Checking And Adjusting Idle Air Control System; Timing Belt; Fuel System Cap, Tank And Lines And Connections; Charge Air Cooler (Intercooler) - Volvo 850 Owner's Manual

1996 Volvo 850
Unstable idle, misfiring, or poor emission control is often caused by leaking vacuum hoses or
connections. Check all vacuum hoses and connections.

Checking and adjusting idle air control system

Your Volvo is equipped with an electronically controlled idle air control system that requires no
checking or adjustment.

Timing belt

For proper functioning of the vehicle and its emission control systems, Volvo recommends that the
timing belt be replaced every 70,000 miles (112,000 km).

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 the gasoline filler cap which contains "O" ring type seals.
Fuel (line) filter
The fuel line filter is located next to the fuel pump. For proper functioning of the vehicle and its
emission control systems, the fuel line filter should be replaced at 100,000 miles (160,000 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).

Charge air cooler (Intercooler)

The B 5234 Turbo engine employs a turbo-compressor to force air into the engine inlet manifold and a
charge air cooler to cool the compressed inlet air. The resulting increase in air flow raises pressure in the
intake manifold by approx. 8.7 psi (over atmospheric pressure) and engine power output by approx. 50
horsepower over that developed by the normally-aspirated engine. The charge air cooler (which
resembles a radiator) is located between the turbo-compressor and inlet manifold.
file:///K|/ownersdocs/1996/1996_850/96850_806.htm (3 of 11)12/30/2006 9:59:52 AM