New Temp and Fuel Gauge Problem

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1969VADart

1969VADart

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i finally got the new dash and engine harness installed in my car. The car started up fine and the modulation that I was having at the ammeter and in the electrics in the car are gone. But I have another problem that has me at a loss. I replaced the fuel and temp gauges that were both burned up and I put a new solid state IVR in the dash. However when I turn the car on, the needles on the two gauges are constantly bouncing. But there is no bounce in the ammeter. I also replaced all of the nuts on the back of the cluster with real nuts, not those push in style, and I added an extra ground wire to the underdash from the two circuit boards. Any ideas what might cause the two gauges to bounce even with all the new stuff? Might order a traditional style IVR to install and see if that makes any difference.
 
If both gauges are bouncing then I would try another IVR. You might have a defective one.
 
Yeah, both gauges are bouncing in rhythm. But there is no other modulation through the dash, lights or ammeter.
 
Only the temp and fuel gauge use the IVR. My OE mechanical has a capacitor attached to its output. Most likely to smooth the pulsed DC from the mechanical IVR. Perhaps you left it in or out? and the electronic IVR is needing or not needing it.

My guess is that you have a bad IVR.

The mechanical ones have worked fine for 50+ years new is not always better.

When you say you replaced the fuel and temp gauges is that with OE gauges or aftermarket? I recall seeing that the aftermarket have specific power and sending unit requirements.
 
I replaced the gauges with whatever is supposed to be a direct replacement for the OE. I think I bought them from Classic Industries, but I can't recall for certain. My cluster also has that little capacitor with a single spade terminal on it. It is plugged into one of the sockets that the IVR plugs in. Guess I will start with a new IVR first and then see what happens.
 
1969VADart said:
I replaced the gauges with whatever is supposed to be a direct replacement for the OE. I think I bought them from Classic Industries
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Look at clasic's website. Im pretty sure they say somyhing anout ivr and senders
 
Dana67Dart said:
Look at clasic's website. Im pretty sure they say somyhing anout ivr and senders
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You are right. I checked Classic's website this morning and went ahead and bought one of the IVR's they recommend with the gauges I bought. Guess we will see what happens. Thanks.
 
Hope I didn't send you down a rabbit hole. Let us know how it works out.
 
first thing I would try is remove the noise suppression cap'. A solid state regulator doesn't make noise so the suppresser isn't req'd. Some of the very fancy aftermarket IVRs have fault sensing and that just might be your case. thinking maybe the cap' is seen as a fault. Some also have LEDs that blink or stand on to show faults ( if you could see the LEDs ).
 
RedFish said:
first thing I would try is remove the noise suppression cap'. A solid state regulator doesn't make noise so the suppresser isn't req'd. Some of the very fancy aftermarket IVRs have fault sensing and that just might be your case. thinking maybe the cap' is seen as a fault. Some also have LEDs that blink or stand on to show faults ( if you could see the LEDs ).
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I was not aware of that, but it is easy enough to test that theory out. Thanks.
 
So I installed the IVR recommended by Classic Industries. I tried it without the suppressor plugged in and the gauges did not work at all. So I plugged the suppressor back in with the new IVR and they seemed to work. Now the only thing that has me stumped is the temp gauge seems to read hotter than the old one used to read. I was reading halfway on the gauge and the car had not even reached operating temperature yet. The needle never tracked all the way over to hot, but it did stay close to just passed halfway on the gauge. The fuel gauge seemed to work, but it never read exactly correct and I am not even sure how much gas is in the car. But at least the needle did pick up. Guess I will give it a go like this and see what happens.
 
The 12 volt supply to the limiter or regulator is the center spade. Could be that without the additional spade of the suppressor poked in that female connector you didn't have connection. The originally limiter did have heavy gauge metal spades to support its weight. I don't know what a aftermarket regulator is made of. I do know the female connectors are simply clipped into the circuit boards. If one was stretched a bit from having 2 spades in it....
Why the gauges read differently....I don't know. Crusty old gauges would have read a little low.
 
RedFish said:
The 12 volt supply to the limiter or regulator is the center spade. Could be that without the additional spade of the suppressor poked in that female connector you didn't have connection. The originally limiter did have heavy gauge metal spades to support its weight. I don't know what a aftermarket regulator is made of. I do know the female connectors are simply clipped into the circuit boards. If one was stretched a bit from having 2 spades in it....
Why the gauges read differently....I don't know. Crusty old gauges would have read a little low.
Click to expand...

Interesting point about crusty old gauges. Maybe the new gauges just read correct. I know the car wasn’t running hot, so I will give it a go with these gauges and see what happens. I will say the new IVR did seem a little flimsier than the older version.
 
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