Idling voltage/charging help, please

So, 1899 has a new Yellowtop battery, NSA alternator, and new alt belt. I was having problems figuring out where all wire connections went, but I finally figured out. However, now there is an issue with the idle voltage. It looks like the battery is charging, but not all that well.

Before turning the car on, the battery read 11.7v. After it was turned on, it initially read 14.3v during idle, but slowly dropped over time. During a test of a constant 2000rpms, the reading went back up to 14.1v. After taking my foot off the gas pedal and letting the car idle, it dropped once more to 13.4v.

The car had not been run in several months, and it was not driven around to check the voltage after this, as I had the front driver wheel still off from replacing the alt belt. Since the car had been sitting for so long, and the voltage has not yet been tested after being driven, I am not sure if the system is behaving as it should be, or if something is wrong. I had heard the system, during idle, was supposed to read a constant 14.2-14.3 voltage.

Thanks for the help.

 

[1990ggsxnj]

Ideally any system SHOULD be charging around 14v all the time, but all 3 of my galants are at a constant 13.1-13.4v at idle. I also noticed the 11.7V before turning the car on. Usually this is 12.1-12.3 for me as this is the battery voltage, but does any one else drop below this as well?

 

[toybreaker]

This thread has some good information on how to troubleshoot your issues.

 

[turbowop]

Both my gvr4's idle with voltage in the 13's. When first starting the cars they idle with 14.2 or so, but then drop to the 13's as the car warms up. At night with lights and accessories on it gets a little worse. I usually get a higher reading if I use a multimeter right off the battery rather than going off of my logger. Haven't had any issues with them due to the voltage being below 14 volts.

 

[BluFalcon]

I had the same situation with idle voltage in my car for awhile after I first got it. Voltage @ idle as displayed on my Apex-i TT was always in the 13.4V range, going up to 14V as RPM increased or while @ cruise. I added a fuel pump rewire kit from FP to the car, and cleaned a few of the grounds and the battery terminals while I was installing the kit. I was happy to see that voltage @ idle was now 14.1V constant. Haven't seen it drop voltage @ idle since, except for when the belt slipped a bit after driving through some standing water in a thunderstorm. I use a smaller Odyssey battery, so I'm always watching the voltage. Check your grounds and clean your terminals. Couldn't hurt.

 

Yes, I called the dealership and they verified the numbers as accurate. Let the record show that for future inquirers.

Unfortunately, the charging system is no longer working for me, AGAIN. I am going to try to tighten the belt again, we'll see where that gets me. It is also possible that while filling up the power steering resevoir, I got some on the belt. However, after inspection, there didn't appear to be any wetness on the belt or the alternator itself. Lastly, I am worried about the state of the alternator. For whatever reason, I forgot to disconnect the battery while working on the alt, a comically stupid mistake in itself, and when I touched the bolt sticking out of the alt (vocab escapes me, but the bolt/screw sticking out where two of the wires are fastened to with a nut,) sparks flew. Electronics aren't my strong suit, and I am wondering if that damaged the alternator.

Regardless, when the car is idling the battery reads 11.5v at the moment, and there is no change to this when RPMs are increased all the way up to 6000. Advice and/or thoughts would be great. Thanks guys.

 

[toybreaker]

Quote:

Regardless, when the car is idling the battery reads 11.5v at the moment, and there is no change to this when RPMs are increased all the way up to 6000. Advice and/or thoughts would be great. Thanks guys.



Check the voltage at the back of the alternator on the ring terminal.

 

Sorry, I gotta ask....how do I do this? Red lead on the voltmeter touching the ring terminal, black lead grounded on the chassis/body.

 

[toybreaker]

^^^ That's it, exactly! /ubbthreads/images/graemlins/smile.gif

This will verify one of the alternator fuses isn't popped.

It will also check the voltage drop in the wiring over to the battery/fuse box. There may also be something wanky at the terminals/connections, and this test will show what the alternator is doing.

 

I'm assuming I want the car turned off while doing this, correct? Or do I want it running? lastly, what readings am I looking for?

 

Well, I did the test. Not 100% sure I did it correctly, but I believe that I did. Regardless, voltmeter read 0.0v. Paid good money for this alt and now it appears to be dead. Yay. I have a feeling the 2 year warranty doesn't cover this. Anyway, I'll be taking it out soon and bringing it to a shop to have them test it as well, just to be sure. Oy.

