Mercedes-Benz W126 K-Jetronic cold start injector
380 SE
How does the W126 cold start injector work?
The injector gives a cold engine extra enrichment only while cranking and only when the coolant is cool. The thermo-time switch gives it a control signal for about 8 seconds. When the key is released, the voltage disappears.
At what temperature does the W126 cold start injector stop working?
The limit is estimated at 40...50 degrees. On a hot engine the injector should have no effect unless it leaks. If unplugging the wire does not change how a warm engine starts, the fault is not in the injector.
How do you check that the W126 cold start injector works?
Remove the injector and aim the spray into a bottle. You can see how long it sprays. If the injector sprays while the engine runs with the plug connected, the fault is in the control. If the spray does not stop even after the plug is unplugged, the injector is faulty.
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