StevenAg03

So a few times now i have went out in the morning to start the truck and noticed that the guage was reading anywhere from 200°-400°. this is after it has been sitting over night. start it up and the temps rise, like they would if it was sitting ~0 when i started it. They only way i can get them closer to normal is to unplugg the power from the gauge and reconnect it.

This brings up two questions.

1)Does the pyrometer work off of a change in resistance? Meaning, when you initially hook up the gauge, there is a certain resistance noticed by the thermocouple which is transfered to the gauge. From then on, any change in that resistance reflects a change in the reading of the gauge. With this said, if you plugged in the thermocouple while it was still hot, the gauge would read way low.

2) anyone had this problem? I have DiPricol gauges. Could it be a bad gauge? Everything is hooked up correctly. Also i have noticed that it seems as though my EGT's are lower then most people i talk to. at idle it is just over 200°

P.J

Check your ground (where is it grounded?).

Pyros are different, my Isspro had an "amp" box, the Di Pricols I have now are wired straight into the gauge.

Just over 200 at idle is perfectly normal.

StevenAg03

the power and ground are straight from the battery.

P.J

Oh, and mine reads 2-400 when shut off also. I just ran out and checked it, hasn't been run since yesterday afternoon and it's saying about 275*.

If it isn't supposed to do that, I guess I'll find out why too, huh?

StevenAg03

when you start it up does the temp drop down to around ambiant?

it seems like mine reads higher if i dont "reset" it. surely the temperature in the exhaust manifold isnt ~200* after sitting all night.

P.J

I never really looked at it while starting, I'll have to let you know.

Meanwhile, I still think it is normal.

StevenAg03

should the power wire for the pyrometer be connected to a constant power source? Mine is connected directly to the battery. In looking at the installation instructions it says to put it on the ignition side. the only problem i see with this is that when you power is interrupted and then reconnected, the temperature is reset to 0. this would mean that the gauge is actually reading a difference in temperatures from "ambient". Therefore if it is 40* outside and the gauge is reading 350*, then isnt the temperature at the thermocouple actually ~400*. using the same logic, if its 100* outside and it is reading 350*, the temperature at the thermocouple is actually ~450*. this leads me to believe that shutdown temperatures depend on outside temps.

does this make sense?

wcbcruzer

My pyro now and my previous one both read 200-300 degrees while the truck was shut down. I think that's normal. One was a Banks, one an Autometer.

P.J

Mine is hooked into a 12V ignition source.

I'm confused about your question on ambient temps. I look at it like this, I could care less what my actual outside temps are, as long as I know what is going on inside that manifold.

StevenAg03

i agree. however, the temperature inside the exhaust manifold is not zero degrees when you start the engine...it is closer to ambient temperatures...

P.J

It the amp must start over at zero to understand what the actual temps are, it may just be the way the gauge is designed?

I mean, it surely isn't 200* when I get in my truck (even though my gauges says so), but I am confident in the readings as I get going down the road, right?

jeeptjstud

my Di-Pricol gauge is the same way.......200-300 at startup. Now im wondering the same thing as my EGT's are usually in the low range.