1styota4X4

I have searched but have a weird question and was wondering if anybody else had this issue....

I have a 1995 4 runner 3.0 5 speed...i have been running a volt meter for the past 4-5 days and the volts range from 13.5 all the way down to 10.5 and it cycles seems like the average is around 12.2-11.8 do you think this could be a loose or worn connection or like i think just a bad altenator i figured i would ask before i shell out 85 buck for a new reman...

thanks

mastacox

Did you calibrate the volt meter? CAN it be calibrated?

1styota4X4

no it cant be calibrated but all i was looking at the was the volts and it was falling in line with the volt gauge on the dash

1styota4X4

any other input on this before i shell out some money on a reman alt

mastacox

I would check the voltage on your battery's poles with the engine on and off first, using a digital voltage gauge from Radio Shack or something. My guess, you're fine and the gauge is off.

midiwall

Umm... I gotta counter here Brian...


If your meter is tracking the slumps with the dash meter, then I'd say that your VOM/DMM is fine. It would be WAY rare these days for a VOM/DMM to be out of whack. Even a cheap $15 meter will be accurate enough for this.

Yes, it could be just a connection, but my gut feel would be alternator. Test the voltage right at the battery terminals and see if you get the same symptom. Test with and without the engine running, then with and without the battery connected.

Let us know what you see as to swings and we'll take it from there!

TNRabbit

Check out these replacement alternators; they are awesome! They have a GM 200 amp that will fit your Yota: http://www.alternatorparts.com/Extre...144%20type.htm

midiwall

Ummm, nice stuff, and actually I'm about to order a 140 from those guys, but...

..given that 1styota4X4 is thinking about dropping $85 on a remanufactured replacement, I think that suggesting spending $370 on a 200 amp alternator is a bit out of scope.

1styota4X4

i am using a fluke volt meter on the bat terminals and it cycles anywhere from 11.5-13.5 with it running the battery is a new optima red top that replaced the old one b/c when tested it was bad(1 year old)....it seems to charge better after i just start the car(after it sits for a while) and after i drive for a little while it seems to cycle between 11-13 (10.4 volts is the lowest i have seen and 13.8 volts is the highest) it really weird i disconnected my amp for my sub a week ago and no change in symtoms is there something else i could be missing...my gut tells me altenator to but sometimes it wont drop and just set at 13 volts with the ac running...


i would love to do a bigger alternator but if my plans work it wouldnt fit on the 4.3 vvti i am trying to get my hands on to put in my truck(but that proect is still 12 months off)

midiwall

Wow... umm, some punctuation would help.

Lets see... so,

• New optima red top
• Engine running, voltage cycles from 11.5-13.5
• After driving, voltage cycling shifts to 11-13
• Pulled the sub amp, no change
• Constant 13 volts with A/C running

It actually sounds like a regulator. If it was the alternator you wouldn't be seeing the 13.5v to start with. But, the regulator may not be separately replaceable, so you might be stuck with swapping the whole thing.

midiwall

ummm... there's the text "Electric Fan" in your sig. Any chance that the voltage cycling is in time with _anything_, most notably the fans?

1styota4X4

no when i run the a/c both fans kick on and stay on

mastacox

The electric fan could very possibly be giving you problems...

Does the voltage vary with rpms, or does it just randomly move around? What does the voltage say when your key is "on" but the engine is off, as in the battery by itself? If your battery really is at 11V, your starts should be really slow, almost like it won't make it...

If your car starts normally, however, the voltage on the battery is probably 12.0-12.4V, which would mean the gauge is off. Most gauges have a built-in way to adjust them because you will get a voltage drop accross the wires going to the battery and it has to be accounted for. I have a Stinger digital voltage gauge (which had to be calibrated by the way), my voltage goes as high as 14.7 when I first start my engine, and usually settles down to 14.0V for rpms over 750, but may drop to about 13.0 if I'm idiling at about 500rpms without A/C and my e-fan is running. Your range of voltages is about the same delta, there is just a built-in bias somewhere.

Here's a good question: what did your gauge read when you first installed the new Optima? Did it read 12 or more by itself, or did it say 11? Also, does your voltage vary when the e-fan turns on? It is possible if you have a stock alternator that it cannot keep up...

mastacox

Optima's have a 3-year warrantee, you should have been able to get it replaced for free...

1styota4X4

yea the battery was replaced for free the battery does sit at about 12.2 with the key on & fan off....

mastacox

Hmmm...

Well my guess is your stock alternator can't keep up with your electric fan. What kind of fan do you have?

1styota4X4

its the flex lite electric it was on the car when i bought it.....now it seems like every other day or so it dosent want to turn over to start it tries to then stops..when I try again it starts...i am about to start pulling my hair out...

mastacox

It sounds like your fan is overpowering your alternator and draining your battery. I would suggest upgrading to a high output alternator around 100 amps, such as an alternator out of an MR2 Spyder. Unfortunately you may end up needing a new battery also, unless its a deep cycle drained batteries will tend to die on you...

You should read this thread, I had similar problems when I first installed my electric fan on my car:

Electric Fan Thread

1styota4X4

i will have to check the load across the fan(will try and do it in a day or so) the previous owner put it in with the new motor 30K ago it was his wifes car so he was very metacilious(sp) with the car....the car does not start to over heat unless i am crusing at 75-80 MPH for a sustained amt of time thanks for all the insight i will up dat this soon when i find a solution

mastacox

Well overheating is an entirely different issue, lets cover the electrical first...