Sorry Dave, I missed the part when you said that your gas gauge always reads empty. I just redid my Ralleye gauges a couple of years ago with with the removal of the IVR in the fuel gauge (here is how it works ) and added an external solid state one, MAD bypass, AMP gauge converted to VOLT gauge. You did not say if your oil pressure gauge worked, and remember that your AMP gauge is independent of the rest. Did you inspect the bulkhead connector yet? I would remove the cluster, inspect the breakage prone pins on the circuit board (disconnect the battery first) attach a long ground wire onto the cluster (due to the fact that the factory one isn't long enough to test while the cluster is hanging) , reconnect the battery, and take a voltage output test from the ivr circuit in the fuel gauge. I would test your temp gauge voltage with the key on ( when it reads correctly), and engine running. I bet its something wrong with the internal gauge IVR.
Temperature gauge does not work on my 1970 340 Duster ?
- Thread starter DaveM
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Just curious, do you have a gauge or an idiot light? If you have a gauge and the sender for an idiot light and visa versa that may present a problem.
There should be a ground strap from the rear passenger side head to the Heater fan nut on the firewall.
Logan
Well-Known Member
Maybe you could get her warm and with the engine running, flip the ignition switch off and back on before the engine stalls and see if it works then. I'm not familiar with the inner workings of the switch but it does seem worth a try.
Electrical troubleshooting can be very confusing and difficult. I usually do the kind of stuff you have been doing for awhile to see if I can score the easy fix. However, at some point you need to start over and pursue it in a very methodical manner.
Here is what I would do. This will involve pulling the dash loose and out some where you can test things.
Steps:
1. Turn on ignition and measure the voltage supply at the temp gauge. This is the voltage provided by the IVR. This should be about 5 volts. If this voltage is wrong or unstable, nothing else matters, it won’t work right.
2. Find the wire connection that goes to the temp sensor. If you short this wire to ground momentarily, the temp gauge should move towards full scale. If it doesn’t, the problem is in the dash.
3. Take the temp sensor and connect it to the temp sensor wire on the gauge with a piece of wire like step 2. Ground the body of the temp sensor to a ground on the dash. With ignition on the gauge should read cold. Boil a glass of water in the microwave and stick the temp sensor in it. The gauge should go up to about a normal reading for a warm engine.
4. If step 3 works, do it again with the sensor grounded to the car frame this time. This will determine if the dash ground is good to the frame.
Tired of typing for tonight. If this is useful to you, I will keep going.
Here is what I would do. This will involve pulling the dash loose and out some where you can test things.
Steps:
1. Turn on ignition and measure the voltage supply at the temp gauge. This is the voltage provided by the IVR. This should be about 5 volts. If this voltage is wrong or unstable, nothing else matters, it won’t work right.
2. Find the wire connection that goes to the temp sensor. If you short this wire to ground momentarily, the temp gauge should move towards full scale. If it doesn’t, the problem is in the dash.
3. Take the temp sensor and connect it to the temp sensor wire on the gauge with a piece of wire like step 2. Ground the body of the temp sensor to a ground on the dash. With ignition on the gauge should read cold. Boil a glass of water in the microwave and stick the temp sensor in it. The gauge should go up to about a normal reading for a warm engine.
4. If step 3 works, do it again with the sensor grounded to the car frame this time. This will determine if the dash ground is good to the frame.
Tired of typing for tonight. If this is useful to you, I will keep going.
Thanks, I added a ground strap (red positive battery cable) from the bell housing bolt/engine block up to the firewall. No help ! Is it really worth trying another ground from the engine block now to the frame?
No, one ground strap is enough. The body and frame are the same on a unibody car.
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I will try steps 3 & 4 as you suggested, maybe another discreet ground to the dash is needed? thanks will keep you posted.
Sorry, misunderstood your question. My instructions are probably not very clear. What I was trying to do was eliminate as many things as possible from the circuit. I was wanting you to take a pice of wire ( only temporary) from the bolt on the back of the temp gauge that goes out to the sensor and just ground it to the dash ground. Just touch it to the gauge bolt and ground to see if the gauge works.
If the gauge goes up when you do this, you know at least that much of the circuit works. Divide and conquer. Then you move the temporary wire from the dash ground to the body ground & see if it still works. The sensor in the block works by grounding the gauge with different resistances when the temp of the engine changes.
With my procedure I am just trying to bypass parts of the circuit till we see where it stops working.
