Amp gauge working overtime

leo1287 · Post by **leo1287** » Sun Dec 05, 2004 10:07 pm

Hey Jeffc,
I installed the upgrades you recommended, electronic voltage regulator and ballast resistor from Summit Racing. Had already put in the Pertronix point replacement kit and coil. Noticed today the amp gauge is running high and amount depends on rpm.
Did I do something wrong? Only seems to be able to hook up the voltage regulator one way. Ballast hooked up like the old one.
What is happening?
Thanks, Dwayne

Jeffc · Post by **Jeffc** » Mon Dec 06, 2004 12:26 am

There really is no way to mess up how the alt is pugged into the
regulator since this is one field wire system, so if you are over charging it has to elsewere.
But let's take this a step at a time.

This regualtor puts out a constent voltage of 13.5 no mater if it is
pulling from the alt or the battery (unless the battery has less).
They work a little differant than your old point type regulator
and respond faster to loads.

A weak battery with sometimes cause the regualtor to charge to
much (ie. shorted plates in battery or crud build up because of age)

If your battery was a little low, it might do that till fully charged and rate of
charge will change with rpms. It could be that your old regulator was
not working up to spec. and now your getting a full charging. It could
be also that your alt is one of the older type that only puts out
35 to 45 amps, if this is the case it will take longer to charge the system
than a 65 to 70 amp unit.

I would go to all the grounding points on the engine also, battery to
engine, engine to fire wall and make sure your cables are in good
shape and points of contact are clean (including battery posts
and the large power cable from alt to fire wall and all points on the
start relay on drivers fender ).

Unless your alt gauge is WAY over (or pegged) to the right at higher
rpm and/or you smell burning or see melting
wires you should be just fine. If you are really worried, take and
have the system tested at a auto parts store (they will do it for
free in hopes of selling something).

The needle on the guage should mostly be to the charge side (+)a little
when the engine is running and battery is fully charged
and will drop at low rpms to the neg ( -) side, how far will depend on load the system is under (ie.what is on, lights, heater, wipers, ect) and when rpms incress the needle will swing over to the (+) side to make up what was pulled from the battery at low rpm, how far and how long will depend on what was used and once the battery is fully charged it will stay just to the right of center. You may notice that even using turn signals will give a the alt gauge a little movement.

leo1287 · Post by **leo1287** » Mon Dec 06, 2004 8:56 pm

Thanks Jeff,
The truck does not get driven much as yet, making lots of changes. Don't smell anything indicating hot wires, but amp gauge is plus side. Could be like you say and old reg was not up to snuff. Still have the original alternator, is there any way to tell what model it is? Also do not know how old the battery is. I'll keep an eye on it.
Again thanks,
Dwayne

Jeffc · Post by **Jeffc** » Mon Dec 06, 2004 9:52 pm

Kind of hard to tell on some, if it has large square holes in the
back its a late model and should be between 65 to 75 amp.
If no square holes it may, or may not, be the higher amp model,
a lot will depend on when it was replaced last. About all
that has been offered for rebuilds in the last 20 years is a higher amp model.
If it's the stock one that came on the truck it will be the lower amp model for sure.

Jeffc · Post by **Jeffc** » Mon Dec 06, 2004 10:06 pm

Kind of hard to tell on some, if it has large square holes in the
back its a late model and should be between 65 to 75 amp.
If no square holes it may, or may not, be the higher amp model,
a lot will depend on when it was replaced last. About all
that has been offered for rebuilds in the last 20 years is a higher amp model.
If it's the stock one that came on the truck it will be the lower amp model for sure.

JJ · Post by JJ » Wed Dec 08, 2004 11:29 am

Jeff may have mentioned this and I missed it but if that field wire is grounded anywhere it will peg that amp gauge at any thing above an idle. You didn't say how far it was into the red.

leo1287 · Post by **leo1287** » Wed Dec 08, 2004 9:21 pm

At idle the gauge is 1/2 way and by 2000 rpm it is pegged. Have not had time to check and clean connections yet, try to in the next couple of days.
Thanks guys,
Dwayne

Website · Post by **wideblock** » Thu Dec 09, 2004 12:04 am

take a volt meter and chack at the bettery what the charge rate is at idle and at 2000rpm. should never go above 14.5 or drop below 12. if it does, either your alt or volt reg aint working right. if its in the scale, id say your battery is toast or you got a bad lead to the battery causeing too much draw.

Jeffc · Post by **Jeffc** » Thu Dec 09, 2004 12:06 am

Good point JJ, if it is the stock wire it may have gotten cracked
somewere over the years, or otherwise weak.
pegged at 2k is not good, plug old regulator back in and see if it
still does it. If it does then it has to be some were else in the system.
Be sure that your ground wire between engine and fire wall is
good.

leo1287 · Post by **leo1287** » Fri Dec 17, 2004 9:00 pm

Hello all,
I finally got around to checking and replacing the block to firewall ground cable. The old one was missing much covering and had lots of elec tape.
Pulled the new voltage regulator and scraped off paint on the firewall and mounted the strap between the firewall and the regulator to make good grounding. Started the truck and same thing, looked away and the needle came back to center and stayed there. Might be fixed. One day when I have more time I will remove all grounding wires and clean them.
Dwayne

Website · Post by **wideblock** » Fri Dec 17, 2004 11:52 pm

man, grounding on these old trucks can run to to insanity. best to do them all at once, seems to clear up a ,lot of mysterious problems and gremlins

Jeffc · Post by **Jeffc** » Sat Dec 18, 2004 2:52 am

Boy, Trey you can say that again and again and again ........

Without good grounding back to the battery, the system
just does not very well and will cause all kinds of
little and big problems. As in all electrical systems you need
to make a loop of some kind, weak links in that loop
will show up in strange way sometimes.