Audi A8 1994 Service Manual page 50

Audi A8 1994 ➤
Motronic injection and ignition system (6-cylinder) - Edition 02.1999
Display Group 2: Intake air mass at idling speed with engine at normal operating temperature
Display xxx rpm
Indicates Engine speed
(in steps of 40 rpm)
Range min.: 550 rpm
max.: 6800 rpm
Specification 650...750 rpm
Note ---
If the specification is obtained:
- Press ⇒key.
- Press keys 0 and 6 for the function "End output" and confirm entry with the Q key.
- Switch off the ignition.
Reading Display Group 2
Display zone 3
Less than 1.0 ms - Lower values can only occur when vehicle is
on overrun
More than 4.0 ms - Load on engine due to ancillaries Protected by copyright. Copying for private or commercial purposes, in part or in whole, is not
permitted unless authorised by AUDI AG. AUDI AG does not guarantee or accept any liability
with respect to the correctness of information in this document. Copyright by AUDI AG.
- Rough idling (engine not running on all cyl‐
inders)
- Throttle valve control part -J338 defective
Reading Display Group 2
Display zone 4
Less than 3.0 g/s - Large quantity of unmetered air between in‐
take manifold and air mass meter
- Voltage supply to air mass meter or wiring
to
- engine control unit
More than 5.0 g/s - Load on engine due to ancillaries
- Voltage supply to air mass meter or wiring
to
- engine control unit
Testing power supply to air mass meter
46
24 - Mixture preparation, Injection
1 2
xx.x %
Load
min.: 0 %
max.: 100 %
12.0....26.0 %
---
Possible cause of fault
Possible cause of fault
Display zones
3
x.x ms
Meaninjection period
min.: 1.0 ms
max.: 20.0 ms
1.0....4.0 ms
If readout does not match
specification, see table for
display zone 3 => Page
46
- Eliminate load (air conditioner, power steer‐
ing, alternator)
- Test spark plugs
Test injectors => Page
- Test throttle valve control part
=> Page
- Check intake system for leaks
(unmetered air) => Page
- Eliminate load (air conditioner, power steer‐
ing, alternator)
- Test voltage supply and wiring
=> Page
4
xxx.x g/s
Air mass
min.: 3.0 g/s
max.: approx. 150 g/s
3.0....5.0 g/s
If readout does not match
specification, see table for
display zone 4 => Page
46
Fault remedy
36
76
Fault remedy
46
46