Ralley Gauges Pegged,What Gives?

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dogpro

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I started up my 71 340 duster yesterday after a couple month sit and the fuel gauge pegged full and the temperature guage went all the way to the right to H, what gives? A bad ground?

Lou
 
Not sure if ralley dashes run like the sweep gauges (don't know what their actually called) but there's a voltage regulated on the back that if it goes bad can peg the gauges. Don't know how to check it but that's an idea for you :D
 
Nope this is a SURE sign of a bad VR. I believe all of the ralley clusters have the VR inside the fuel gauge. If you drive the car, unhook both gauge senders to disable the gauges, otherwise you will shortly be replacing the gauge movements, if you have not already damaged 'em.
 
You didn't mention the oil pressure gauge. What did it do ?
The problem is most likely a faulty limiter which is inside the fuel gauge.
There isn't an easy way to temporarily disable the darn thing.
If you're willing to drive without working gauges you can disconnect all 3 senders.
You'll need to insolate those connectors. The one on the oil pressure gauge rarely retains its insolator.
 
I didn't notice the oil pressure gauge as it only ran for less than a minute and I shut it down as soon as I seen it. I wasn't happy so I walked away LOL.
 
Ground or VR, one or the other.
The oil pressure gauge isn't in the same circuit.
 
I just looked at the '70 and '72 diagrams, so unless it changed, (and I don't have a 71 diagram), all three gauges are supplied from the limiter.
 
an oil warning lamp operates on 12 volts. An oil gauge is on the same reduced voltage as fuel and temp' gauges.
 
If you don't have Rally gauges yes. But I'd recommend an aftermarket solid state replacement instead

If you have Rally gauges, it's built into the fuel gauge, and will require "surgery" to repair
 
TrailBeast said:
They are in the same circuit as far as power, but not regulated power that I have ever seen, right?
Click to expand...

RedFish said:
an oil warning lamp operates on 12 volts. An oil gauge is on the same reduced voltage as fuel and temp' gauges.
Click to expand...

67Dart273 said:
I just looked at the '70 and '72 diagrams, so unless it changed, (and I don't have a 71 diagram), all three gauges are supplied from the limiter.
Click to expand...

Ah, ok.
Duh, warning lamp vs bimetal gauges.:D
When all three are gauges then they all three run of the VR. (got it)
 
I'll service rally fuel gauge #91 before the end of this week.
6 years ago no other gauge service company would touch this gauge.
Most of them still wont. One website states "rally fuel gauge service comming soon".
Good luck to all.
 
x2 on RedFish. He did an awesome job on my Rallye gauges which were all fried. His solid state VR is a definite improvement over the factory.
 
RedFish said:
I'll service rally fuel gauge #91 before the end of this week.
6 years ago no other gauge service company would touch this gauge.
Most of them still wont. One website states "rally fuel gauge service comming soon".
Good luck to all.
Click to expand...
x3 on Redfish , there is another guy that fixes them in Canada mrheaterbox http://mrheaterbox.com/instrument_clusters.htm had all my gauges fixed there, but the best way I think is to get the solid state VR unless you are entering some concours show , the solid state vr ends the problem of the mechanical vr inside the fuel gauge .
 
Well I finally got to look at the car and as the gauges were going up I gave the front of the cluster a few whacks and everything came back to normal and I have driven the car 3 days in a row and seems to be alright (maybe it just wanted some attention! LOL) but by the explanations above it may only be a matter of time before it goes.

Lou
 
I would take what is happening now as a temporary stay of execution.
Redfish's IVR eliminates the rallye dash in fuel gauge voltage limiter for an affordable solid state external one with an updated limiter free fuel gauge. He also offers and exchange program so you can have a same day repair. http://www.demonivr.com/index.html


dogpro said:
Well I finally got to look at the car and as the gauges were going up I gave the front of the cluster a few whacks and everything came back to normal and I have driven the car 3 days in a row and seems to be alright (maybe it just wanted some attention! LOL) but by the explanations above it may only be a matter of time before it goes.

Lou
Click to expand...
 
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