As its been chilly in the mornings now, when I start the truck I notice that my pyro jumps up to 1000* then back down to 200* then up to 1500*. I have noticed that it cycles with the grid heater. I thought it was a ground problem on the pyro so I temp. moved it to the frame and it still does it.

Any suggestions?
Michael

 

Any chance it is an electical issue caused by the system voltage drop when the heaters cycle on and off?
?

 

Your pyro is grounded? What sort of pyro do you have? Most pyros are a closed electrically system all of it's own. The 2 wires themselves generate a voltage based on temperature differences between the probe (in the exhaust) and the gauge (in the cab). Your gauge is just a sensitive voltmeter. I agree that this is some wierd electrical problem caused by the cycling of the grids. But your pyro shouldn't be grounded to anything. Maybe one of the pyro wires has shorted to ground. Maybe the probe is bad.

 

I think it is a drop in voltage as was mentioned, mine does the same thing if I am running to much stuff, the head lights with th driveing lights, radio,and heater, if I turn on the turn signal or any thing else like hit the brakes so the brake lights come on mine starts jumping as well, if I turn a few things off ,all is well.
I think your grids pull more juice than any thing .

 

Along these lines, how about taking off your battery cables and giving them and the posts a good brushing, could be a free fix to your issue?

 

I have a Autometer that had a similar problem. These pyrometers are extremely sensitive and because of that a good ground to the meter is paramount. When I e-mailed Autometer they suggested that I ground the meter directly to the block. I did and now it is rock steady, even when the heater cycles.

 

My Isspro pyro has done the same thing, but only when it is cold. It is only when i first start it, and then it jumps again when I turn the headlights on or when the grids cycle. I think I will probably try switching to a better ground and see if that helps.

 

My Isspro Has a seperate ground for the gauge and it doesn't move at all but seems that its the ones that don't have the gauge greounded that are having this problem

 

I had to also run the power side to a relay. When I would run with my trailer lamps on, mine would go haywire.

 

Thats exactly what its doing, once the grids stop its fine. I'll try grounding to the block.

Thanks for all the suggestions,
Michael

If it doesn't fix the problem I guess I'll just live with it.