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Need suggestions - my amp gauge is acting like a tach #1275693
07/29/12 12:33 PM
07/29/12 12:33 PM
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Virginia
RM21N0A Offline OP
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Drove my 70 RR around this morning, but noticed right away that the amp gauge is not right.

Here's a picture at idle:

Re: Need suggestions - my amp gauge is acting like a tach [Re: RM21N0A] #1275694
07/29/12 12:34 PM
07/29/12 12:34 PM
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Virginia
RM21N0A Offline OP
mopar
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And here is a picture at about 2,000 RPM:

Any ideas??

Re: Need suggestions - my amp gauge is acting like a tach [Re: RM21N0A] #1275695
07/29/12 12:37 PM
07/29/12 12:37 PM
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West Plains, MO
DrCharles Offline
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Quote:

And here is a picture at about 2,000 RPM:

Any ideas??




Your voltage regulator is fried (or maybe improperly grounded), so it's calling for full alternator output at all times. Don't drive the car (or rev it) until you get this fixed... will hurt your battery, bulbs, and possibly other electronics from overvoltage!

Re: Need suggestions - my amp gauge is acting like a tach [Re: RM21N0A] #1275696
07/29/12 12:39 PM
07/29/12 12:39 PM
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Lincoln Nebraska
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RapidRobert Offline
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Quote:

Any ideas??


Voltage regulator went bad. Dont run it till you fix it as that "full fielding" will fry wires/bulbs/wreak havoc on the electrical system. Do make sure the VR is adequately grounded


live every 24 hour block of time like it's your last day on earth
Re: Need suggestions - my amp gauge is acting like a tach [Re: RM21N0A] #1275697
07/29/12 01:03 PM
07/29/12 01:03 PM
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chicagoland,usa
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buildanother Offline
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Or your battery is low on charge.

Re: Need suggestions - my amp gauge is acting like a tach [Re: DrCharles] #1275698
07/29/12 01:41 PM
07/29/12 01:41 PM
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Virginia
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The VR still seems to be grounded OK, and I just bought it about 5 years ago, so I fooled around with the wires where they go into the bulkhead connector.

Thought I had it at first, because I started it up and the needle stayed between +10 and +20.

Then I poked around some more and closed the hood, started it up again, and the needle was pegging again.

Guess I'll go out and buy another VR and see what happens.....

Oh - also, I'll hook my battery charger and test the voltage/percentage level just in case that could be it, but I think the battery is good.

Re: Need suggestions - my amp gauge is acting like a tach [Re: RM21N0A] #1275699
07/30/12 07:39 AM
07/30/12 07:39 AM
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Washington
skrews Offline
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possible field wire grounded

Re: Need suggestions - my amp gauge is acting like a tach [Re: RM21N0A] #1275700
07/30/12 12:28 PM
07/30/12 12:28 PM
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RapidRobert Offline
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Quote:

Thought I had it at first, because I started it up and the needle stayed between +10 and +20.

Then I poked around some more and closed the hood, started it up again, and the needle was pegging again.


If you revved it & it didn't peg then it did that would point to a wiring/grounding problem elsewhere rather than the reg, as when a reg goes bad it stays bad. Holler how it turns out.


live every 24 hour block of time like it's your last day on earth
Re: Need suggestions - my amp gauge is acting like a tach [Re: RapidRobert] #1275701
07/30/12 12:45 PM
07/30/12 12:45 PM
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Nunya CA
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Why not just by pass it all together using the MAD Electric upgrade. I will never again rely on the original for electrical status. It is the weak link for sure. Just do it and then add a Voltage meter and all will be good....

Re: Need suggestions - my amp gauge is acting like a tach [Re: CR8CRSHR] #1275702
07/30/12 03:02 PM
07/30/12 03:02 PM
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Kansas
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Quote:

Why not just by pass it all together using the MAD Electric upgrade. I will never again rely on the original for electrical status. It is the weak link for sure. Just do it and then add a Voltage meter and all will be good....




