K-Jetronic is a mechanical system: the fuel is continuously metered in proportion to the quantity of air drawn in by the engine.
The K-Jetronic system was installed as Original Equipment in series production vehicles in the years 1973 through 1995.
Since then, the K-Jetronic system has been only of significance for repairs and maintenance.
Symptoms:
- Engine does not start/starts hard when cold
- Engine does not start/starts hard when warm
- Irregular idle during warm-up
- Irregular idle with warm engine
- Engine will not accelerate, backfires
- Engine backfires under load
- Poor Performance
- Engine runs on
- Fuel consumption too high
- Driving performance unsatisfactory
- CO concentration at idle too high
- CO concentration at idle too low
- Idle speed cannot be adjusted (too high)
- Engine starts but immediately dies
Symptom: Engine does not start/starts hard when cold.
| Oorzaak |
Remedie |
| Sensor plate and/or plunger not moving freely |
Check for free movement |
| Auxiliary air valve does not open |
Check valve for correct function |
| Electric fuel pump not operating |
Check pump fuse, pump relay and pump |
| Cold start system defective |
Check cold start system |
| Therm-time switch defective |
Test thermo-time switch |
| “Cold” control pressure outside tolerance |
Test pressure |
| Injector leaking, opening pressure low |
Check injectors on tester |
| Injected fuel quantities unequal |
Check for equal fuel quantities |
| Basic idle setting incorrect |
Check and adjust CO level |
Symptom: Engine does not start/starts hard when warm.
| Oorzaak |
Remedie |
| Leaks in air intake system (false air) |
Check air system for leaks |
| Sensor plate and/or plunger not moving freely |
Check for free movement |
| Air flow sensor plate stop incorrectly set |
Check and reset |
| Electric fuel pump not operating |
Check pump fuse, pump relay and pump |
| “Warm” control pressure too high |
Test pressure |
| Fuel system leakage |
Inspect fuel system for leaks |
| Injector leaking, opening pressure low |
Check injectors on tester |
| Injected fuel quantities unequal |
Check for equal fuel quantities |
| Basic idle setting incorrect |
Check and adjust CO level |
Symptom: Irregular idle during warm-up.
| Oorzaak |
Remedie |
| Leaks in air intake system (false air) |
Check air system for leaks |
| Auxiliary air valve does not open |
Check valve for correct function |
| Cold start valve leaking |
Check cold start valve |
| “Cold” control pressure outside tolerance |
Test pressure |
| Injector leaking, opening pressure low |
Check injectors on tester |
| Injected fuel quantities unequal |
Check for equal fuel quantities |
| Basic idle setting incorrect |
Check and adjust CO level |
| Lambda control system not functioning correctly. |
Check Lambda control system |
Symptom: Irregular idle with warm engine.
| Oorzaak |
Remedie |
| Leaks in air intake system (false air) |
Check air system for leaks |
| Sensor plate and/or plunger not moving freely |
Check for free movement |
| Cold start valve leaking |
Check cold start valve |
| “Warm” control pressure too high |
Test pressure |
| “Warm” control pressure too low |
Test pressure |
| Injector leaking, opening pressure low |
Check injectors on tester |
| Injected fuel quantities unequal |
Check for equal fuel quantities |
| Basic idle setting incorrect |
Check and adjust CO level |
| Lambda control system not functioning correctly |
Check Lambda control system |
Symptom: Engine will not accelerate, backfires.
| Oorzaak |
Remedie |
| Leaks in air intake system (false air) |
Check air system for leaks |
| Sensor plate and/or plunger not moving freely |
Check for free movement |
| “Warm” control pressure too high |
Test pressure |
| “Warm” control pressure too low |
Test pressure |
| Basic idle setting incorrect |
Check and adjust CO level |
| Lambda control system not functioning correctly |
Check Lambda control system |
Symptom: Engine backfires under load.
| Oorzaak |
Remedie |
| Sensor plate and/or plunger not moving freely |
Check for free movement |
| Electric fuel pump not operating |
Check pump fuse, pump relay and pump |
| “Warm” control pressure too high |
Test pressure |
| Primary system pressure out of tolerance |
Test pressure and adjust with shim |
| Injector leaking, opening pressure low |
Check injectors on tester |
Symptom: Poor Performance.
| Oorzaak |
Remedie |
| Leaks in air intake system (false air) |
Check air system for leaks |
| Sensor plate and/or plunger not moving freely |
Check for free movement |
| “Warm” control pressure too high |
Test pressure |
| “Warm” control pressure too low |
Test pressure |
| Primary system pressure out of tolerance |
Test pressure and adjust with shim |
| Injected fuel quantities unequal |
Check for equal fuel quantities |
| Throttle butterfly does not open completely |
Check butterfly and stops in throttle venturi |
| Lambda control system not functioning correctly |
Check Lambda control system |
Symptom: Engine runs on.
| Oorzaak |
Remedie |
| Sensor plate and/or plunger not moving freely |
Check for free movement |
| Air flow sensor plate stop incorrectly set |
Check and reset |
| Cold start valve leaking |
Check cold start valve |
| Injector leaking, opening pressure low |
Check injectors on tester |
| Basic idle setting incorrect |
Check and adjust CO level |
Symptom: Fuel consumption too high.
| Oorzaak |
Remedie |
| Cold start valve leaking |
Check cold start valve |
| “Warm” control pressure too low |
Test pressure |
| Basic idle setting incorrect |
Check and adjust CO level |
| Lambda control system not functioning correctly |
Check Lambda control system |
Symptom: Driving performance unsatisfactory.
| Oorzaak |
Remedie |
| Leaks in air intake system (false air) |
Check air system for leaks |
| Sensor plate and/or plunger not moving freely |
Check for free movement |
| Excessive fuel delivery to control circuit |
Check fuel delivery |
| “Warm” control pressure too high |
Test pressure |
| “Warm” control pressure too low |
Test pressure |
| Primary system pressure out of tolerance |
Test pressure and adjust with shim |
| Basic idle setting incorrect |
Check and adjust CO level |
| Lambda control system not functioning correctly |
Check Lambda control system |
Symptom: CO concentration at idle too high.
| Oorzaak |
Remedie |
| Sensor plate and/or plunger not moving freely |
Check for free movement |
| Cold start valve leaking |
Check cold start valve |
| “Warm” control pressure too high |
Test pressure |
| Basic idle setting incorrect |
Check and adjust CO level |
| Lambda control system not functioning correctly |
Check Lambda control system |
Symptom: CO concentration at idle too low.
| Oorzaak |
Remedie |
| Leaks in air intake system (false air) |
Check air system for leaks |
| Sensor plate and/or plunger not moving freely |
Check for free movement |
| Basic idle setting incorrect |
Check and adjust CO level |
| Lambda control system not functioning correctly |
Check Lambda control system |
Symptom: Idle speed cannot be adjusted (too high).
| Oorzaak |
Remedie |
| Auxiliary air valve does not close |
Check valve for correction function |
Symptom: Engine starts but immediately dies.
| Oorzaak |
Remedie |
| Electric fuel pump not operating |
Check pump fuse, pump relay and pump |
| Excessive fuel delivery to control circuit |
Check fuel delivery |
| “Warm” control pressure too high |
Test pressure |
| “Warm” control pressure too low |
Test pressure |
| Primary system pressure out of tolerance |
Test pressure and adjust with shim |
Bron: http://vwgolfmk1.org.uk/forum/index.php?page=topicview&id=fuel-systems-and_4%2Fk-jetronic-troubleshoot_2
