You think I need a new alternator with these readings....

[jimdigs]

Without a load the multimeter reads 13.8 with a load, lights, radio, wiper, heater, 13.5. If I do need an alternator, where do you guys buy yours from? I checked rock auto and they are the cheapest but how do you do the core exchange? Seems like more of a pain if I have to ship the core in. Is there a certain brand you prefer? Thanks

Oh, forgot to add, brand new battery.

[blake4591]

The rockauto core exchange is actually really easy. They give you an option to print a prepaid shipping label that will be taken out of the core fee when they refund it. It is also usually cheaper since it ships against their commercial account at a better rate. You just print the label put the core in it's original box, put that box in a bigger box, tape the shipping label to the outside box and drop it off at Fedex.

[firebush357]

13.8 Volts sounds good to me.

[gergorian]

13.8 Volts sounds good to me.

Agreed. 13.8 sounds "maybe" a tad low but well within the acceptable range.

[ryanprins13]

What problems were you having that made you test it?

Sent from my SM-G920W8 using Tapatalk

[FestYboy]

The alt is ok. A tad low, but ok. 13.4 with a load is the lowest you want to see to keep things happy.

[jimdigs]

Okay, what the problem is is that the car is cranking over slow and barely starts. Last night at work it took forever for it to finally start and it was really turning over slow. I just bought the battery, cheap Walmart one, back in Oct. I think it was, is it possible that even though the multimeter shows it fine that something could be wrong with it? According to the multimeter both the alternator and battery are good. What else is there to check for?

[FestYboy]

Define "good".

Any corrosion at any contact point within that circuit can cause a slow crank. Anything above 1/2 ohm can cause a no crank situation.
Do this: borrow a friend, have them crank the engine while you have your multi meter touching the positive post and the main power wire at the starter. The voltage drop shown should be under .5 volts. Then have friend crank again with the multi meter on the positive and negative terminals on the battery. The voltage shouldn't dip below 10.5

You can also can do a voltage drops between the battery post and the terminal... A clean contact will show a very low number.

Please note: there is a difference between a battery post and a battery terminal for testing results.

[jimdigs]

"crank the engine while you have your multi meter touching the positive post and the main power wire at the starter." Do you mean to touch the positive post of the battery and the main power wire at the starter?

[WmWatt]

Charging voltage is 14.7 according to the Haynes manual. You're trying to force current to run backwards into the battery so it's got to be greater than the voltage in the battery. I'd guess less voltage from the alternator = less charge at a slower build rate in the battery.

[FestYboy]

"crank the engine while you have your multi meter touching the positive post and the main power wire at the starter." Do you mean to touch the positive post of the battery and the main power wire at the starter?

Yes.

[jimdigs]

I recently swapped alternators and was wondering if I have the one single wire connected right There is a bolt that is right against the alternator then the wire is put on and then another bolt is put on to tighten it against the other bolt connected to the alternator. Does this sound right?

[william]

If by bolt you mean nut then yes that's how mine are.

[jimdigs]

I recently swapped alternators and was wondering if I have the one single wire connected right There is a bolt that is right against the alternator then the wire is put on and then another bolt is put on to tighten it against the other bolt connected to the alternator. Does this sound right?

That's what I meant. Thanks