cyl head temp sender

[JFairman]

Would a VDO cylinder head temperature gauge sending unit work for megasquirt and other efi?

The instructions that come with the gauge say's you can put the sending unit on a spark plug or in a pinch under a cylinder head bolt or nut on stud.

EFI is so adjustable and programmable with a laptop it seems like it could be programmed to work with one of these.
http://www.egauges.com/vdo_indS.asp?Sender=Cyl_Head&PN=323-701

[turbo nut]

I use a stock 3.6 head temp sender wiwwth my MSIII. I use the Saab-Bosch from the drop down to calibrate it if I remember right. It was very close.

[jsveb]

Jf, just curious, are you going MS EFI?

[JFairman]

My cis works really good for what it is so I'll stay with it for now anyway. I like efi, even old analog L-jetronic and have had it in a BMW so who knows in the future..

I put in a VDO cyl head temp gauge the other day and wondered if the simple temp sender for it might work with or help efi for cold start afr accuracy.

[Midlife930]

The temp sensor you have looks to me like a thermocouple which will not work with EFI systems as they apply a fixed voltage to sensor with a resistance that varies with temperature. A thermocouple produces a voltage.

Dave

[JFairman]

You're right it is a thermocouple that produces a small voltage as it gets hotter and hotter. I have no idea how it does that but it does...

Anyway, I figured maybe some aftermarket EFI ECU's can be programmed to use that varying thermocoupler voltage instead of the return resistance or how much of the voltage signal from the ECU is returned to the ECU or grounded by the sensor.

[proffighter]

They produce a small voltage because of two different elements, look here:

Thermocouple application note from Pico Technology

[JFairman]

Thanks for posting that. I never looked it up.
The sensor is a copper ring with a leg and two wires crimped on the end.