1. Make sure the ignition system is OK.
2. Check the power supply system.
3. Check up visually a condition of components of system of injection of fuel. If the cause of the malfunction after performing the above steps has not been established, then read the list of possible malfunctions of the fuel injection system and how to eliminate them, and also contact the workshop to print out the trouble codes registered by the control unit.
4. Check up a condition of hoses in which there is an air circulation. Check absolutely all air hoses, from the thick air intake hose to the thinnest, related to the low pressure supply system.
5. Make sure that the gaskets of the starting fuel valve, injectors, as well as the gaskets on the intake manifold mounting flanges are normal. A leak in the intake manifold leads to the entry into the system of «side» air. The amount of this air is not included in the parameters stored in the memory of the electronic control unit and leads to a malfunction of the system. Excess air leads to an uncontrolled lean air-fuel mixture. This defect is especially noticeable when the engine is idling due to fluctuations in the number of revolutions.
6. Make sure the fuel lines are secure and tight.
7. Check that the connection plugs fit properly and that the pins are not broken or bent. If necessary, spray the contacts with an aerosol to improve contact conductivity. Do not bend the contacts yourself.
Injection system components - check
Attention! When performing work on the KE-111-Jetronic fuel injection system, remember that the fuel system, even after the engine has stopped, remains under pressure for a long time. Therefore, when disconnecting the fuel line, always cover it with a rag to prevent fuel from getting into your eyes.
The following troubleshooting procedure applies only to work that does not require the use of special tools and instrumentation.
nozzles
8. Turn off the ignition.
9. Disconnect the fuel line to make sure fuel is getting to the injector.
10. Have a rag handy, as fuel is usually expelled from the fuel line.
11. Have an assistant operate the starter if no fuel comes out of the fuel line after disconnecting it. If fuel is released during starter operation, then the fuel line is normal and fuel is supplied to the injector. Therefore, it is necessary to check the nozzle itself.
12. Remove the nozzle. First remove the upper part of the intake manifold.
13. Place a container or place a rag to collect escaping fuel.
14. Remove the large diameter air hose located between the air-fuel mixture regulator and the throttle valve. This will provide access to the shut-off valve on the air mass meter (see illustration).
15. Disconnect the fuel pump relay at patch panel 10.
16. Jumper on patch panel 10 pins 48 (or 30) and 52 (or 87) using a piece of wire. The fuel pump should start working.
17. Push the gate valve a little by hand. The injector should inject fuel. The jet of fuel must be cone-shaped. If this does not happen, then try again, deflect the gate valve this time to the stop. In the same way, you can check the amount of fuel injected by each injector. When performing the specified test, insert all nozzles into measuring cups. Do not kink the fuel lines of the nozzles.
18. Deviate the gate valve by about 2 mm.
19. Do not remove the jumper on the patch panel until approximately 20 cm3 has collected in the first measuring cup (ml) fuel.
20. Compare the amount of fuel in the cups. The difference in volume should not exceed 2.5 cm3.
If this difference is greater, then swap the injector with a larger and smaller injection volume and repeat the test. If swapping the injectors does not help and one of the injectors is still injecting more fuel, then replace that injector.
If, after rearranging the injectors, the same result is observed, then the cause of this may be a clogged fuel line, due to which its opening has decreased or the fuel distributor is faulty.
21. Perform a leak test for closing the injectors. After turning off the fuel pump (remove the jumper from the relay patch panel) after two minutes of operation with the shut-off valve on the air flow meter open, no fuel should come out of the injectors.
Start fuel valve
22. Turn off the ignition.
23. Turn out the starting fuel valve and disconnect the power plug. Do not disconnect the fuel line from the valve (see illustration).
24. Turn on the starter so that the fuel pump starts and pressurizes the system.
25. Lower the starting fuel valve into the container, and connect to its contacts through the auxiliary wire.
26. Connect the free ends of the auxiliary wires to the battery poles, respectively, one to (+), and the second to (-). The valve should start injecting fuel, which should come out in a cone-shaped jet.
27. Perform a valve tightness test. To do this, turn on the starter again to pressurize the system.
28. Wipe the valve dry. Within a minute, fuel should not come out of it.
Fuel distributor
29. Run for about 10 seconds. engine or operate the starter to pressurize the fuel system.
30. Remove the air filter cover and remove the replacement filter element.
31. Disconnect the air hose attached to the mixture regulator and throttle valve.
32. Move the air volume flow meter shut-off valve all the way up. It should open with the same resistance throughout the entire opening path.
33. Release the damper. It should close and there should not be any resistance to closing it. Otherwise, the air mass meter must be replaced. If the shut-off valve is difficult to open, but closes easily, this means that the control piston is stuck in the fuel distributor.
34. Replace the fuel distributor.
Intake air flow meter
35. Warm up the engine or let the engine run while still warm for about 10 seconds. before performing the check.
36. Disconnect the air hose attached to the mixture composition regulator and to the throttle valve pipe, loosening the fastening clamps first.
37. Check air meter damper. The damper should be 1.9 mm lower from the top of the narrow edge of the funnel, when viewed from the side where the fuel lines are attached. The maximum allowable distance can be 3mm (see illustration 11.0c). If necessary, correct the flap position by bending the retaining wire spring. Do not bend the leaf spring.
38. Make sure that the damper does not cling to the wall of the funnel after adjustment. If so, center it by loosening the mounting screw.
After making these adjustments, check the idle speed and CO content.