If the gauge goes up when you do this, you know at least that much of the circuit works. Divide and conquer. Then you move the temporary wire from the dash ground to the body ground & see if it still works. The sensor in the block works by grounding the gauge with different resistances when the temp of the engine changes.
With my procedure I am just trying to bypass parts of the circuit till we see where it stops working.
When I say dash ground I mean the ground on the circuit board on the back of the dash.
Hello where is the instrument cluster voltage regulator located?? It is not attached to the back side of my instrument panel? Is it inside the panel? Or somewhere under the dash or on the firewall? Any help would be appreciated. thanks in advance.
They are installed on the back of the instrument panel. It should be a small, rectangular metal box, about an inch or so long by about 1/2 inch or so wide. They varied through the years, but that is a good starting point.
I checked the panel, there is no regulator attached, just the printed circuit board with alt connections (large red & black wires) and center plug with (8 wires) and a capacitor connection. Is it located inside the panel?
Look at photo number 4,5,6,11and12
Also notice the condenser (VR capacitor )
MOPAR1970-76 PLYMOUTH DUSTER/DODGE DEMON DART DASH CLUSTER GAUGES 340 360 71 72 | eBay
Also notice the condenser (VR capacitor )
MOPAR1970-76 PLYMOUTH DUSTER/DODGE DEMON DART DASH CLUSTER GAUGES 340 360 71 72 | eBay
thanks but I have a rallye dash / instrument panel. there is no regulator attached on the back side.
Just looked at a ralley dash on ebay, im stumped.
thanks....4spdragtop states it might be inside the fuel gauge ? (so thats why I cannot see it on the back side of the dash)
voltage limiter is in the fuel gauge in a ralley dash .
thanks I will remove the printed circuit board for the gauges and locate the regulator inside.
it will look like a set of contact points . what I did when I had to disable it I put a piece of di electric plastic ? between the contacts instead of bending the points like mentioned in these directions and I used the rte limiter everything works good now .
RTE Gauge Faq - rte
RTE Gauge Faq - rte
You don't remove the circuit board. Remove the bezel from inst' housing. Remove fuel gauge from housing. Notice a small piece of metal on the back of that gauge. Also notice a unpainted spot on the housing under this gauge. All of this is to chassis ground the limiter inside the gauge. So... put a piece of electric tape over that piece of metal to isolate the OEM limiter from ground. Reinstall gauge Now it sits in the housing just like any 2 post thermal gauge. ( you can lift one of those to verify they aren't chassis grounded if you want ).
Remove the 12 volt wire ( blue with white tracer ) from round harness connector. Route this wire to wherever and whatever alternative regulator is installed. Route that regulators 5 volt output wire to any one of the 3 thermal gauges where the printed circuit board conducts the 5 volts to all 3 thermal gauges. Chassis ground the alternative regulator and you're done.
The OEM limiter, once isolated from positive and negative sources, becomes dead weight. It can't do squat. Regardless what RTE and others state, no one ever needed to open the gauge to substitute the 5 volt supply.
Oh and by the way... There have been a few cases where the rally fuel gauge got a bit loose at its mounting nuts. If the ground path at gauge to housing is broken the limiter stops working. Sometimes just scratch cleaning and tightening the gauge to the housing is all that's needed. Of course the housing must be chassis grounded to the car. It aint gonna work if dangling from harness connectors.
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this is what I was thinking and makes perfect sense but I put a piece of electrical insulation between the points to be sure because I did not want to destroy the original limiter like RTE says to do .
The downside of not opening this gauge is not knowing the condition of the gauge part. Due to the age and the duty cycle of the fuel gauge over 50 years, Most of them are toasted.
I rode that wagon for about 8 years. Opened over 100 rally fuel gauges. Majority of them needed more than just limiter disable. So I totally removed the limiters, renewed the gauge part as needed and calibrated to a solid state regulator. I still have a few 15 dollar cores here that I have yet to open. I pretty much know what I would find inside. There's currently a parts wanted post for good known working rally fuel gauge. That is as rare as hens teeth. Good luck to all.
Hello, I checked the voltage on all three sending unit leads, i.e. temp, gas and oil pressure.
At each lead the voltage seemed to vary, wildly from a top range of 8 volts down to 0 or tenths of a volt?? Again remember the oil pressure gauge is the only gauge that works, my temp & gas gauge do not. Is the voltage supposed to be a solid 5volts on each of the sending unit leads? If the limiter is defective then why does my oil pressure gauge work?
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