 Different voltmeter readings? |
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| SKL1 |
 Jul 14 2025, 08:44 PM
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#1
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Senior Member  Group: Members Posts: 1,717 Joined: 19-February 11 From: north Scottsdale Member No.: 12,732 Region Association: Upper MidWest 
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I've noticed with my '71, which has about 120K miles on it, the voltmeter is pretty much always reading around 11 V regardless of speed or revs.
In my '73, which has about 77K miles on it, it reads 11 or so at start up and for the first couple miles and then goes up to between 12 and 13. I swapped the voltage regulators for the heck of it and it didn't change anything. Is the older alternator from the '71 just worn out?? Not looking forward to changing it with the engine in the car!! |
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| SKL1 |
Jul 17 2025, 10:16 AM
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Senior Member Group: Members Posts: 1,717 Joined: 19-February 11 From: north Scottsdale Member No.: 12,732 Region Association: Upper MidWest
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My initial entry was a little simplified- I actually swapped engines in my '73 2.0. With the original engine the voltmeter in the console (OEM) would read under 12V at first when driving and would then, after a few miles, read over 12 or 13.
I put the modified engine from my '71 in the 2.0 and since then the voltmeter never even gets to 12V no matter how far I drive. That is why I wondered if the alternator wasn't working as well as the one in the 2.0 engine. Does this make sense?? (IMG:style_emoticons/default/smile.gif) |
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| GregAmy |
Jul 17 2025, 12:32 PM
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#3
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Advanced Member Group: Members Posts: 2,516 Joined: 22-February 13 From: Middletown CT Member No.: 15,565 Region Association: North East States
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QUOTE(SKL1 @ Jul 17 2025, 11:16 AM)  I put the modified engine from my '71 in the 2.0 and since then the voltmeter never even gets to 12V no matter how far I drive. And yet the battery is never flat, engine never fails to crank at start and never loses juice? Then it's charging correctly. Volt Ohm Meter (VOM/DMM) on the battery. Expect ~12.5 volts at rest with key on, ~13.5V while running. Curious: same or different alternator? |
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Posts in this topic
SKL1 Different voltmeter readings? Jul 14 2025, 08:44 PM
Spoke The dash voltmeter on my '71 reads between 12-... Jul 14 2025, 10:46 PM
GregAmy You should check the battery voltage with a DMM.
+... Jul 17 2025, 08:32 AM emerygt350 That dash volt meter is great for reminding you th... Jul 15 2025, 03:49 AM porschetub
That dash volt meter is great for reminding you t... Jul 15 2025, 05:18 PM SKL1 Good to know. Thx guys. Jul 15 2025, 07:25 PM barefoot I substituted the cigar lighter for a USB double p... Jul 16 2025, 02:45 PM 930cabman
I substituted the cigar lighter for a USB double ... Jul 17 2025, 05:53 AM emerygt350 Yes, but you really shouldn't even look at tha... Jul 17 2025, 11:36 AM SKL1 Both engines have their original alternators which... Jul 17 2025, 09:18 PM Spoke On my car I measured the battery voltage and recor... Jul 18 2025, 09:55 AM |
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