Thermo Time Switch and the Air Temperature Sensor - fuel injection system

[LEO]

Hi everyone,

I have a few questions about the electronic fuel injection system, specifically regarding the Thermo Time Switch and the Air Temperature Sensor.

Does anyone know if it’s possible to replace the 35°C / 12-second Thermo Time Switch with a 35°C / 8-second version? What kind of implications or behavior changes would that cause?

Also, regarding the Air Temperature Sensor, I’m wondering if it’s possible to try using a more modern Bosch Engine Intake Manifold Temperature Sensor (part number 0280130039). Has anyone experimented with this or tried a similar setup?

Best regards,

 

[TomHom]

Hi Leo,
the 35°C is the value where both switches open (and stay open), i.e. not energizing the cold start relay any longer.
The 12s-second and the 8-second are the maximum time values for energizing the cold start relay at a temperature of -20°C.
The opening time between -20°C and +35°C will follow a curve defined by these values. Guess you never will start your engine at very low temperatures, so I would not worry about the fraction of a second.
To get an answer for your second question, just hold both temperature sensors in ice cold water, measuring the resistance. Then slowly heat up the water and compare both resistance values. If the values are the same at different temperatures you may use the other sensor.
Thomas