I installed an Isspro EV series pyrometer about three months ago. I used their probe and I installed the amplifier box under my dash. I pulled power for the lights and the amplifier from the cigarette lighter. The three gauges and the amplifier are all grounded to the same location. The probe connections have heat shrink on them and the others were connected using a quality crimping tool and watertight connectors with the heat shrink. I connected them to the power source using t-taps for a better connection.

The first month I had it installed everything worked great. The second month the gauge started working sporadically and is now even worse. Sometimes it works and sometimes it doesn't. It will be working when I crank the truck and I can be driving and all of a sudden it will quit. It can be working when I shut the truck off and the next time I crank the truck it doesn't work. I've checked all of the connections twice and everything is good. I really believe it's something other than wiring. I don't know how to test the probe but I have one from my Bullydog monitor that I took off that I'm thinking of trying.

What could be causing this? Bad probe? Amplifier box? Is it ok to try the other probe? The fuel pressure and boost gauges work fine and the lighting on all of the gauges work without problem. I haven't contacted Isspro or Dieselmanor yet but I'm really starting to get frustrated. Thanks for the help

 

The same thing happened to me. I changed the probe all is good, on mine.

 

The other probe should work correctly if you're wanting to try it. I however would say your amp box is having issues only because the same thing happened to me once. But you're on the right track.

 

I tried switching to the other probe and the gauge still acted the same. I called DieselManor and without question he is sending me another amplifier box.

I asked if this was common and he said that failure is not common but that if there is a problem the amplifier is usually it.

I hate that it didn't work correctly the first time, but DieselManor was very easy and helpful in getting it replaced.

 

Those amp boxes are pretty picky. Glad Diesel Manor was good to work with, I usually send lots of ppl that way for gauges.