Pyro gauge not working
Thread Starter
|
Senior User
Joined: Jan 2005
Posts: 289
Likes: 1
Pyro gauge not working
My truck came with boost and pyro guages when i got it, but the pyro never worked. Previous owner not around to ask.
I tested to be sure it is getting 12v, which it is, but that might be only to the illumination.
How can I diagnose what the trouble is with the guage?
brand is ISSPRO
Thanks
Ed
I tested to be sure it is getting 12v, which it is, but that might be only to the illumination.
How can I diagnose what the trouble is with the guage?
brand is ISSPRO
Thanks
Ed
Fleet Mechanic
Joined: Oct 2003
Posts: 1,764
Likes: 0
From: CentralEastern Utah
Their need to be two 12v sources. One should only power up when the lights are on for the back light. The other should have power when the key is on. Double check power. Also make sure the thermocouple is hooked up and connections are tight.
Elder User
Joined: Nov 2004
Posts: 798
Likes: 0
ED
Take off the two wires that come from the thermocouple to the gauge. Put a multimeter across them and see if you have a resistance reading. If not...the thermocouple is either open or the wires leading to it are open. If all of that checks out...then check the 12 volts that powers the meter. You can check that with the multimeter also. Just set it to DC volts and measure from the hot lead on the gauge to ground. If that's ok....next verify the ground wire is grounded. If all of the above checks out....then I'd say the meter is bad.
Take off the two wires that come from the thermocouple to the gauge. Put a multimeter across them and see if you have a resistance reading. If not...the thermocouple is either open or the wires leading to it are open. If all of that checks out...then check the 12 volts that powers the meter. You can check that with the multimeter also. Just set it to DC volts and measure from the hot lead on the gauge to ground. If that's ok....next verify the ground wire is grounded. If all of the above checks out....then I'd say the meter is bad.
Mountain Pass
Joined: Feb 2002
Posts: 224
Likes: 1
From: Northern IN
Most Isspro meters DO NOT use 12 volt to power the meter (except for the bulb so that you can read it at night). They use a self powered milivolt generator (thermocouple) that produces more voltage the hotter it gets, which drives the pyrometer gauge. I am not sure on the exact milivolt output of the thermocouple, but it can easily be read with a digital voltmeter that is calibrated to read milivolts.
Disconnect the two wires on the back of the gauge and connect your DVOM to these wires and start the truck. I would expect a reading somewhere between 50 and 750 milivolts, depending on how hot the exhaust temperature is. You can call Isspro if needed to get the exact specs on your thermocouple. If you don't get any reading either the wiring from the thermocouple is shorted or the thermocouple is bad and needs to be replaced. I seriously doubt that your gauge is faulty, unless someone tried connecting 12volts to it, and fried the inards.
Disconnect the two wires on the back of the gauge and connect your DVOM to these wires and start the truck. I would expect a reading somewhere between 50 and 750 milivolts, depending on how hot the exhaust temperature is. You can call Isspro if needed to get the exact specs on your thermocouple. If you don't get any reading either the wiring from the thermocouple is shorted or the thermocouple is bad and needs to be replaced. I seriously doubt that your gauge is faulty, unless someone tried connecting 12volts to it, and fried the inards.
Thread
Thread Starter
Forum
Replies
Last Post