 

[toybreaker]

if you got nada at the alternators ring terminal, you gots a fuse popped, or a wiring issue.

Replacing the alternator will not fix your issue.

 

Good to know.

Well, what is the next step?

 

[toybreaker]

Dude, have mercy... /ubbthreads/images/graemlins/rofl.gif

I'm posting from my phone, and it'll take till next tuesday to enter teh text, Capische?

That other thread had just about everything you need to know in it.

if you need moer than than was in that thread, I sent you a pm with my number, call me and I'll walk you thru it.

 

[turbowop]

Quoting turbowop:
Both my gvr4's idle with voltage in the 13's. When first starting the cars they idle with 14.2 or so, but then drop to the 13's as the car warms up. At night with lights and accessories on it gets a little worse. I usually get a higher reading if I use a multimeter right off the battery rather than going off of my logger. Haven't had any issues with them due to the voltage being below 14 volts.



Just as a data point I'd like to add to my above quote. I just got home from a 300 mile round trip journey to Seattle. I checked my logger and while driving down the freeway I was seeing 14.1 volts pretty much the whole trip. Bosch alternator, about four years old now, but only 10k miles or so. Checking my Apexi turbo timer showed .5 volt lower than the logger at all times. Interesting. /ubbthreads/images/graemlins/dunno.gif

 

[toybreaker]

Quoting turbowop:
Quote:



Both my gvr4's idle with voltage in the 13's. When first starting the cars they idle with 14.2 or so, but then drop to the 13's as the car warms up. At night with lights and accessories on it gets a little worse. I usually get a higher reading if I use a multimeter right off the battery rather than going off of my logger. Haven't had any issues with them due to the voltage being below 14 volts.



Just as a data point I'd like to add to my above quote. I just got home from a 300 mile round trip journey to Seattle. I checked my logger and while driving down the freeway I was seeing 14.1 volts pretty much the whole trip. Bosch alternator, about four years old now, but only 10k miles or so. Checking my Apexi turbo timer showed .5 volt lower than the logger at all times. Interesting.




Mark, that's a good observation.

I remember seeing that on a few other cars as well.

I don't have my diagram in front of me, but I think it's because the ecu recieves power straight from the mpi relay which is fed straight from the battery, so it's only got some low resistance points to go thru. The logger will read the supply voltage at the ecu.

The turbo timers usually pull their power from the ignition switch with a "t-harness". many of the turbo timers will use the switched side of the key for their voltage reference, so there can be as much as a half volt drop accross the igntion swicth from all the other items on that circuit, as well as the resistance of the igntion switch itself.

 

[turbowop]

That's good to know. It's annoying to keep the turbo timer on the voltmeter parameter at night because it starts flashing when the voltage it reads drops below 12.x volts. It starts flashing at night constantly since the lights are on as well as any other accessories, so I usually keep it on a different parameter. I hate seeing warning flashes going off, even if they're incorrect. /ubbthreads/images/graemlins/uhh.gif

 

[iceman69510]

Quoting Silvertooth:
Well, I did the test. Not 100% sure I did it correctly, but I believe that I did. Regardless, voltmeter read 0.0v. Paid good money for this alt and now it appears to be dead. Yay. I have a feeling the 2 year warranty doesn't cover this. Anyway, I'll be taking it out soon and bringing it to a shop to have them test it as well, just to be sure. Oy.



As you asked above, you need to do this running. If you did it turned off, you only get battery voltage, and not any diagnosis of the alternator.

 

Thanks. I should have specified that I DID do it with the car running. The reason why I was wondering if I did it correctly or not is because I touched the negative lead to the painted chassis and then next a semi-rusted but un-painted bolt. The former could have an effect on the reading, but I don't think the latter would. Both read 0.0v with the engine running. so, now I am going through that thread toy posted trying to figure out what to do next.

Toy: I might call you later, but today is complicated, as we're having my little cousin's graduation party at our house and I'll be busy with that most of the time.

Anyway, off to take a few minutes to try and troubleshoot this...

 

Looks like the 100A ALT ALT fuse in the "Fusible Link / Raccord Fusible" box right off of the positive battery terminal is broken. Whether or not it's the only problem, it needs to be replaced. Are these kinds of fuses easy to come by? I've never seen a fuse like that before.