i noticed with this autometer pyro that when i turn on my headlights that my exhaust temps drop about 25*. i've tried swapping the power to the battery directly, and tried many different ground connections... what gives?

 

Now make sure your ground is good........ether than that...I don't now

 

i've already tried a bunch of different ground points... i'm posting another thread maybe they are related.

 

engine and body grounds.
Clark

 

One of my buddies first gens has guage problems related to headlight use. Whenever he turns his headlights on all of the guages on his dash rise about 15% or so. You can turn the lights on and off and watch them go up and down. Fuel, charge, temp all move. His electrical system was "rebooting" itself like he turned the key off and on the whole trip. Then it never did it again . . .

I just write it all off to Dodge wiring combined with a slight voltage drop from headlight use. I doubt 25 degrees is much of an issue. If you're really running at the ragged edge, just run 25 degrees more conservative

Chass
ct

 

Mine does the same thing, but it's closer to a 50* drop. Not enough for me to take the effort to fix .

 

I noticed the same condition with my Autometer Z series pyro I installed today, I double checked all connections with no change. Then I removed the bulb socket from the housing and toggled the dash lights on and off with no change. The needle moves about 1/8 inch just buy sticking the lit bulb into the housing, not even contacting the housing, just far enough in to illuminate the face of the guage. Just to be sure I tried to replicate this condition on the bench using a 12v jump box, and it did the exact same thing completly disconnected from the truck. Are the internals of these units sensitive enough to adjust readings due to heat from a tiny bulb, and if so how can this happen instantly? Is anyone here schooled in the internals on these guages? In any event I wont let this glitch stop my first round of mods.

 

The current that the light draws is causing a slight voltage rise in the ground wire going to the guage. Try running a larger ground wire to the metal part of the guage chasis (if there is metal) and see what happens. If that doesn't work maybe you could run a larger ground wire right into the guage (if you can get it apart and feel like living on the edge) and connect it to the ground at the base of the bulb. Or maybe you could replace the bulb with a lower ampacity bulb, like an LED bulb?

JP.

 

I have the autometer pyro. I finally wired it directly to the Batt posts put in a switch and fuse. It still bounces after a while and will eventually stop reading. I turn off the switch wait and turn it on it works for a while.
Not handy, I think I need a different gauge, mabey there is a more "heavy duty" version. When I bought it I was told this is the ticket.
Do all brands sometime act this way?

 

Get a direct reading non-electrical gauge and voltage will not effect it at all.

 

I know Autometer was having some issues with bad probes, they were covered under warrantee, but I can't remember which series gages, I have the Phantom series and they were not included in the probe issue. As far as direct reading gages every pyro I have seen is an electrical gage due to the probes. Putting a switch in line with the gage will affect the accuracy. The gage and probe are calibrated to work together without any modification to the intended wiring. Any lengthening, shortening, or any other modification will change the calibration, that’s why different probes will not work on different brand or series gages.

 

Ggg i think your point about the probe is correct.
My switch is not between the probe and the gauge. The gauge is electrical and needs a power source. My switch is to interrupt power to the gauge, not the probe. Hooked up per instructions the ignition switch becomes the on/off switch., don't see how my switch would be different than that. I actually tried it for a while direct with no switch or fuse still no good.
Sorry to hijack the thread.
Thanks
May have to just get a new probe

 

Mine is an electronic probe but not the same as some I have seen, mine reads even with the ignition turned off. Some are true electronic with an electronic gauge that relies on power from the ignition to operate. There are some total mechanical gauges out there because we had one on a Western Star tractor we had at work, used a probe kind of like a water temp gauge.