Need Voltmeter Advice - The 1947 - Present Chevrolet & GMC Truck Message Board Network

phanatic32212 · 05-12-2005, 12:37 PM

I just got a new Autometer voltmeter 8-18 volts. When I turn the ignition it reads 12V like it's supposed to, but when rev the engine it jumps up to 18V even with the headlights on. I know that it is supposed to go up under load, but that high? Also, will this do any damage to gauge, being pegged out for a decebt period of time?

TIA
phanatic

Old Dave · 05-12-2005, 12:47 PM

If I were you I would take a Digital Multimeter and check the voltage at the battery when it's running. It sounds like your regulator isn't regulating, since the new voltmeter reads 18V. Good way to fry some things quickly. Voltage should not go above 14.8V if it's working correctly.

Fred T · 05-12-2005, 12:50 PM

I'd check with a regular volt-ohm-meter. Your voltage reading should be 14.3 to 14.8. 18 volts will boil you battery to a premature, explosive death.

jhow66 · 05-12-2005, 12:55 PM

I'd say your gauge is off(like my autogauge from autometer). If it was putting out that much you would see a big rise in headlight brightness.

phanatic32212 · 05-12-2005, 01:19 PM

O.k. I checked the battery off:12.2V idle:14.4V then watch meter as i rev the engine and it goes up to about 15.5. the guage is right on at OFF, at idle the guage says a little more than 15V and under load the guage pegs out at past 18V. Should I call JEGS and get a new guage or is it something else. I thought Autometer's guages were calibrated and good to go out of the box.

Putter · 05-12-2005, 02:29 PM

Just out of curiosity...where did you make the connection for the volt gauge? To an ignition wire under the dash, under the hood, etc...????
You might want to take the alternator to the local parts house and have it tested....it's free to do...that way you will be 100% sure that is not the issue before you give Jeg's an ear-full.

Ackattack · 05-12-2005, 02:29 PM

I think the gage is fine.
I think your alternator is probably putting out 18V or more. Taking a reading across the battery is not a correct indicator (internal resistance) Measure the output of the alternator and compare to the gage.

**VetteVet** · 05-12-2005, 04:16 PM

Have you been having problems with your vehicle. Why don't you test another vehicle with your voltmeter and see if it does the same thing or if it reads ok. If it reads ok on another vehicle then your regulator is bad as the others have said. Do you have an internal or external regulator?

phanatic32212 · 05-13-2005, 02:00 PM

I want to thank all of you guys for keeping me from looking like a jackass. I was going to call JEGS and raise hell about this meter. Instead, I went to PepBoys and bought a voltage regulator for less than $30 and sure enough, 14.4V. You guys are geniuses!!! Thanks a bunch. I'll be back and hopefully I can give some info next time.

05-12-2005, 12:37 PM	#1
phanatic32212 It's Done When It Runs!! Join Date: Sep 2002 Location: Jacksonville, FL (Orange Park) Posts: 220	Need Voltmeter Advice I just got a new Autometer voltmeter 8-18 volts. When I turn the ignition it reads 12V like it's supposed to, but when rev the engine it jumps up to 18V even with the headlights on. I know that it is supposed to go up under load, but that high? Also, will this do any damage to gauge, being pegged out for a decebt period of time? TIA phanatic __________________ Or Give Me DEATH

05-12-2005, 12:47 PM	#2
Old Dave Is a bullfrog waterproof? Join Date: Nov 2000 Location: OLATHE, KANSAS Posts: 1,130	If I were you I would take a Digital Multimeter and check the voltage at the battery when it's running. It sounds like your regulator isn't regulating, since the new voltmeter reads 18V. Good way to fry some things quickly. Voltage should not go above 14.8V if it's working correctly. __________________ "It is better to remain silent and be thought a fool, than to open one's mouth and remove all doubt." Ben Franklin __________________ 1970 Chevy shortbed 2002 Harley Custom Chopper (Long sucker) 1998 K2500 5.7L 5-speed Longbed 1st two are My son's toys...they just live in my garage! 1997 GMC K1500 Suburban 1993 S-10 Blazer 4D (youngest son's daily driver) 2000 Dodge Ram 4WD Ext. Cab (5.9L) Wife is a late year 1951

