Instrument gauge question

[widowmaker77]

So I’ve been restomodding a 66 for the last few years. Finally got it drivable and legal. Took it out this weekend and about 25 miles into my shake down trip my temp,oil pressure and gas gauge have maxed out. They have been doing fine with no issues then all of a sudden they pegged out. My cluster was re done by classy gauges, we ditched the amp meter and a volt meter was added due to running a 5.0 explorer motor. I’m running a centech harness also. I’m no electrical whiz but my first thought is since it’s all three gauges, maybe it’s a bad ivr??
Any help is appreciated.

 

[DirtDonk]

That’s the only logical explanation I can think of. Other than perhaps it became ungrounded?
If that’s possible, while still screwed to the housing.
If it was replaced with a modern version, the chances of it going bad so quickly go way up.

 

[widowmaker77]

That’s the only logical explanation I can think of. Other than perhaps it became ungrounded?
If that’s possible, while still screwed to the housing.
If it was replaced with a modern version, the chances of it going bad so quickly go way up.

Thanks I have an old one on a 77 gauge cluster. I’ll probably pull it off and test it to be sure it’s good before install it.

 

[Broncobowsher]

Bad IVR or bad IVR ground.

 

[widowmaker77]

Bad IVR or bad IVR ground.

Thank you! It is the only thing I can think of that’s common to all three gauges. Just wanted to be sure I was going down the right path.

 

[Broncobowsher]

If it was working and it changed to all gauges pegged, everything was installed correctly and something failed. The contacts inside the IVR welded, ground was lost, or the heater burned out. Modern new IVRs are not the best quality. Being you have a rebuilt set of gauges, I bet there was a new IVR. Worked perfect when shipped to you but had an early failure.

Yes, you were properly diagnosing it. Finding the common point that everything is connected to.

 

[widowmaker77]

It’s definitely a new one or either they used an old one from another vehicle. Not sure really. Most likely it’s new. I’ve seen a few posts saying these new ivr’s aren’t very reliable. Is there one any of you guys recommend that’s better quality than the others?

 

[widowmaker77]

Ok so it turns out the Ivr on my rebuilt classy gauges is an original type. I took the one off a set of 77 gauges and installed it on my 66. All three gauges pegged out. So I made up a ground wire and ran it to the little bolt that holds the Ivr on from the L shaped dash bracket and now all is good. Thanks everyone for the help!