Audi 80 Quiz
Digifant Injection System

Fault Table - Digifant Injection System

In this manual: Digifant Injection System
Technical Description — 39Engines — 41Exhaust System — 13Cooling System — 28Fuel tank and fuel pump — 12Air Filter and Intake Ducts — 13Mono-Motronic Injection System — 18Digifant Injection System — 19KE-III-Jetronic Injection System — 35MPI and MPFI Injection Systems — 32Clutch — 11Transmission and Driveline — 21Suspension and Steering — 33Brake System — 41Anti-lock brake system — 8Wheels and Tires — 13Body Electrical System — 35Ignition System — 24Lighting — 14Signaling Devices — 7Instruments and Auxiliary Equipment — 54Heating and Ventilation — 7Body Components — 18Troubleshooting — 6Specifications — 13
~2min read

Malfunction Possible Cause Remedy
A. Cold engine does not start at all or starts with great difficulty 1. Faulty fuse 13, 21, 25, 27 or 28
2. Faulty fuel pump relay
3. Fuel pump does not deliver fuel at all or delivers very little
4. Cold start valve does not inject fuel or leaks
5. Faulty fuel pressure regulator
6. Faulty coolant temperature sensor
7. Faulty throttle valve potentiometer
8. Faulty control unit
9. Wiring harness between Hall sensor and control unit damaged
9. Unmetered air entering the engine		 Replace
Check, replace if necessary
Is there any fuel in the fuel tank at all?

Check pump, measure fuel delivery quantity
Check cold start valve

Measure pressure in workshop

Check in workshop

Check in workshop
Check cable continuity

Check all fuel lines
B. Warm engine does not start at all or starts with difficulty 1. Vacuum hose to fuel pressure regulator damaged
2. See A 2 – 9
3. Injectors leaking		 Check line

Check injectors
C. Engine starts but stalls again 1. Idle stabilization valve not working
2. See A7		 Check valve
Check function, replace if necessary
D. Cold engine shakes at idle 1. See A 6
2. See C 1
3. Automatic transmission control unit and throttle valve potentiometer are not matched to each other (only after component replacement)		 Carry out matching in workshop
E. Warmed-up engine shakes at idle See C1
F. Idle speed drops when steering wheel is turned fully See C1
G. Engine runs unevenly 1. Fuel filter clogged
2. See A3
3. See B3
4. See C4		 Replace the filter
H. Fluctuating engine speed at 2000–3000 rpm See A7
I. Engine runs unevenly and stalls See A3
J. Insufficient engine power 1. See A3, 7 and 10
2. See C3
4. Throttle valves do not move to full-throttle position		 Adjust accelerator cable
K. Backfiring in the intake manifold See A5
L. Fuel consumption too high See A6 and 7

Test yourself

A quick Audi 80 quiz: every answer comes with an explanation and a link to the manual page.