05-12-2005, 12:50 PM	#3
Fred T Cantankerous Geezer Join Date: Aug 2002 Location: Bel Aire, KS Posts: 6,264	I'd check with a regular volt-ohm-meter. Your voltage reading should be 14.3 to 14.8. 18 volts will boil you battery to a premature, explosive death. __________________ Fred There is no such thing as too much cam...just not enough engine.

05-12-2005, 12:55 PM	#4
jhow66 Registered User Join Date: Jun 2002 Location: Knoxville Tenn. Posts: 3,058	I'd say your gauge is off(like my autogauge from autometer). If it was putting out that much you would see a big rise in headlight brightness. __________________ 56 Chevy Bel-Air 2dr. HT (purchased new) 71 Chevy Cheyenne SWB PU (502HO) 65 GMC short bed step--work in progress and my gofer

05-12-2005, 01:19 PM	#5
phanatic32212 It's Done When It Runs!! Join Date: Sep 2002 Location: Jacksonville, FL (Orange Park) Posts: 220	O.k. I checked the battery off:12.2V idle:14.4V then watch meter as i rev the engine and it goes up to about 15.5. the guage is right on at OFF, at idle the guage says a little more than 15V and under load the guage pegs out at past 18V. Should I call JEGS and get a new guage or is it something else. I thought Autometer's guages were calibrated and good to go out of the box. __________________ Or Give Me DEATH Last edited by phanatic32212; 05-12-2005 at 01:20 PM.

05-12-2005, 02:29 PM	#6
Putter More Cowbell.... Join Date: Mar 2004 Location: Puckett, MS Posts: 3,569	Just out of curiosity...where did you make the connection for the volt gauge? To an ignition wire under the dash, under the hood, etc...???? You might want to take the alternator to the local parts house and have it tested....it's free to do...that way you will be 100% sure that is not the issue before you give Jeg's an ear-full. __________________ *There once was a member from Puckett.....Who ( fill in the blank blank blank* ) bucket**

05-12-2005, 02:29 PM	#7
Ackattack Senior Member Join Date: Aug 2002 Location: Valley Center KS Posts: 3,525	I think the gage is fine. I think your alternator is probably putting out 18V or more. Taking a reading across the battery is not a correct indicator (internal resistance) Measure the output of the alternator and compare to the gage. __________________ Project Bruiser: 68 Pro-Touring C-10 5.3L / 4L60E Project Ironhide: 97 GMC Crew Cab 4x4 Cummins SOLD: '69 GMC 1/2T SWB TBI'd: Project No Buck Assembly Manual Index Sign up Thread!!! Factory Service Manual Index

05-12-2005, 04:16 PM	#8
VetteVet Msgt USAF Ret Join Date: Jan 2005 Location: Kalamazoo, Michigan Posts: 8,717	Have you been having problems with your vehicle. Why don't you test another vehicle with your voltmeter and see if it does the same thing or if it reads ok. If it reads ok on another vehicle then your regulator is bad as the others have said. Do you have an internal or external regulator? __________________ VetteVet metallic green 67 stepside 74 corvette convertible 1965 Harley sportster 1995 Harley wide glide Growing old is hell, but it beats the alternative.

05-13-2005, 02:00 PM	#9
phanatic32212 It's Done When It Runs!! Join Date: Sep 2002 Location: Jacksonville, FL (Orange Park) Posts: 220	I want to thank all of you guys for keeping me from looking like a jackass. I was going to call JEGS and raise hell about this meter. Instead, I went to PepBoys and bought a voltage regulator for less than $30 and sure enough, 14.4V. You guys are geniuses!!! Thanks a bunch. I'll be back and hopefully I can give some info next time. __________________ Or Give Me DEATH



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