Idle stabilization valve
39. Turn on the ignition and touch the valve with your hand. The operating valve vibrates noticeably. If this is not the case, then either the valve itself is faulty, or the electronic control unit for the KE-III-Jetronic fuel injection system (see illustration).
40. Check the valve. To do this, disconnect the power plug and connect an ohmmeter to the valve contacts. The device should show the presence of a slight resistance. If the ohmmeter shows infinite resistance, then this means a breakdown of the winding and the valve must be replaced.
If the valve is normal, then the cause of its failure may be a break in the power wire or a malfunction of the electronic system control unit.
41. Connect a tester with a diode bulb to the contacts of the disconnected valve plug to check the power.
42. Turn on the ignition. If the light comes on, it means that the valve is receiving power from the fuel injection system control unit.
Throttle angle sensors. Vehicles with manual transmission
An ohmmeter cannot be connected directly to the sensors themselves, especially since one of them is located under the throttle valve pipe. Therefore, only the power plug is disconnected and measurements are performed on the power wires of the sensors.
43. Idling sensor. Connect an ohmmeter to pins 1 and 2 of the plug. With the throttle in the idle position, the ohmmeter should show 0 ohms.
44. Slightly open the throttle. The ohmmeter should show infinite resistance (G).
45. Full load mode sensor. Connect an ohmmeter to pins 2 and 3. With damper in position «Full throttle» The ohmmeter should read 0 ohms.
46. Close throttle. The ohmmeter should show infinite resistance (G).
Throttle Potentiometer. Vehicles with automatic transmission
47. Disconnect the three-pin throttle potentiometer plug.
48. Connect an ohmmeter to pins 1 and 2. The ohmmeter should show 1.5-2.6 kOhm.
49. Connect an ohmmeter to pins 2 and 3. The ohmmeter should show 0.75-1.3 kOhm.
50. Open throttle. The ohmmeter must remain connected and show a resistance of no more than 3.6 kΩ.
Attention! The throttle potentiometer can be adjusted. However, after making appropriate adjustments, it is necessary to «tune» and automatic transmission. This setting is only done in the workshop.
coolant temperature sensor
AUDI 80 vehicles with KE-III-Jetronic fuel injection system are equipped with a dual purpose coolant temperature sensor. This sensor is also included in the ignition circuit (see illustration 13.0).
51. Connect an ohmmeter to one of the contacts, and connect the second output of the ohmmeter to «mass» (-), for example, to the cylinder block. The value obtained will depend on the temperature.
52. Check the received value with the chart data (see illustration).
Lambda regulation mechanism
Checking the functioning of the lambda regulation mechanism is quite simple. But this requires an adapter and an ammeter. The test can also be performed using a gas analyzer. Below is the procedure for checking with an ammeter. The check must be carried out with the engine warm.
53. Disconnect the plug of the corrector of the composition of the air-fuel mixture.
54. Connect the adapter, which you can make yourself from two appropriate plugs and a piece of wire, to the power wire and to the corrector.
55. Separate one of the adapter wires and connect it to the ammeter (milliamp range).
56. Start the engine and leave it to idle.
57. Write down the value shown by the ammeter.
58. Pull out the engine oil dipstick (probe). The current in the control circuit should increase. If this is not the case, then one of the lambda control components is defective. To clarify this, disconnect the plug of the lambda probe and connect the green wire leading to the electronic control unit for about 20 seconds to «mass» (-). If at the same time the control circuit current changes, then the KE-III-Jetronic fuel injection system control unit is working, and the lambda probe is defective. If the current in the control circuit does not change, then the control unit is faulty.
Attention! The main condition for the correct functioning of the lambda control mechanism is the correct idle speed adjustment.
The procedure for removing most parts related to the fuel injection system does not require detailed explanations. Explanations are needed only for removing the injectors, air supply hose and the upper part of the intake manifold.
Nozzles - removal
59. Remove the upper part of the intake manifold.
60. Disconnect the nozzle holder.
61. Remove the nozzle with pliers along with the insert. Do not disconnect the fuel lines so that dirt does not get into the nozzles.
62. Lubricate the rubber o-rings with gasoline before installing the injectors into place so that they go into place more easily. If you put the nozzle «dry», then it is possible that the sealing rings may be twisted and they will not provide the necessary tightness of the injector fit. In this case, the engine will run unevenly due to «suction» air, e.g. at idle.
63. Replace without fail damaged or brittle rubber rings.
64. Tighten the mounting bolts of the holder with a torque of 10 Nm.
The air supply hose attached to the air-fuel ratio regulator and the throttle valve nozzle is removed either partially or completely when performing many jobs.
65. Loosen the hose clamps on the air/fuel ratio regulator and on the throttle body (see illustration).
66. Loosen the other air hose clamps. These include: the air supply hose to the idle speed stabilization valve, to the air duct of the injectors. Remove these hoses as well.
67. Disconnect the EVAP valve.
68. Remove the air supply hose. When reinstalling the hose, be sure to put a strainer on the fuel mixture regulator. In this case, the convex side of the sieve should be turned up.
To remove the upper part of the intake manifold, you also need to disconnect the air supply hose.
69. Disconnect the cable «gas» and remove it from the counter support (see illustration).
70. Disconnect the throttle angle sensor plug.
71. Remove all other air hoses.
72. Turn out bolts of fastening of top of an inlet collector and remove it.
72. Replace the old gaskets with new ones before installing the intake manifold.
73. Tighten the intake manifold top bolts in two passes to 20 Nm.
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