Air temperature switch

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11-21-2018, 12:03 PM

brinny

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Air temperature switch

on the rear of the right hand air box / filter housing, is an air temperature switch. Can you tell me how this may affect the running of the engine if not in perfect condition. Reason I ask is mine has a crack in the back and I will need to refit using gasket paste as both part and gasket are no longer available. Is it critical to the car or not so important? Many thanks for your assistance once more.

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11-21-2018, 12:52 PM

carsnplanes

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Quote:

Originally Posted by brinny

From what I've read on the engine management system, either for V12 or 6, the air temp can effect detonation, so with hot air entering the air box, the sensor will tell the ECU to slightly retard the timing to avoid pinging.

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11-21-2018, 01:47 PM

brinny

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Thanks. It wouldn’t prevent the car starting then? It would give me a clear sign if it was kaput by pinking?

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11-21-2018, 02:28 PM

carsnplanes

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Quote:

Originally Posted by brinny

Thanks. It wouldn’t prevent the car starting then? It would give me a clear sign if it was kaput by pinking?

No. A sensor like that is under the category of 'Correction" sensors. Primary sensors are TCD crankshaft position sensor for starting and flywheel speed sensor for running. I would check the TDC sensor as that is what signals the ECU for fuel.

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11-21-2018, 03:10 PM

brinny

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Right thank you. I don’t have a known problem but wanted to know what to look for and what it did as I begin the long journey of restarting the car. Now I know what it does and what symptoms are of this part failing. Much obliged.

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11-21-2018, 05:56 PM

VancouverXJ6

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You can check its function at idle, observe/hear the idle sound with and without it plugged in, you'll know.

https://www.britishparts.co.uk/jagua...mperature-p763

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11-22-2018, 12:42 AM

brinny

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Ok thanks.

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11-22-2018, 12:51 AM

warrjon

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There are 3 primary sensors for the Marelli ECU these are

TDC sensor on the front of the crank
Engine speed on the flywheel
MAP sensor which is inside the Marelli ECU

Correction inputs are

Air intake temperature switch - the one you are referring to on the right airbox.
Idle switch on the LH throttle body linkage
Engine coolant temperature on the right water manifold.

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