Probably the best thing I ever did to my coronet. Especially when I later upgraded to a 318 magnum with serpentine setup... the alternator on that would have fried everything if I hadn't done that upgrade already

Re: Need suggestions - my amp gauge is acting like a tach [Re: RapidRobert] #1275703
07/31/12 08:02 AM
07/31/12 08:02 AM
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Virginia
RM21N0A Offline OP
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Virginia
The new VR (NAPA - Echlin brand - $29) came with a sheet that had this test:

Disconnect VR, connect jumper wire to FIELD side of harness that goes to the VR. Start car, watch amp gauge while grounding the jumper wire momentarily. Needle should jump to the right, if it does not, problem is somewhere in the wiring.

Needle moved to the right, so that was good.

Also, I checked and re-checked all the wiring, and could not see any problems anywhere.

Installed new VR, started car, revved engine, needle pegged to the right, then settled down to around +10 to +15 and stayed there, so I don't know, maybe it's OK now. But the needle used to just stay steady slightly to the right of zero.

One other possible clue I should have mentioned, when I start the car the temp gauge spikes to the right for a second, then goes back to normal. Has been doing that off and on for years, but does it more here lately.

I'll play with it some more this weekend and remove the instrument cluster to check the back, but still would like to hear any more ideas.


I also like the idea of the MAD conversion.
I looked into that a couple of years ago but didn't get around to buying the stuff and doing the install.
I'm exploring Mark's site (madelectrical.com) but cannot find exactly what I remember from when I read up on it before. Do you have a link?

I thought there was something in moparts Tech Archives about the MAD conversion but could not find it there either.

Thanks to everyone for all of the ideas so far.

Re: Need suggestions - my amp gauge is acting like a tach [Re: buildanother] #1275704
07/31/12 03:55 PM
07/31/12 03:55 PM
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northwest USA
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NANKET Offline
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Quote:

Or your battery is low on charge.




The voltage monitors system voltage. It recharges the battery and runs all the electrical components while the engine is running. First thing is to check you battery, how old is it, is it still good, meaning will it take a charge? Make sure it is charged, if you have been starting the engine many times the battery could be low, that is the biggest draw on a battery. Also check your battery cables, clean posts, ends, snug clean and dry connections on both ends of both cables. Then check out the bulkhead connector, same as battery connections. These things are important on all cars elec systems.

Re: Need suggestions - my amp gauge is acting like a tach [Re: NANKET] #1275705
07/31/12 04:36 PM
07/31/12 04:36 PM
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RapidRobert Offline
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I'd slow charge the batt overnight & see if the needle is slightly to the right like it was way back. If not I'd take off both field wires from the alt and the connector from the reg & with jumper wires with alligator clips on both ends jump 12V from the batt positive post to one of the alt male field terminals and to the reg "top blue wire" male terminal and jump from the other reg "side" male terminal to the other alt male field terminal & jump from the reg case to the batt neg post & see if you're good at a fast idle. If so that tells you the hard components (alt/reg/batt) are good & the problem is in the wiring/grounds. The Madd upgrade has it's good points but if the overcharging ain't dealt with 1st the overcharging will fry something in the system & you'll see 15-16 volts on a voltmeter as opposed to the ammeter pegging. What Nanket said, clean the connections especially the bulkhead & reg ground after you've verified the batt is topped off & see where you're at


live every 24 hour block of time like it's your last day on earth
Re: Need suggestions - my amp gauge is acting like a tach [Re: RapidRobert] #1275706
09/09/12 04:35 PM
09/09/12 04:35 PM
Joined: Jun 2005
Posts: 531
Virginia
RM21N0A Offline OP
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Virginia
Thanks RapidRobert and everyone else - I haven't had time to do everything suggested, but the problem seems to have gone away.

The battery is still real strong (only about 2 years old). I checked carefully for shorts and cleaned all of the connections when it first happened - battery, VR, bulkhead, etc., but I didn't think that solved the problem at first.

Since then though, with short test drives it has not acted up. So I took I just took a nice 60-mile cruise, and everything was great.

I'll be keeping an eye on it, and will keep you posted if it happens again.








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