EGT polarity

[BigD]

Hi guys!

I need a sanity check here. I bought an EGT off the web and there are no specs for it. I thought that it'd be obvious which way it goes by what I see on the reading - some insane value one way (or 0) and a reasonable temp the other. But now I'm not so sure. One way the EGT reads 22c, the other way, 37. It's humid as a motherf... in my garage but the intake reads 25 and clt reads 26.. So it seems more logical that inside the exhaust header it'd be 22 and not 37 but... can someone confirm?

[rob@vems.co.uk]

What colour are the wires?

[BigD]

The VEMS leads are the typical green and white. The sensor leads are white, one has a red pinstripe, the other blue.



Thanks Rob!

[rob@vems.co.uk]

k-type wires are green and white - that's the standard.
t-type wires are red and blue and VEMS can't use them I'm afraid.

[BigD]

The product page says it's K type.

http://www.auberins.com/index.php?main_page=product_info&cPath=5&products_id=69

[BigD]

Just went for a small tuning session. I got 400-420c at idle, and around 650c at WOT (not redline but around 6k [red=7.5]). From what I read about t-types it should have melted down... plus the values seem fairly reasonable don't they?

[rob@vems.co.uk]

All I can go on is the ANSI and IEC colour codes from here: http://www.omega.co.uk/temperature/pdf/tc_colorcodes.pdf
You need to be talking to the people you bought the sensor from.

[BigD]

Thanks Rob, I will ask them. In what way would a t-type manifest itself in the readings? From what I was able to find about them, they have a limit of about 100c. And not only is VEMS getting values from mine, but the temps seem reasonable for the running conditions, which seem to be out of t-type range.

[rob@vems.co.uk]

Each thermocouple type is going to give a different voltage at any given temperature - what its telling you may not have any relationship to anything.
How did you calibrate it?

[BigD]

I haven't calibrated it yet per se, I'm working off a friend's settings. I believe he has the webshop sensor.

[rob@vems.co.uk]

well its worth putting the sensor in boiling water, and ice, that should give you an idea of how far off you are.

[BigD]

Just got a hold of their tech guy, he said the color standards depend on country, that for them more typical is red and yellow. But with their EGTs they use red for +ve and blue or green for -'ve. So looks like I guessed right (my 22c reading was red->green, blue->white).

I do still want to calibrate it now. Do I have to use liquid or is free air ok? It's just that I have a little hand-held thermometer that came with my thermostat but it's gas only.

A bit OT here but I don't want to start a new thread, might as well hijack my own... man I am falling more and more in love with EFI, it's so much fun to get all this going from bottom up and then configure/tune things, instead of trying to figure out which sensor in your OE setup is causing a misfire or code. My 3rd tuning attempt, engine's already feeling great (I'm blown away by the throttle response, engine's an S52 [aka M52B32] and it has better throttle response than my S38 M5 did).

I never got around to thanking you, Rob, so THANK YOU, all of your guides and various write-ups have been invaluable!

http://vimeo.com/13256849