/91740_18.htm (10 of 11)12/30/2006 8:58:05 AM
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