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EGT sensor and wiring questions

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Old 09-23-10, 01:25 AM
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EGT sensor and wiring questions

I have a Westach dual EGT gauge...

http://www.pegasusautoracing.com/pro...asp?RecID=4861

...and two of these sensors from TCS...

http://tscsensors.com/egtep0720001ssnexhau.html

The sensors have 6' cables, but the instructions for the gauge say to use 4' cables. I didn't know before now that there would be an effect on readings because of cable length, so how much of a problem will the extra 2' cause? I could cut them down I guess, but I'm already concerned with how much length I will need to run them to the gauge.

Also, the wires from the sensors are red and yellow, and the instructions for hooking them to the gauge list the wires as black and white. Does anyone know which wire is which, or does it make a difference? I mean, should I hook red to white and yellow to black, or the other way around?

One more thing, I think I've read how deep the sensor is supposed to be into the manifold but I don't remember for sure. Should the tip of the sensor sit halfway into the manifold or how far exactly? Or does that matter at all? The sensors are mounted with NPT fittings btw, so it is adjustable.
Old 09-23-10, 04:40 AM
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red is negative
yellow is positive in EGT-land.

EGT leads DO have to be wired w regard to pos/neg. if they are reversed you will just get negative readings and will not damage anything.


don't know re length.

i suggest 1/3 into runner.

howard
Old 09-23-10, 02:42 PM
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Oh I should have mentioned I found that info online somewhere haha. The instructions for the gauge only mention white and black and where to hook them up. So I'm wondering if red goes to white and yellow goes to black or the other way around. But if it won't damage anything I guess I can just hook them up however and if it doesn't read right I'll switch them.

Thanks for the input Howard!
Old 09-24-10, 09:36 AM
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Length shouldn't matter. You just don't want to try to extend thermocouple wires with regular copper wire. That won't work.
Old 09-24-10, 11:38 PM
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Roger that, thanks.

I did get this installed today, and it works well. The gauge moves fast enough I suppose, works for me since I'm only using it for monitoring and not for tuning (I'll hook up the tuner's sensors when it's being tuned but I want to be able to monitor on a regular basis).

One thing I've noticed is that this Westach gauge DEFINITELY doesn't light up HAHA. I thought about it while I was trying to figure out the wiring but I didn't think it would be so bad at night. So I guess I will start looking for another gauge or get used to not seeing this one at night haha.

Oh, and if someone else wants to use this gauge, the wiring is as follows...

Posts 1 and 4 are positive (yellow, or white for Westach) and posts 5 and 8 are negative (red, or black for Westach).
Old 04-15-11, 02:25 AM
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I replaced this dual EGT gauge with a SPA Techniques dual EGT gauge today. The SPA sensors had the male mini connectors, similar to this...
http://tscsensors.com/mctmp600000000kmale.html
...so I took them off and put them on the sensors I already had, which were these...
http://tscsensors.com/egtep0720001ssnexhau.html

The sensors connected to the female mini connectors which then go to a little black box, which go to the wiring for the gauges. When I turned the car on I changed the reading from Celsius to Fahrenheit and the warning lights blinked for a few seconds. After they went off and after the car warmed up, the temps only got up to about 150*F. I'm going to read through the manual and see if there is something I can do, some adjustments that need to be made or something. But until then, has anyone else run across this problem?
Old 04-15-11, 02:04 PM
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I took the car to get an alignment this morning and noticed the gauges read in the opposite direction when you get moving. So basically when the temps are supposed to be going up, they actually go down. So when I got home I reversed the wiring (hooked yellow to negative and red to positive) and turned the car on, and it actually read in the negative. So I guess it was wired correctly, but there is something not right. And I didn't find anything in the manual. Anyone have any ideas?
Old 04-16-11, 12:35 AM
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Not all sensors are compatible with all gauges. Does the gauge specify a grounded or ungrounded sensor?
Old 04-16-11, 12:41 AM
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Yeah I was thinking they probably aren't compatible with each other. I'm not sure what the specs are as far as grounded or ungrounded, so I'm going to check and I'll post up what I find. Thanks!

Oh, I do know the sensors for the other gauges are supposed to be grounded, which I figure is probably why I'm having a problem with my water temp gauge acting funny, since I have it running into a brass elbow that is in a hose coming off the top of the engine and going straight to the water pump housing (bypassing the throttle body), so it's not grounded. I didn't realize that until today when I was reading through the manual.
Old 04-16-11, 12:52 AM
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Yep, if the temp sensor only has one wire and it's not grounded you will have all kind of problems!

I recently bought a thermocouple simulator that mimics the thermocouples output at different temperature ranges. It works fantastic for calibrating EGT amps to aftermarket ECUs.
Old 04-17-11, 12:35 AM
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Well the temp sensor has two wires, red and yellow. I do know that much, but I do not know if it's compatible or what would make it incompatible.
Old 04-17-11, 08:32 AM
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Does anyone have data sheets from tsc about the resistance to plug into the dataloggit? Wiring is easy not letting something know what to do with the new inputs is the hard part...
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