Porsche 928 Workshop Manual page 576

928 54
928 GT
Fuel System - Electronic Control
24128
Test point Description
Page
Precautions, Groups 24/28 ............................................................................................ 2
Important vehicle information, Groups 24/26 ............................................................... 3
Testing requirements, Groups 24/28 ............................................................................. 4
Control unit encoding.. ................................................................................................... 8
1
l :
4
5
6
7
8
9
10
11
12
13
14
17
ia
19
20
21
22
23
LH Fuel Injection System
Effect of faults (cross-reference list) .............................................................................. 9
Fault memory.. .............................................................................................................. to
Plug connections at LH control unit ............................................................................ 10
Power supply ................................................................................................................ 11
Idle speed contact.. ...................................................................................................... 1 1
Full load contact ........................................................................................................... 13
Engine temperature sensor II ....................................................................................... 14
Air mass sensor ............................................................................................................ I 5
Idle speed control activation ........................................................................................ 16
Oxygen regulation control, rich ................................................................................... 17
Oxygen regulation control, lean .................................................................................. 18
Open circuit at oxygen probe ...................................................................................... 18
Fuel injection circuit shut down ................................................................................... 19
Control unit faulty ......................................................................................................... 19
No power supply .......................................................................................................... 20
Ground and plug connections ..................................................................................... 21
Fuel pump voltage.. ..................................................................................................... .2i
Engine speed signal from EZK .................................................................................... 22
Injection valves I Control.. ............................................................................................ 22
Fuel pressure ................................................................................................................ 24
Intake system leaks ...................................................................................................... 25
Resonance flap valve .................................................................................................... 25
Fuel tank venting .......................................................................................................... 26
Alternator and voltage regulator .................................................................................. 27
Leads K and L ............................................................................................................... 27
Check Engine warning lamp ........................................................................................ 29
l
DME Diagnosing/Troubleshooting
Prlnted In Germany - XX& 1990
D 24120 - 1