voltage issues

[AleroKing]

i have a aftermarket alternator and have had it for almost 2 years now.

Recently i have been having voltage drop in idle after my car is warmed up.

It will usually drop to around 13.8-14 volts at idle, and down to 13.5 with ac/ brights on. but when i get my rpms back up around 1000 it jumps up to around 14.8

It has a 15v regulator built in and has always stayed close to 15 volts.

[zzyzzx]

Those voltage levels are good. It drops when warmed up because it's done recharging the battery losses incurred during startup.

If you have a voltmeter mounted somewhere in your Alero, I'd like to know where (a pic would be great).

I occasionally use this voltmeter:
http://www.aleromod.com/forums/showthread.php?t=35034

But in my other car (not Alero) I mounted a standard 2" gauge in the dash.

[JLw7123]

Well how many batteries do you have and also have you done the big three upgrade with 0 gauge.

[AleroKing]

Those voltage levels are good. It drops when warmed up because it's done recharging the battery losses incurred during startup.

If you have a voltmeter mounted somewhere in your Alero, I'd like to know where (a pic would be great).

I occasionally use this voltmeter:
http://www.aleromod.com/forums/showthread.php?t=35034

But in my other car (not Alero) I mounted a standard 2" gauge in the dash.

I have a stinger volt meter in the pocket of my spare din.

But like I said it hasnt done this for the almost 2 years ive had it.

And it was a 15volt internal regulator , not low 14s like stock so the voltage should be higher.

The alternator does 160amps at idle 240 at 1000 rpm, so it shouldnt drop because of a load.

And i have 4 batteries load tested them all and checked all my power and ground conneCtions. The big 3 is also done with 0 guage and two 0 guage runs off the alt.

[a.graham52]

i agree that those voltages are well within specs. maybe not what they were when new? but if your vehicle went to a garage they would tell you there was nothign wrong. loosing .8v really isnt that big of a deal. if it went and stayed lower thne 13.5 i would be more concerned.

what you need to do is see how much amperage yoru alternator is putting out. voltage really isnt going to tell you a damn in this case.

[JLw7123]

He has a huge sound system. Most people with systems as big as his like to see the voltage stay above 14 volts.

[AleroKing]

i agree that those voltages are well within specs. maybe not what they were when new? but if your vehicle went to a garage they would tell you there was nothign wrong. loosing .8v really isnt that big of a deal. if it went and stayed lower thne 13.5 i would be more concerned.

what you need to do is see how much amperage yoru alternator is putting out. voltage really isnt going to tell you a damn in this case.

these voltages are within the specs of a stock alternator possibly that has a 14.4 regulator but mine has a 15volt one so it should be .6 higher and shouldnt drop at all because of a small load like ac

and there has been times with a heavy load at idle it will drop to about 13.2 which is what my batteries resting voltage is.

[AleroKing]

Just tried the stock alt and it was much worse dropped to mid 12s.

My idle is about 600 tops is this normal?

Please someone chime in this is very annoying

[zzyzzx]

Just tried the stock alt and it was much worse dropped to mid 12s.

My idle is about 600 tops is this normal?

Please someone chime in this is very annoying


At 600RPM you aren't going to get full voltage from any alternator. That's why taxi's sometimes have special or two alternators (something like that). What's the voltage at 1000RPM?

[AleroKing]

At 600RPM you aren't going to get full voltage from any alternator. That's why taxi's sometimes have special or two alternators (something like that). What's the voltage at 1000RPM?

Its a 250 amp alternator it used to put out full voltage at idle , it puts out full voltage at 1000 rpm

[a.graham52]

i still say your voltage is not an indication of what your alternator is puting out. its a 250A alternator... what is it putting out for amps?

[AleroKing]

i still say your voltage is not an indication of what your alternator is puting out. its a 250A alternator... what is it putting out for amps?

I had it tested at 160a at Idle 250 at 1000 rpm, but like I said I put the stock back on and the problem was worse.

Its a automatic 2.4 whats the normal idle on this engine?

[zzyzzx]

I had it tested at 160a at Idle 250 at 1000 rpm, but like I said I put the stock back on and the problem was worse.

Its a automatic 2.4 whats the normal idle on this engine?

I have the V6, but 600RPM sounds about right for a warmed up idle speed.

[falloutboy]

ever considered corrosion on the terminals plus side and ground side?
with these amps you want to make sure that every ground is in tip top shape (and not just the grounds you added or use)

ever measured if there is a considerable voltage drop in one of the connections (+ and ground)?

[AleroKing]

ever considered corrosion on the terminals plus side and ground side?
with these amps you want to make sure that every ground is in tip top shape (and not just the grounds you added or use)

ever measured if there is a considerable voltage drop in one of the connections (+ and ground)?

Yes all connections have been double checked and this is voltage at the alternator witg no music on.

[AleroKing]

I have the V6, but 600RPM sounds about right for a warmed up idle speed.

My friend has a 2.4 just sent me a pic of his tach was just under 750 and mines just above 500... Could I have a shop raise the idle it only seems to drop voltage under where his idles at.

[zzyzzx]

My friend has a 2.4 just sent me a pic of his tach was just under 750 and mines just above 500... Could I have a shop raise the idle it only seems to drop voltage under where his idles at.

That could be the real problem right there - low idle 600RPM is what I would consider at the low end of normal and your voltage will go up if you can slightly raise the idle. Not sure how to do that on this car, it usually does that all by itself as leaks develop, etc. when the car gets old.

[AleroKing]

The iac is bad

[zzyzzx]

The iac is bad

OK, so you put in a new one and what's the idle voltage and RPM now?

How many miles are on the car?

Last IAC I replaced was on a car that had over 150,000 miles on it, and after I replaced it, it was obvious that I was WAY overdue.