Fuel Injected CHT under #3, Question about FI and CHT Options

[nditiz1]

So I know that FI cars use the CHT from the factory to make the magic happen (IMG:style_emoticons/default/biggrin.gif) (you D/L-jet guys and your mysterious voodoo) , but do you guys also put an additional one under #3 for cockpit info purposes? Does the factory one shutdown the motor if temps get too high? (Now that would be cool)

[BeatNavy]

So I know that FI cars use the CHT from the factory to make the magic happen (IMG:style_emoticons/default/biggrin.gif) (you D/L-jet guys and your mysterious voodoo) , but do you guys also put an additional one under #3 for cockpit info purposes? Does the factory one shutdown the motor if temps get too high? (Now that would be cool)

Yes, if you want head temp info it is typical to use a sender (e.g., thermocouple) under #3 sparkplug. The CHT is actually located next to cylinder 3, and all it does is send info to the ECU for balancing mixture based on engine temps. It won't shut the engine down (as a safety), but it will shut down the engine if it fails in open mode (e.g., disconnected). The ECU will make the mixture way too rich at that point and essentially flood it.

[Mblizzard]

So I know that FI cars use the CHT from the factory to make the magic happen (IMG:style_emoticons/default/biggrin.gif) (you D/L-jet guys and your mysterious voodoo) , but do you guys also put an additional one under #3 for cockpit info purposes? Does the factory one shutdown the motor if temps get too high? (Now that would be cool)

Yes, if you want head temp info it is typical to use a sender (e.g., thermocouple) under #3 sparkplug. The CHT is actually located next to cylinder 3, and all it does is send info to the ECU for balancing mixture based on engine temps. It won't shut the engine down (as a safety), but it will shut down the engine if it fails in open mode (e.g., disconnected). The ECU will make the mixture way too rich at that point and essentially flood it.

As Rob said the factory ECU can not shut down the engine due to temperature. However, if you go to an aftermarket ECU you could program that in. But I would not think that would be safe unless it was for only track use. With Micro Squirt you can limit fuel based on temp. I have not looked into it but I would think that it would be possible to program the use of a different fuel/spark table that is used based Adding more fuel and reducing advance can quickly reduce temp and would be essentially a limp home mode that would not leave you stranded.