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post #1 of 5 (permalink) Old 09-29-2019, 09:55 AM Thread Starter
 
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Dash gauge calibration?

Looking for suggestions... My dash gauges are somewhat, not all, functional.. I think.. Temp gauge seems to be close I think, oil pressure looks to be OK, I think.. Fuel gauge only shows 1/2 full when filled. RPM gauge sticks and does not move much at all. It appears to be stuck somewhat. When I tap on the gauge window it does move a bit. BTW whats the manual RPM dial for? Speedometer is close but not accurate.. I notice the inside of the gauge panel has quite a bit of dustiness I assume from years of firewall insulation degradation.. The insulation is nearly all absent. Is there anyone who has had this situation and what was done to fix them all? Pull the dash clean it up and calibrate each gauge? She's a 1965 GTO all original and I aim to keep it that way.. As you might assume, nowhere to go to find any experienced mechanics with any working knowledge for this. Any suggestions are much appreciated
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post #2 of 5 (permalink) Old 09-29-2019, 11:01 AM
 
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Originally Posted by Sonoma GTO View Post
Looking for suggestions... My dash gauges are somewhat, not all, functional.. I think.. Temp gauge seems to be close I think, oil pressure looks to be OK, I think.. Fuel gauge only shows 1/2 full when filled. RPM gauge sticks and does not move much at all. It appears to be stuck somewhat. When I tap on the gauge window it does move a bit. BTW whats the manual RPM dial for? Speedometer is close but not accurate.. I notice the inside of the gauge panel has quite a bit of dustiness I assume from years of firewall insulation degradation.. The insulation is nearly all absent. Is there anyone who has had this situation and what was done to fix them all? Pull the dash clean it up and calibrate each gauge? She's a 1965 GTO all original and I aim to keep it that way.. As you might assume, nowhere to go to find any experienced mechanics with any working knowledge for this. Any suggestions are much appreciated

My suggestion would be to pull the gauges and send them out for a rebuild, thus keeping them original to the car. The manual red colored RPM indicator on the tach is to set where you want to shift, just a manual redline indicator.

Speedometer error may mean a change in rear-end gearing, taller tires, or different trans. The gear in the transmission can be swapped/changed out for a gear that will get you close to the correct MPH.

Fuel gauge may or may not be the problem. Often it is the sending unit in the gas tank, but keep in mind that the design/placement of the tank is not like our modern cars, so "accurate" is never really accurate.

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post #3 of 5 (permalink) Old 09-29-2019, 11:51 AM
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The 'manual RPM indicator' is called a tachometer. They are used by experienced drivers to determine optimal shift points and to monitor engine RPM. Peter Serio on the other forum can restore your gauges like new, Lectric Limited sells the correct sending units that are actually accurate. Like Jim said, the sending unit is the first place to look when the gauge indicates, but not accurately. If the guage is pegged either way, usually the gauge.
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post #4 of 5 (permalink) Old 09-29-2019, 01:03 PM
 
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Sometimes the speedometer will be so far off, the plastic gears you buy will not help.
Without going into the transmission, you can install one of these between your speedo
cable and transmission and fix the problem like I did. You will need to contact the company (PATC)
and they will sell you what you need based on 3 speedometer readings as opposed to your GPS.

https://www.amazon.com/PATC-speedome...42131849&psc=1
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post #5 of 5 (permalink) Old 10-03-2019, 10:18 AM
 
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North Hollywood Speedometer in California can rebuild and calibrate all your gauges. https://www.nhspeedometer.com/.
I had my speedometer rebuilt and my tach upgraded to work with a HEI distributor. They also have a service to restore the gauge face plates and dial indicators.
Speedometer rebuilding is around $250.00. There are other places around too I am sure, but I've used this company for years and know them to be good.
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