Volvo 780 Owner's Manual page 96

1987 Volvo 780
The manifold nuts should be torqued at the 600-1,200 mile (1,000-2,000 km) inspection.
A loose manifold could alter air/fuel ratio and cause an increase in emissions and/or poor driveability.
Valves
The valve clearance should be checked and, if necessary, adjusted every 30,000 miles (50,000) km).
Air cleaner
Replace the air cleaner cartridge with a new one every 30,000 miles (50,000 km). The cartridge should be replaced more often when driving
under dirty and dusty conditions. The filter cannot be cleaned and therefore, should always be replaced with a new one.
Vacuum fittings, hoses and Connections
Unstable idle, misfiring, or poor emission control is often caused by leaking vacuum hoses or connections. Check hoses and connections on
distributor vacuum unit, connections on heater control servo systems and hydraulic brake servo.
Checking and adjusting idle speed
Your Volvo is equipped with an electronically controlled idle speed system that requires no checking or adjustment.
Fuel system cap, tank and lines, and connections
The effectiveness of the fuel system to contain hydrocarbons is dependent largely on a leak free system. Check for proper sealing of
gasoline filler cap which contains "O" ring-type seals. Check all evaporative hoses in vehicle for tightness. Check fuel lines under vehicle
and repair if necessary.
Fuel (line) filter
This filter is to be changed every 60,000 miles (100,000 km). The filter is replaced as one complete unit.
Replace more frequently if contaminated fuel is introduced into the tank (or if there is reason to suspect that this has occurred).
pg. 96 Servicing
1 Battery
2 Injection control unit
3 Ignition control unit
4 Fuel filter
5 Fuel pump
6 Fuel feed pump
7 Air mass meter
8 Throttle switch
9 Temperature sensor
10 Injector
11 Oxygen sensor
LH Jetronic 2.2 fuel system
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