Microswitches
Posted: Wed Oct 08, 2025 11:29 am
Earlier in the year I replaced a microswitch.
On my car a cold start injector is activated if the engine is cold and the starter is turning and the hand throttle is up.
This microswitch is used to complete the circuit to the injector when the hand throttle is up.
I replaced it with a new one from Porsche after the pins on the old one kept coming loose.
As the weather turned a bit colder I became more aware that the car didn’t start very cleanly any more although it was fine after a little while.
I came to the conclusion that the cold start injector wasn’t working.
It would have been easy to replace it when I replaced the air box but less easy with it in place.
Before embarking on this I decided follow the manual about adjusting the microswitch.
Eventually I worked out that the switch worked the opposite sense to the original one.
Instead of completing the circuit when the flap was up it did it when the flap was down.
The old microswitch had only two terminals. The new one had four but the tabs were on the wrong ones.
I swapped them over and I happy to say that it all works like it should now.
On my car a cold start injector is activated if the engine is cold and the starter is turning and the hand throttle is up.
This microswitch is used to complete the circuit to the injector when the hand throttle is up.
I replaced it with a new one from Porsche after the pins on the old one kept coming loose.
As the weather turned a bit colder I became more aware that the car didn’t start very cleanly any more although it was fine after a little while.
I came to the conclusion that the cold start injector wasn’t working.
It would have been easy to replace it when I replaced the air box but less easy with it in place.
Before embarking on this I decided follow the manual about adjusting the microswitch.
Eventually I worked out that the switch worked the opposite sense to the original one.
Instead of completing the circuit when the flap was up it did it when the flap was down.
The old microswitch had only two terminals. The new one had four but the tabs were on the wrong ones.
I swapped them over and I happy to say that it all works like it should now.
