Anyone having voltage issues?

Almighty-Si · Post by **Almighty-Si** » Sat Mar 06, 2010 10:41 pm

Took the car on a nice long ride today and while I got stuck in a little traffic I noticed my battery voltage datalogging was going from 12.16 volts or so up to 14+volts as I started moving again. Thing is, I never had a problem with the charging system. Also, looking through a friends datalogs the other day trying to help him out I noticed that his car was doing that exact same thing. Has anyone else noticed anything like that in their datalogs? I mean I actually noticed it driving the car tonight as my dash lights dropped pretty low, until I got the car up around 3000rpm and the dash lights became really bright. My altenator has 28k on it and my battery is brand new. My friends car is the same, though his altenator is newer and his battery is also new. Wonder if there is something going on in eCtune to cause this cause this is the only thing that changes month to month.

Post by **Gaskleppie** » Sun Mar 07, 2010 4:27 pm

The voltage is always lower at idle so what is your point?

Almighty-Si · Post by **Almighty-Si** » Sun Mar 07, 2010 7:48 pm

I always got 14 volts at idle. Cruising at speed voltage will drop to low 12's and back up low 14's without changing engine speed. 2 different cars with good charging systems with the same problem, that's my point.

Bindegal · Post by **Bindegal** » Tue Mar 09, 2010 5:40 pm

Theories... 1)Maybe that charging system isnÂ´t working so well after all? 2)Voltage shown in eCtune is what the ECU sees. So any bad connections or voltage drops would show up. Could be some bad wiring/ground connections or perhaps someone connected a wideband and other stuff draining current to the ECU loom? /Allan

JaredKaragen · Post by **JaredKaragen** » Tue Mar 09, 2010 11:45 pm

You should run an inductive diode check on your charging system... It could cause your regulator to go out... But.... When this was happening to me the first time, it ended up being a rusted connector where the wire connects at the alternator. I changed out the wire, problem went away... Btw: dealing with this issue... I almost lost a pinky reaching down there.... Timing belt took it all te away around the cam.

I would test your charging system first... If u can take the alternator out there are tests in the oem manual, or take it to a parts store with a tester.

danz · Post by **danz** » Mon Mar 29, 2010 12:28 pm

JaredKaragen wrote: Btw: dealing with this issue... I almost lost a pinky reaching down there.... Timing belt took it all te away around the cam.

yet another reason to use a timing belt over a timing chain. hehe

Almighty-Si · Post by **Almighty-Si** » Tue Mar 30, 2010 12:37 pm

I haven't done anything to any wiring since my turbo install about 7 years ago. All my connections are soldered and covered with heat shrink tubing. Never had any issue like this until just recently. The car is a 99 but it only has 28,000 miles on it. I can pull the altenator and have it checked but I can't see it failing so quickly. I just found it funny that I was trying to help a friend out with his car and noticed his voltage dropping and raising and then go out in my car and notice the exact same issue on my car. His car also has a new altenator (about a year old) and a new battery as well. Honestly the only that changes on my car month to month is the program after updates. As of late, since the update to ROM .65 my car has been the worst it's ever been.

Bindegal · Post by **Bindegal** » Tue Mar 30, 2010 1:05 pm

Did you actually check the voltage at the ECU with a voltmeter or are you just assuming the software would somehow read the wrong voltage at idle? For whatever reason, lots of people usually start looking for complicated answers to simple mechanical/electrical problems..... /Allan

Almighty-Si · Post by **Almighty-Si** » Tue Mar 30, 2010 3:07 pm

Cause lord knows it could never be a software issue Hey maybe datalogging not being able to record any boost issue is a mechanical problem as well. I am pulling out the altenator later and will have it and the battery tested tomorrow. I will make sure all the connections are good and clean as well. I almost can't wait to hear what you'll say when everything comes back checking out fine (which i'm sure it will).

Bindegal · Post by **Bindegal** » Tue Mar 30, 2010 3:37 pm

Why oh why would you pull out parts to have them individually tested before getting the multimeter out and making simple diagnostics on the car itself? WeÂ´re talking basic automotive troubleshooting which could be done in somewhere between 5 and 15 minutes, tops. Even if it really does turn out to be a software issue, your diagnostics method seems illogical.

/Allan

Almighty-Si · Post by **Almighty-Si** » Tue Mar 30, 2010 5:00 pm

Use a multimeter pull the altenator you guys need to make up your minds. To make you happy, before I pull everything out I will put a multimeter on it and check it. Going out to do it right now.

JaredKaragen · Post by **JaredKaragen** » Tue Mar 30, 2010 5:56 pm

A diode/rectifier check can be done with the car running, snapon makes a nice unit for that... I would guess alternator is going out; but my problem mentioned above was the oem harness wire for the alternator output... So it can happen to anyone.

Almighty-Si · Post by **Almighty-Si** » Wed Mar 31, 2010 1:05 am

Ok checked it with a multimeter started the car up and let it run about 20 minutes voltage at the ecu 14.2 - 13.9 the whole time. Pulled the altenator and battery out and will be having them check tomorrow. I inspected the harness for loose wires at the altenator and nothing loose there. Also inspected the large white wire at the top sitting correctly and tight, clear of any debris or corrosion and still solid connection to the wire itself. Also to clear up another arguement just in case it should araise, I checked all my grounds and power connections and they are fine as well. So I guess we will see what the altenator and battery test says tomorrow.

Almighty-Si · Post by **Almighty-Si** » Wed Mar 31, 2010 1:39 pm

Well as I suspected, according to autozone...battery and altenator check out just fine.

JaredKaragen · Post by **JaredKaragen** » Thu Apr 01, 2010 10:14 pm

I'm pretty sure it's the voltage regulator.... Their test doesn't include engine temps. The reg kicks on and off charging the battery as needed.... Tis why battery offsets are necessary.... I have had 3 hondas that have done this. Try checking with a multimeter when the issue is being logged to confirm, but it's definately not the rom causing this... I don't see how. Worst case turn off alternator control and call it a day.