some Duster gauges not working?

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Matthew Sermini

Matthew Sermini

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Hey everyone so I am having a problem with my 1976 Plymouth duster. I just swapped in a 340 from original slant six and am having issues with the temperatures and fuel gauges not working. speedometer works fine, horn and all other lights work and i dont have any blown fuses. i don't recall if the lights on the fuel and temp gauges work or if they are out as well. any help would be appreciated because i know nothing about electrical stuff.
 
Matthew Sermini said:
Hey everyone so I am having a problem with my 1976 Plymouth duster. I just swapped in a 340 from original slant six and am having issues with the temperatures and fuel gauges not working. speedometer works fine, horn and all other lights work and i dont have any blown fuses. i don't recall if the lights on the fuel and temp gauges work or if they are out as well. any help would be appreciated because i know nothing about electrical stuff.
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Hey Matthew,

Common problems with A-Bodies.

Rather than hash through all the possibilities/solutions, Just type in Gauge problems in the upper right hand corner of the home page in the search box underneath your name. There are all kinds of problems /solutions listed there that should help you fix your problem.
 
Start by grounding the sender wires, turn the key to run, and see if the gauges head to the far right of the gauge.
 
IMHO. When both temp and fuel gauges don't work, it's the IVR, check the input voltage to one of the guages, should be in the 6v range or reading on a digital meter between 3 and 10 volts. A test light will also go from dim to bright if it is an original mechanical ivr.

Lastly if you do ground the sender wires and turn the key to on. If you see movement be ensure to turn off before it gets to about 1/2 scale or you could burn out your guages
 
after driving the car today for the first time this year, alternator gauge is out as well. does that mean it is still most likely the IVR? still not sure if the lights on the gauges work or if those are out as well. speedometer works fine though to confirm. radio seems to be out, not sure if that is related or not but just thought i would mention it. I won't be using it so its not a major thing needed to fix.
 
Matthew Sermini said:
alternator gauge is out as well
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Alt guages is not tied to the ivr in any way. BUT, if you had certain electrical issue I could see the alt guage not working causing the other guages to not work but I would expect the engine would not start either.

Sounds like it is time for an electrical diagram, and a lot of trouble shooting.
 
Dana67Dart said:
Alt guages is not tied to the ivr in any way. BUT, if you had certain electrical issue I could see the alt guage not working causing the other guages to not work but I would expect the engine would not start either.
Sounds like it is time for an electrical diagram, and a lot of trouble shooting.
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You are correct that the amp gauge is not related to the thermal gauges but...
The amp gauge in a 1976 model has a remote shunt. The small wires to this gauge are in the circuit board harness connector. So this model can have a good shunt and a bad gauge.
Sometimes with a engine R&R the chassis ground from firewall to engine doesn't reconnected. This can cause a variety of problems in different models.
 
RedFish said:
You are correct that the amp gauge is not related to the thermal gauges but...
The amp gauge in a 1976 model has a remote shunt. The small wires to this gauge are in the circuit board harness connector. So this model can have a good shunt and a bad gauge.
Sometimes with a engine R&R the chassis ground from firewall to engine doesn't reconnected. This can cause a variety of problems in different models.
Click to expand...
Dana67Dart said:
Alt guages is not tied to the ivr in any way. BUT, if you had certain electrical issue I could see the alt guage not working causing the other guages to not work but I would expect the engine would not start either.

Sounds like it is time for an electrical diagram, and a lot of trouble shooting.
Click to expand...

So do you guys have any recommendations on what I should do? i don't really know much about electrical stuff, but I would like to at least get my fuel and temp gauges working for obvious reasons.

I do have one question that i don't really know what this might affect but happened when i was doing my V8 swap. so I purchased an ignition kit from Jegs (I will link it) and i did not use the plug that goes into the ignition box because we didn't want to wire it when we already had the original one from the slant six. the only issue was that the slant six plug had one extra hole i guess and the new box had one less prong so right now there is something not getting power from the box. what does this affect? i hope someone understands what i am trying to say.

JEGS 40500K2: Mopar Ignition Kit Fits Small Block Mopar "LA" Engine 273/318/340/360 | JEGS
 
Ignition modules change from 5 wires and dual resistro to the 4 wire and single resistor years ago. That isn't related to gauges.
 
Matthew Sermini said:
so will that affect anything then?
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No. Like I said, the 5th wire and half of the dual ballast resistor was deleted. no longer required. The 5th wire just dead ends in the connector where there isn't a contact pin for it.
As for the gauges, I really don't know what to tell you. Your gauge voltage limiter is plugged in at very top center on the backside of the inst' panel. Pretty much impossible to R&R without pulling the panel out some distance. It is also throwing anywhere from 30 to 60 dollars at the problem without diagnosis. Doesn't help the amp gauge issue either. We could help you with diagnosis but first you must have a decent multimeter and a few jumper wires with alligator clips both ends.
 
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