Pyro hook up

[Magoo]

Spent time working on the truck today. The pyro hasnt worked since I bought the truck and the boost guage sits at -2lbs at idle. Turbo is an ATS and I think it has the waste gate, has a diaphram and rod connected anyway, and the guages are isspro. The pyro has a + which the yellow wire is connected. The other is red. Is this even hooked up right.? Thanks Magoo

 

[160k87F250]

My pyro is a Banks pyro, but the yellow wire is hooked up to the (+) post also. It seems the guage is hooked up right. Do you have a solid connection to the thermocouple?
John

 

[Mike]

Magoo,

I have ISSPRO guages also, I had installation issues with mine (self install but hey! ) and needed to contact ISSPRO direct, I talked with an engineer (yeah I know, freaky huh) there and we determined that the unit I bought was faulty. New unit arrives and I install it and still have no PYRO movement...... now I's got's some diggin to do right? I found that my power supply to the amplifier box was faulty. Once I got that fixed the PYRO worked and has worked ever since. I called ISSPRO back and they said, eh....... no big deal, just send us the old one back and we'll call it good. Look up ISSPROS website and see if there is a service number to call. I think the guy I talked to there was named John. Helluva helpful guy.

 

[Magoo]

Power supply to the amplifier box? Can I have that in English? Far as I can see there are just yhe 2 wire(yellow and red) and the go from the thermo coupler to the gauge. Did I miss something?

 

[argve]

The pyro does use Yellow and Red wires and most pyrometers don't use an amplifier - that's something that ISSPRO likes to do (they love to use a 4-20ma system).

Yes the Yellow wire is the positive wire and the RED wire is the ground - this is an industry standard for pyro leads. This is called a K type thermocouple it should have a brown outar sheath.

Ok first let's get some background on how a pyrometer works...

The probe is actually PRODUCING voltage that drives the gauge - yes you read that correctly... What happens is one wire is made of one type of material and the other wire is anther material. When these two metals are welded together and heat is applied they will produce a very very small voltage which when connected to the gauge head will complete the circuit. Now what you have is a complete circuit with voltage applied so current flows, the gauge head is nothing more than an amp gauge and the needle will deflect a certain amount which we read as temp. This is because the two metals will ALWAYS react the same way. You can do more reading about this by going to Google and typing in Thermocouple theroy it gets pretty deep a lot deeper than I have explained here - trust me this is pretty high level electronics theroy...

But for most of us what we need to know is this...

The system needs a complete circuit that has GOOD CLEAN SOLID wiring connections. So my first line of troubleshooting any thermocouple (pyrometer) circuit (either automotive or industrial) is checking all the connections. Take some super fine sandpaper and clean the connections where the leads from the pyro meet up with leads from the gauge and then again at the gauge head it's self. I like to use those green scratch pads from under the sink - they do wonders for this type of thing.

If that does not do it for you then typically is not the gauge head that is bad it will turn out to be the probe it's self. If you have a very accurate milli-volt meter you can check the probe by pulling it and hooking it up to your meter then applying some heat via a propane torch. But if you didn't know how a pyro worked before this post then you probably don't own a meter worth trying this test because meters that will read that accurate aren't cheap and most homeowners nor shadetree guys own them. So in that case I would just purchase a new probe and go from there... They can typically be gotten for far less than an entire new pyro system (gauge and probe).

 

[rancherman84]

can you use a probe from say napa on a banks gauge a get a correct reading?
or do you need to keep the probe and gauge the same make?

 

[argve]

Yep sure can - the thermocouples are interchangable as long as they are of the same type - as in replace a K type with a K type and not a J type in place of a K type or vise versa. You have a K type I can tell because of the wire colors that you mentioned so as long as you buy a K type thermocouple your good to go. Now the parts guy may or maynot know or understand what your saying when you mention K type but just make sure the wire colors are the same this is because thermocouples are made to an industry standard.

 

[Russ]

Ok first let's get some background on how a pyrometer works...

