Firstgenfanatic

Ok, I just installed my gauges this Saturday (boost and Pyro). The boost installation was a breeze and turned out awesome. Both gauges are Isspro. The pyrometer has a "box" inline of the connection, an amplifier box. I hooked the pyro line from the thermocouple to the amp. box correctly and tested continuity to make sure. Everything checked out good. Next, I grounded the amp box to a metal frame piece under the dash (near steering column). I then ran the "ignition " power wire from the amp box to a "white-colored" wire on the fuse box. This white wire feeds to the "gauges" fuse. Once I started the pickup for the first time after installation this is what happened:

The pickup idled while the battery volt gauge cycled down and up (lights dim, then brighten). This has been the normal scenerio since I've owned the pickup. While the lights are dim and brightening, the pyro gauge is bouncing up and then down in conjuntion to the lights and volt gauge. Once the pickup stopped doing this (about 5 minutes later) I took it for a drive and fully warmed up the engine. The needle on the pyrometer gauge did not move at all! Nothing.........no movement what so ever. The needle sat against the little stop peg inside the gauge. I'm a little confused on why this gauge did not work.......but responded to voltage spikes while the engine was idling? Is it a bad ground? Maybe the thermocouple or amplifier box have problems? Or did I choose the wrong place to get my power source for the amp box? Any help would be appreciated.

flashgordon

I to have this same isspro pyro and have had it in for almost 2 years now.

It acts exactly as you describes, after a couple of minuets it straitens out and works fine all day.

I'm real happy with my gauge ether then that.


Flash

Firstgenfanatic

Only problem is that after those couple of minutes the gauge does not do anything........isn't working at all!

Firstgenfanatic

I forgot to mention that during my pyro gauge installation, one of the small connectors between the main pyro wire and thermocouple broke off. Not thinking much of it I soldered the connector back onto the wire. This was one of the connectors that comes together with small screws and lock nuts. I later read that Isspro claims that any soldering between the thermocouple and amplifier box with cause erractic readings. Could this have been my big mistake to a malfunctioning gauge? Isspro recommends a "crimped" connection on anything between the thermocouple and amp box. Hhhmmm..........

flashgordon

A ya im a fraid so.

there is a set lenth that cant be changed

dubble check you sodder joint to make sure is a 100% but i thing you will have to buy a new one, for that guage.

Flash.

Firstgenfanatic

I'm wondering if I should just melt off the soldered connection I made, clean it up and reattach a crimped connector? I did not shorten the wire or anything, just the little loop connecter broke off.

Chrisreyn

The length of the wires acts as a resistor and is preset.. anythign that changes teh resistance down the wire will alter the readings.....

Caver Dave

If this is the case, they must be adding resistance to the available 6', 8', 10', 14' & up to 75' lead wires to make them all the same?

Could the dimming/bright your seeing be the grid heater relays cyclingin/out? I used a different switched power wire (can check on the exact one, but pretty sure it wasn't "Gauges") and don't have any bouncing with any of the gauges...

Ace

I believe the way it works is the factory calibrates the gauge to go along with whatever length lead wire it is expected to be packaged with.

Just guessing here.

flashgordon

My pyro had a short lead that the instruction said it must no alter and then i bolted the extra lead to that to the guage.

You are going to need to call then and get the proper piece again......

Flash.

Chrisreyn

that's the way it has been explained to me..this thread touches on it:
https://www.dieseltruckresource.com/...ter+resistance

duracrap

If you don't change the length of the wires, then the resistance should not change. The only reason I can see for why Isspro calls for crimped connections is because the crimped connections are made of steel or Aluminum.

The solder is made of either Tin or Lead. These metals have a much higher resistance than iron, silver, or aluminum. I don't see how a crimped connection would change the resistance that much, as long as the connection is solid.

Firstgenfanatic

First off, nice avatar Second, I agree about the connection. I changed the way the wire is bonded to the connector, but the length did not change. Even if my resistances have slightly changed, I should at least see my needle move upward as the temp goes up (maybe not acurate, but the needle should move). My needle DOES NOT move at all. It seems to only move when the pickups cold and the volts are pulsating. It would be hard to believe that the thermocouple or amplifier box is broken.

6speedcowboy

I had that same problem on mine when I installed it. Even though the screwed connection from the thermocouple lead wires to the box wires was tight the connection wasn't good enough. All I had to do was barely loosen the screw and twist the connection and tighten it back up and I haven't had a problem since. Also check and make sure that you have a good ground connection and that another power source isn't interfering with it.

Your soldered terminal will throw the accuracy of the guage off, it will read low, but you should still get a reading.

BTW the lights going dim to bright is caused by the grid heater cycling.

Firstgenfanatic

I see! I thought the grid heater only works during the "wait to start" ? I guess it cycles while the engine is running?