Does anyone know why some vehicles use CHT(cylinder head temperature sensor) while others use ECT(engine coolant temperature)? Thx!

 

CHT is more accurate.

Say you lose coolant and the engine starts to overheat...well, with no coolant in the engine, there's nothing for the ECT to measure, so the readings may be skewed. The cylinder head is always gonna be there.

 

97-98 model years used an ECT Sensor and sender and also CHT sensor. Why did ford switch? Most likely because it was cheaper to do so. The ECT sensor was used as an input for the PCM to calculate fuel delivery and the sender was used for temperature indication on the instrument cluster. The CHT was used for FailSafe cooling. Ford got rid of the ECT sensor and sensor sometime in 99 and kept only the CHT for all three uses.

Regards

Jean Marc Chartier

 

Makes you wonder why Ford continues to show an inferred ECT on the dash, doesn't it? Why not just display CHT (and call it "Engine Temperature" if CHT confuses people)?

- Jack

 

So Ford uses some algorithm to infer engine coolant temperature from CHT for the 3 uses. How about Japanese cars and GMC? Do they also use only CHT? Is this a trend to only use CHT for cost saving?

 

I don't think it's cost savings so much as it is more "reliable" as inferred by Quintin in his post. If the coolant "boils" and an ECT sensor sees nothing but "gas", it will not transmit a valid temperature reading. Your engine might be melting and you wouldn't know it. (Not really, but you get the idea).

I have a Gryphon programmer in my truck and can monitor the CHT directly. It rises right with the "ECT" temperature gauge on the dash and stabilizes in the 200-202 degree range for most driving. If I'm really pushing the truck like in a long uphill climb in the desert pulling a trailer, I've seen the CHT get to 210-214, never higher.

I have no idea what other cars use, but this is a time when I think Ford got it right.

- Jack

 

so on my 2001 4.6 f-150 is there a ect? ... or a cht sensor?

 

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