The probe is actually PRODUCING voltage that drives the gauge - yes you read that correctly... What happens is one wire is made of one type of material and the other wire is anther material. When these two metals are welded together and heat is applied they will produce a very very small voltage which when connected to the gauge head will complete the circuit. Now what you have is a complete circuit with voltage applied so current flows, the gauge head is nothing more than an amp gauge and the needle will deflect a certain amount which we read as temp. This is because the two metals will ALWAYS react the same way. You can do more reading about this by going to Google and typing in Thermocouple theroy it gets pretty deep a lot deeper than I have explained here - trust me this is pretty high level electronics theroy...

Thank you MR. Wizard I always wondered how that worked.

So how can you tell if the guage is bad or if its the probe?

 

[Mike]

Power supply to the amplifier box? Can I have that in English? Far as I can see there are just yhe 2 wire(yellow and red) and the go from the thermo coupler to the gauge. Did I miss something?

Here is what the pyro gauge/amp box look like.------>CLICK HERE. Sounds to me like you have one of the units that doesnt need the signal amplified.

Here is ISSPRO's contact info.----->CLCIK HERE

 

[argve]

Well actually Mike it's not that the ISSPRO need the signal amplified it's that ISSPRO utilizes a 4-20 Milli-amp converter - meaning that everything from the probe to the amp box works just like all other thermocouple systems on the planet but what ISSPRO does is they convert that mili-volt changes from the probe to a signal that will run between 4ma to 20ma. The reason for using a 4-20ma signal is because they can dial in the accuracy on the production line much easier and typically a 4-20ma system is a little more accurate over the long haul. Basically it's just another way to skin a cat.

Gary -

How to tell if the probe is the problem or the gauge head. Easy... grab your handy dandy notebook (oops sorry wrong kids show)... No grab your high end multi-meter or thermocouple meter (yes they make them) and measure the voltage from the probe. You can do this with it on the bench I can't remember the amount of voltage that your supposed to have but what I have done in the past with working on ovens and such is I just hook up my meter then fire the oven up - If I see a movement on the meter (change in value) as the oven heats up then I ASSUME the thermocouple probe is good so that means the gauge head must be bad. Typically I'm not standing there with egg on my face. Now you could hook the gauge head up to a power supply theroically but I doubt that you will find a power supply that is that clean and is capable of not over driving the gauge head. Yes they are out there but trust me none of us can afford one - that's a lab grade piece of equipement $$$$$. Seen one once but never used it (computer controlled) Seen it while I was at Delphi Delco Electronics a few years back in one of the labs.

 

[Mike]

Well actually Mike it's not that the ISSPRO need the signal amplified it's that ISSPRO utilizes a 4-20 Milli-amp converter - meaning that everything from the probe to the amp box works just like all other thermocouple systems on the planet but what ISSPRO does is they convert that mili-volt changes from the probe to a signal that will run between 4ma to 20ma. The reason for using a 4-20ma signal is because they can dial in the accuracy on the production line much easier and typically a 4-20ma system is a little more accurate over the long haul. Basically it's just another way to skin a cat.

Understood, I guess what I meant is that ISSPRO makes both styles. Amplified signal and non-amplified signal.

 

[argve]

yeppers

 

[Russ]

Cool, thanks for the info Travis.

 

[rancherman84]

thanks argve ,i knew we kept you around here for a reason

 

[Magoo]

WOW. Argve. Get out much? Just kiddin. I am a little embarased. I grew up in a garage. Dad owned his own shop till he passed away. I worked there for 30 years. Would a thought I learned something by now. i closed it and kept all the tools. One thing I did learn was ask if you dont know. last few years I realized there is a hell of a lot I dont know. Specially bout diesels. So any way thanks for the break down. I checked it and it looks like the problem is in the thermo coupler. The boost guage is wacky too so i will replace both guages and the coupler. Not impressed with either really. Any recomendations on a good set. In fact if my turbo only makes 7lbs or so why have a gauge past say 10 or 12? Just alot of wasted numbers and you would think you could get more accuracy if you sprread the numbers out more any way.