freek pyrometer gauge

[Artworks]

My pyrometer guage been freeky last few days. hit brakes, gage goes all way up. Signal light& needle dances with blinker. gauge reads 500 with truk idle cold. I hooked multi meter in line of power source & lead to gauge, I get 5 + Volts ( short. ) Leaving it disconnected . I contacted Kennedy where I purchased in 07. I wait for a reply. Any Ideas out there in the mean time ??

[Robyn]

The pyro uses only a small voltage generated from the thermocouple to drive the gauge.

If you are getting interference when the blinkers or ?? are on then there may be a short from the light circuit in the gauge or "??????

No outside voltage source is needed to run the pyro

RC

[Artworks]

My gauge came with a small 'control relay box' that is mounted lower firewall near steering column. When I first opened the gauge I wondered about it. I farmed in a past life and run turbo diesel tractors with pyrometers and never seen this type. The trans temp gauge also has a relay type box so it is getting busy down there !!! More little boxes & head aches they can cause!!!

[DmaxMaverick]

That box is the signal amplifier. Most later pyro's have them. Mine has one, and it's rock steady unless I'm transmitting on a 2-way radio (needle bounces all over).

If everything is wired correctly, sounds like you have some stray voltage or loss ground somewhere, probably a ground. Check the power source circuit. When grounds are lost, a component will ground where it can, including through other circuits, like your amp.

If the amp is powered from the brake or turn signal circuit, it might be as simple as a failed bulb (turn/brake).

[Artworks]

Well I got little time last night and did some more checking . I powered the gauge ( signal amp) right from battery, still registers 300 as soon as power is applyed, touch brakes, right up to 800 / 900, clean and even disconnected the ground, same thing. I have to pull the 'box' off and check for broken wires. But beginning to think the 'amp' is the problem. I contacted kennedy again to get his thoughts. Got to love thos little boxes of electronics , NOT!!!!

[stingthieves]

Are you sure all the electrical connections are tight?

[CareyWeber]

When the pryometer is doing that you can almost always bet it's a grounding issue. Clean and tighten all of your ground wires (BOTH ENDS).

[Artworks]

I checked the grounds 'but' maybe not good enough. When I get a little time, I am going to run a ground direct from battery and test the gauge. I have couple other things sharing the ground and they don't seem to be affected. We all know how illogical electric current can be sometimes.

[Kennedy]

If the box is mounted in the engine compartment I would suggest moving in-cab. We have very few issues with these gauges and it generally turns out to be wiring. I would definitely suggest isolating the grounds.

[Artworks]

Thanks all for comments . The 'Box' is on the firewall in passenger area left of steering,beside the trans oil temp 'Box'. Both are grounded to the metal bar / bracket running across & perpendicular to the steering under the dash. Very busy these days ( I am a carpenter at Prov. Park and also do contracting after hours.)So find an another ground source and isolate when time permits. Another Rainy day Job lol !!!!

[DmaxMaverick]

Moving the ground would be a good idea. It could be grounding through the brake switch, or even the IPC ground distribution. It also wouldn't hurt to add a bonding strap (ground wire) to the support, from the chassis. The pyro amps are also very sensitive to RF and EM interference, so make sure it isn't located near any electronic or solenoid component, or rat's nest of wires.

[Artworks]

Well I spent the last 2 hrs. trying to find problem, moving the box, ground power, checking wiresect. as soon as power is applied, the gauge moves and when running goes up to 900, appy brake, goes off the end, signals, and needle jumps around. The box must be crap. Every thing was working great up to a month ago ( installed in spring of '07.) I will contact manufacture and see about warranty ( Yea right !) more $ down whole. Why can't they keep things simple instead of electrical boxes that give nothing but trouble after couple of years.

[winemaker]

What is the brand of your Pyro? I have an Autometer Pyro and boost gauge. A mechanic buddy wired it up for me after I installed them.

Right from the get-go, the pryo was funky. With the headlights off, it was fine, but as it got dark and I turned on the lights, the needle vibrated. It would read what seemed acurately, but it would ocsilate very rapidly. Well, I took a road trip the next day up country, and after about 3 hours, the needle fell right off the shaft, where she's stayed for e year now.

I'd like to go get a new one, but I suck at electrical and those things aren't cheap, so I don't want to "experiment" with it.

By the way, it was installed as per the instructions with the probe installed into a new Heath crossover with bung, so I'm confident in that end of things.

If yours is Autometer too, I wonder if they have a problem?

Brett

[Artworks]

No, it is ISSPRO, I got it & Boost & Trans temp , 3.5 exhaust, Air system from Kennedy Diesel in spring of '07. Worked great till month or so ago.

[joed]

Have you checked the actual probe?

I had an Isspro Pyro that would act similar to yours when the probe was on its way out. Granted, it was the old style gauge, no amp box. Seemed like I could only get 2-3 years out of the probes.

Just a thought.

Joe.

[Artworks]

emailed Isopro, Curt from Issopro said that gauge has 2 yr. warranty , ( installed spring of 07 ), also to try and troubleshoot and gave number, which I called. Told Don (Issopro trouble shooter ) all the things I tryed. He figured that a component inside the amp was gone and need to replace amp ($40) I will contact Kennedy to order new amp I guess.