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Tempeture Sensor

EFI Wiring Fundamentals

Discussion and questions related to the course EFI Wiring Fundamentals


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Hello ,

I am looking at installing a engine oil temp sensor that will be used directly to the ECU (no gauge) . I was wondering would it be better to use a bosch sensor with 2 wires or use a tempeture sensor with a single wire similar to a gauge sensor ? I have seen a lot of racers use the Bosch sensor but what is the benefit of the Bosch (2wires) over the single wire sensor ?

What would be the ideal way to run the wires to a link pnp ecu ?

Thank you!

Dont use a single wire sensor, they are really only for gauges. The benefit of a 2 wire sensor is it is connected to the ECU sensor ground so the ECU is making its measurement based on the same reference ground. With a single wire sensor it is grounded through is body (chassis ground) so any small ground offset between the ECU and engine will throw the measurement off. For gauges it doesnt matter so much as they dont usually have very good resolution anyway and they often use a 12V pull up which reduces the potential ground offset effect compared to an ECU that uses a 5V pull-up.