Bosch L-jetronic Fuel Injection
Troubleshooting, Maintenance & Repair

Special thanks to John Allen for providing the content

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Introduction:


i - Table of Contents
ii - Table of Contents (continued)
iv - Introduction
v - Introduction (continued)


Diagnosis: Starter runs, engine will not start:


1 - Diagnostic process
2 - Air Intake System diagrams
3 - Diagnostic process (continued)
4 - Diagnostic process (continued)
5 - Diagnostic process (continued)
6 - Diagnostic process (continued)
7 - Diagnostic process (continued)
8 - Diagnostic process (continued)
9 - Diagnostic process (continued)
10 - Diagnostic process (continued)
11 - Diagnostic process (continued)
12 - Diagnostic process (continued)


Diagnosis: Starter runs, engine will not start when cold:


13 - Diagnostic process
14 - Diagnostic process (continued)


Diagnosis: Starter runs, engine will not start when hot:


15 - Diagnostic process
16 - Diagnostic process (continued)


Diagnosis: Engine starts then stops:


17/18 - Diagnostic process


Diagnosis: Engine idles too high:


19 - Diagnostic process
20 - Diagnostic process (continued)
21/22 - Diagnostic process (continued)


Diagnosis: Engine idles too low, or rough idle:


23/24 - Diagnostic process


Diagnosis: Hesitation:


25/26 - Diagnostic process


Diagnosis: Inadequate power & poor performance:


27 - Diagnostic process
28 - Diagnostic process (continued)


Diagnosis: Excessive fuel consumption:


29/30 - Diagnostic process


Diagnosis: CO value too high:


31 - Diagnostic process


Electrical diagrams:


32 - Electrical component location
33 - Ck coolant temperature sensor resistance
34 - Ck thermo time switch
35 - Ck air flow meter
36 - Ck air flow meter (continued)
37 - Ck air flow meter (continued)
38 - Ck voltage output to fuel pump @ relay set
39 - Ck voltage input to relay set from ignition switch
40 - Ck voltage input to fuel pump relay of relay set
41 - Ck input voltage to control relay of relay set
42 - Ck input voltage to control relay of relay set (continued)
43 - Ck output voltage from control relay of relay set
44 - Ck output voltage from control relay of relay set (continued)
45 - Ck output voltage from control relay of relay set (continued)
46 - Ck voltage signal from coil to control unit
47 - Ck ground circuit for control unit
48 - Ck ground circuit for control unit (continued)
49 - Ck ground circuit for control unit (continued)
50 - Ck air temperature sensor resistance
51 - Ck input to fuel pump relay of relay set
52 - Ck voltage @ auxiliary air regulator
53/54 - Ck full throttle contacts of throttle plate switch


FI Maintenance: 1500cc engine:


55 - Maintenance process
56 - Maintenance process (continued)
57 - Maintenance process (continued)
58 - Maintenance process (continued)
59 - Maintenance process (continued)
60 - Maintenance process (continued)
61 - Maintenance process (continued)
62 - Maintenance process (continued)
63 - Maintenance process (continued)
64 - Maintenance process (continued)


FI Maintenance: 2000cc engine:


65 - Maintenance process
66 - Maintenance process (continued)
67 - Maintenance process (continued)
68 - Maintenance process (continued)
69 - Maintenance process (continued)
70 - Maintenance process (continued)
71 - Maintenance process (continued)
72 - Maintenance process (continued)


Appendix: FI electrical system:


73/74 - Electrical system diagram
75 - Test specs
76 - Test specs (continued)