Volvo-850-Fuel.pdf
Part A:
Chapter 4 Fuel system
Contents
| Accelerator cable removal, refitting and adjustment | Fuel injection systems general information 8 | |
|---|---|---|
| Air cleaner assembly and alr ducts removal and refitting See Chapter | 2 | Fuel injection system components removal and refitting 10 |
| Air cleaner element renewal | Fuel pump removal and refitting | 6 |
| Cruise control general information | 11 Fuel tank removal and refitting | 7 |
| Exhaust system check See Chapter | General information and precautions | 1 |
| Fuel filter renewal See Chapter | Inlet manifold removal and refitting | 12 |
| Fuel gauge sender unit removal and refitting | 5 Intake air pre-heating system | testing 3 |
| Fuel injection system testing | 9 Underbody and fuellbrake line check | See Chapter 1 |
Table Caption: This table outlines various maintenance and repair procedures for a vehicle's fuel system and related components, categorizing them by chapter.
Degrees of difficulty
Easy; suitable for novice with little experience for beginner with
Fairty easy; suitable some experience
Specifications
| B5204 S, and B5234 $ B5202 S, and B5252 $ engines B5204 T, and 85234 T engines B5254 S engines | LH3.2-Jetronic fuel injection system Fenix 5.2 engine management system Motronic 4.3 engine management system LH3.2-Jetronic fuel injection system; or Motronic 4.3 engine management system (according to market territory) |
|---|---|
| Fuel system data | |
| Idle speed*: Pre-1994 models 1994 models onward Idle mixture CO content* Fuel pump delivery rate Regulated fuel pressure 'Non-adjustable controlled by ECU | 800 rpm 850 rpm 1.45 to 2.41 litres/minute (at 12 volts) 3.03 bars |
| Recommended fuel | |
| Octane rating: Recommended | |
| Minimum | 91 RON unleaded |
| '98 RON unleaded fuel is recommended for B 5234 T5 engines | |
| Torque wrench settings Inlet manifold bolts | Nm 20 |
| Fuel rail to inlet manifold: | 10 Tighten through a further 75" |
| Stage 1 | |
| Fuel pump plastic retaining nut | 30 |
| Fuel gauge sender unit plastic retaining nut | |
| 40 | |
| Stage 2 |
Table Caption: This table provides specifications for various Volvo engines, detailing their engine management systems, fuel system data such as idle speed and pressure, recommended fuel octane ratings, and torque wrench settings for components like the inlet manifold and fuel rail. It also specifies torque settings for the fuel pump and fuel gauge sender unit retaining nuts, divided into Stage 1 and Stage 2.
System type
Fairly difficult
DlY mechanic suitable for competent
Difficult suitable for experienced DlY mechanic
Very difficutt;
suitable for expert DIY
or professional
2.1 Disconnect the air duct (A), ventilation hose (B), and wiring connector (C) at the air cleaner cover
General information
The fuel system consists of a centrallymounted fuel tank, an electric fuel pump, a fuel filter and a fully electronic fuel injection system. Further details of the fuel injection will be found in Section 8
Depending on engine type, models for some market territories are also equipped with an exhaust gas recirculation (EGR) system and secondary air injection system; as part of an emissions control package. Further details of these systems will be found in Part B of this Chapter .
valve, non turbo engines are equipped with a variable venturi inlet system whereby the inlet manifold incorporates two separate inlet tracts, each of different length and diameter, for each cylinder. The shorter tracts can be opened or closed by means of vacuum operated valves under the control of the ignition system ECU. At low engine speeds, both inlet tracts are opened to allow a rapid increase in airflow when the throttle is opened. At the mid-range speed, the valves are closed and airflow is through the longer tracts only. These are tuned for thís speed range to cause the inlet alr to resonate with the movement of the engine pistons and valves_ These 'pulses' coincide with inlet valve opening, providing a greater inlet charge than that of a conventional system. At high engine speeds both tracts are once again opened to provide maximum torque in this range. flap flap
Precautions
Warning: Petrol is extremely flammable great care must be taken when working on any part of the fuel system: Do not smoke
27a Disengage the air cleaner housing lower retainer (arrowed)
OF allow any naked flames or uncovered light bulbs near the work area. Note that gas powered domestic appliances with pilot flames, such as heaters, boilers and tumble dryers; also present a fire hazard bear this in mind if are working in an area where such appliances are present:. Always keep a suitable fire extinguisher close to the work area and familiarise yourself with its operation before starting work. Wear eye protection when working on fuel systems and wash off any fuel spilt on bare skin immediately with soap and water. Note that fuel vapour is just as dangerous as liquid fuel; a vessel that has just been emptied of liquid fuel will still contain vapour and can be potentially explosive; Petrol is a highly dangerous and volatile liquid, and the precautions necessary when handling it cannot be overstressed. you
Many of the operations described in this Chapter involve the disconnection of fuel lines, which may cause an amount of fuel spillage. Before commencing work, refer to the above Warning and the information in
When working with fuel system components, pay particular attention to cleanliness dirt entering the fuel system may cause blockages which will lead to poor running.
2.7b lift the housing up at the engine side
Removal
Air cleaner assembly
- detach the air 1 Slacken the hose clip and outlet duct and where applicable, the crankcase ventilation hose at the air cleaner cover (see illustration).
- 3 Release the HT lead to the ignition coil from the clips at the rear of the cover.
- 2 Disconnect the wiring connector from the mass air flow sensor or inlet air temperature sensor in the cover outlet.
- 4 Spring back the retaining clips; lift off the cover and remove the air cleaner element.
- 6 Detach the warm air inlet duct or turbocharger inlet duct, as applicable; from the air cleaner housing.
