Getting my pyro working

[TWeatherford]

The complete running truck I bought for the 6.9 in it already had a banks pyro in it, however it did not work in that truck and, unsurprisngly, doesn't work now that I put it along with the motor it was attached to into my truck. Wondering if there is anything to check or fiddle with, before I buy a new thermocouple and/or pyro? I would assume that not all thermocouples are the same, so I would need to get a correct one from banks? I need to get this thing working so I can bump the timing and turn the pump up a little, its pretty gutless.

 

[argve]

really there is only 2 kinds of thermocouple probes used on diesels

"K" type and "J" type. the differences is what temp range you are looking for

"K" type is for before the turbo
"J" type is for after the turbo

More than likely you will need a "K" type.

But before you go buying a new one make sure that the connections are clean and tight and have the correct polarity....

How a thermocouple works is as it heats up the probe will GENERATE a very small voltage (you have to have a very sensitive voltmeter to actually read it - most meter will not do this) then as the voltage is created and current flows the needle of the gauge will follow suit.

If cleaning the connections and making sure the wiring is in tact doesn't work then a replacement probe is in your future.

 

[TWeatherford]

Good to know. Mine is right before the turbo. Since it is aftermarket, and has a red and a yellow wire, I guess I'll try it both ways since I can't really tell which is negative and which is positive.

 

[xantusak]

Red and yellow wire is a K type. Red is typically negative (allways on US manufactured TCs), however on imprted TCs it might be backward. No damage will be done by changing polarity, it just will read incorrectly. I do not understand the logic of K before turbo and J after?? Why would anyone want to measure after turbo anyway? The turbine removes an unknown amount of energy from the exhaust (temp will drop) so the measurement provides pretty much useless info. Anyway, J is good up to 1380F so would be just fine before turbo, unless some engines are capable running beyond that without melting. The J type is prone to corroding one of the wires (the Iron one) and thus unreliable. Sometimes the connection needs to be checked and cleaned if the temp reading is out. If you need either a newTC or the reading unit (gauge), take a look at Auber Instruments webpage. They have some inexpensive instruments that are way more acurate then a round automotive gauge, plus they allow for a process control, which is nice. Can be used with any type of TC as well. I love mine, and it was less (less then half) then any round automotive pyrogauge I could find.

 

[suv7734]

Good to know. Mine is right before the turbo. Since it is aftermarket, and has a red and a yellow wire, I guess I'll try it both ways since I can't really tell which is negative and which is positive.

Red and yellow is a type "K" thermocouple. Red in this case is the negative and the yellow is the positive.
The Banks system has a connection about 16" from the end of the thermocouple where it connects to the thermocouple extension wires. The wires have lug connectors on them and are held together by a screw and nut. Remove the screw and nut and clean up the connectors with a scotchbrite pad or similar and re-connect ensuring the connection is tight and mechanically sound. If the thermocouple wires are rough then just cut off a bit and strip them and re-do the connections. ALL OF THESE CONNECTIONS MUST BE MECHANICAL, solder is not an option here.
I have a Banks system as well and the one time there was a problem with the pyro it was the connection there.
Hope this helps.

 

[Ice Czar]

I do not understand the logic of K before turbo and J after??

generally speaking one type of TC is selected over another to match the expected temperature into the sweet spot for accuracy for that TC
TC's and RTD's are not linear the further out of thier sweet spot the greater the offset required

these pyrometers are relatively simple devices given you dont really need several decimal places for measurements, there isnt likely cold junction compensation, you probably have few options for calibration or offset.
In control engineering its typical to have much more resolution, shielded probes, much longer runs and a whole lot more signal noise.

since I havent gotten my hands on one of these gauges Im just guessing

Why would anyone want to measure after turbo anyway? The turbine removes an unknown amount of energy from the exhaust (temp will drop) so the measurement provides pretty much useless info.

pretty sure you just answered your own question there
the amount of energy actually employed could be deduced from the temperature change
but Id gather the real reason most folks would employ it is verification of the "normal" temperature differential, that all is well.

 

[TWeatherford]

Wow, thanks for the helpful info. If I had to guess, I would have guessed red to be positive, so that saved me a few minutes. Also handy to know not to use solder, I might just have done that.

 

[argve]

Why would anyone want to measure after turbo anyway? The turbine removes an unknown amount of energy from the exhaust (temp will drop) so the measurement provides pretty much useless info.

I wouldn't want one after the turbo but they sell them so

 

[Mat J]

why do you not solder the connections?

 

[Ice Czar]

why do you not solder the connections?

a TC is based on the Seebeck Effect the conversion of thermal energy to electrical energy. This (typically) requires two different metals, adding a third creates an additional junction, you would still get a voltage measurement but have no idea what it represents.
TC basics (again)

 

[Mat J]

a TC is based on the Seebeck Effect the conversion of thermal energy to electrical energy. This (typically) requires two different metals, adding a third creates an additional junction, you would still get a voltage measurement but have no idea what it represents.
TC basics (again)

Thanks, just use regular crimp connections then?

 

[xantusak]

Thanks, just use regular crimp connections then?

No, unless you have crimp connectors made from the same material as each of the TC wires. Otherwise, every time you have a connection through different metals, you introduce additional TC junctions=> reading incorrect temperature. If the TC wire needs to be extended a special TC connector has to be used, it has screw terminals made from the same materials as the TC wires of that specific type of connector. Here is a link to a panel mount connector of K type.
http://www.auberins.com/index.php?main_page=index&cPath=7
Also, Omega engineering makes c$$ploads of this stuff in more variety then anyone can ever need, but typically their stuff is not cheap.

 

[xantusak]

generally speaking one type of TC is selected over another to match the expected temperature into the sweet spot for accuracy for that TC
TC's and RTD's are not linear the further out of thier sweet spot the greater the offset required

Well, Resistance Temp Detectors (RTD) are actually nearly linear. However TCs are completely nonlinear and really do not have a "sweet" flat spot. The signal has to be linearized by the equipment reading them. On top of this,TCs actually have a "not so sweet" spot where one of the metals becomes paramagnetic and the measurement is not so good. For K type it is aroud 300F, I think, and the J type hits this point around 1380F- which is actually the max temp. usability for the J type..

 

[Ice Czar]

sorry didnt mean to infer TC had a "flat spot"
the "sweet spot" matching would be"normal" operating temperature, the further above or below that the larger the deviation

not having gotten my hands on any pyrometer guages I made the assumption that the cheap seats have no offset and are simple analog devices, obviously there are some rather pricey units that are likely converted to digital for post processing providing an order of magnitude better accuracy.

RTDs are certainly better (as reflected in thier price) but again require some post processing depending on application, resolution and calibration

my experience is pretty much limited to:
Keithley 2700 Digital Multimeter & Data Acquisition System W/
Keithley 7701 32 channel Differential Multiplexer Module
Keithley 7708 40 channel Diff Mux Module w/ Automatic Cold Junction Compensation
Fluke 2176A 10 Channel Digital Thermometer
Digitec HT 5810 Thermometer

 

[Mat J]

ok thanks, im about to order an isspro and just wanted to make sure, for all I know it will come with stuff to connect it.