Alternator?
 

The battery in my son's 86 NA died today. The battery is only 6 months old. The volt meter in the dash is reading "0" but the alternator light has not come on.

I'm assuming the alternator is dead. Anyone have any other ideas.

jmd_forest

Check / Change the bulb in the dash??????

Ok Sorry just what came to mind.

Many local parts stores will test the alternators for free.

try charging the battery..and start it if the red ! light comes on then its not charging...first i would make sure that the connectors to the battery are clean..just what i would do..

Well, Knowing your mechanical and restoration skills are superior, I will offer a couple of pearls of gleaned knowledge.
1. Check for a famtom battery drain like the door light switches shorting.
2. The alternator charge first goes to the starter and then the batt. Check the wires, ends and clean the corrosion.
3. Remove the voltage regulator and if the brushes are shorter than 1/4 inch replace. Make sure you "dress" and smooth the ring sleeve in the alternator.
4. Is the belt correctly tightened?
5. Take out the alternator and have it checked at your local auto parts store.

Usually none of this helps. It just makes you feel better when you get a new rebuilt.

I went with an EBay seller that upgraded the origninal alternator 90 amp to 115 amps and no core required. I liked the idea of 115 amps due to the age of our cars and fuel pumps and such drawing more current and wires having increased age resistance.

GL
John_AZ
1988 924S + 1987 924S

I would take it to you FLAPS to have it tested (alternator). If you need a replacement, I have a couple on the shelf, lmk.

-Nick

I thought about the bulb in the dash being dead but didn't really want to tear up the dash to check it out. Belt is tight and ALL ground and cable connections were thoroughly cleaned when I had the engine out a year ago, but it can't hurt to check again. I'm going to test voltage across the battery both static and running to see if there is any difference as soon as I can get my son to take a few minutes from his busy schedule to participate. Since this is my son's daily driver I ordered the rebuilt John_AZ suggested off ebay so it gets back on the road ASAP.

Nick, thanks for the offer. I'd have taken you up on it if I hadn't already ordered one before reading your post.

I'll post back when I figure it out but the new alternator probably won't be here until Tuesday/Wednesday.

jmd_forest

The bulb in the dash is easy to test. Just click the key to the accessory position. It should light up if its good.

When mine died last month it was actually the holder not making contact with the circuit board contacts.

To make a long story and a lot of swearing later I just twisted the holder a smidge to make contact and voila it worked. Of course this was after I bought a new alternator that for some **** reason wouldn't work either till the bulb was working.

A quick test for the alt is to jump the car and put a multi-meter across teh battery terminals, should get around 13-14 volts. Less than 13 is low and more that 14.76 is high.

Quick update.....can't believe it but the alternator belt was shot, only about 1/3 inch wide left and very loose. I could spin the alt and AC by hand so there's no obvious reason so far why it shreddedlike that. My previous comment regarding the belts are tight was based on doing a timing belt tensioning in August and the alternator belt was only 2 months old then. I've got to stop buying parts until the diagnosis is complete... a $140 alternator sitting on the shelf along with a set of front wheel bearings that was actually loose lug nuts (I have to blame the son for that one, I told him not to put them on superman tight, so he didn't tighten them much at all). The delivery delay sometimes gets me to jump the gun.

I'll be swapping out the belt tomorrow and hopefully all will be well.

Thanks for all the help.

jmd_forest

Belts will do that.

It is always the fundamental stuff that is a pain, huh?

Hey look at the bright side...you got a spare now. :D

Yeah, right...like we need a full warehouse of stuff lying around, but than again look at "many944s" he's not hurting and on the road quicker than wiping snot from a baby's chin, when he has a car down. LOL

I too was having some problems with my alternator for a while until I cleaned up the connections to it. I then looked at the voltage regulator and found the brushes are getting low so I figured to just replace the thing.

I looked around on eBay and found a spec fit 130amp from Bosch. I want to know is 130amp too much power for these cars or not? If it is too much power, would the 951 alternators be ok? (115amp)

I don't know if 130AMPs is too much for our cars, but I do know that the 951 alternator will work just fine since the electricals within the car are very simular. I don't see why not.

If the 130 is too much, what's the worst that could happen? aside from blowing almost every fuse and relay.

Reason I'm leaning toward that so much is it's cheaper than the 115amp for some reason. Both are Bosch and both are OEM spec but one is just über priced over the other.

Am I missing something here?:confused:

I'm certainly not an expert on electricity, but I do know this you want to be very careful with what is called "wire capacity."

In other words, when electricity travels through out the circuitry and wiring it creates heat. If the wiring is not able to handle the amount of electricity (capacity), it will melt the insulation off of the wire exposing it which will then cause a "melt-down" of other wires around it. This can be a potential fire hazard and extremely dangerous.

I would check with an electrician as to whether our cars have the "capacity" with it respective wire gauge to support higher amps.

ROFLMAO!!

Yea, but I wrench a couple of dozen P-cars here in town, I have to be set on most spares, but it never fails...when something on one of my cars brakes, it's one of the parts I don't have in stock :) When that happens, I usually end up buying 2, one for me, one for inventory... it's no wonder my inventory grows so quickly!!

A new belt fixed things right up. Got my son under the car turning nuts and bolts and we were done in about an hour.

Regarding the 130 Amp alternator, considering it's only about 10% bigger than the 115 amp and most batteries delivers around 300+ CCA I think you should be OK.

jmd_forest

On the 130 Amp / 115 Amp ratings thats just maximum that the alternator can deliver, so if your car never sucks more than say 90 Amps (the stock alternator rating for an 84) the alternator won't deliver more that 90 Amps.

Kinda like a P car that will do 120mph max and you never get it above 65mph on the interstate.

So if you don't have a larger stereo or 10 offroad lights across the front bumper you probably aren't going to make the larger alternator work at its max, basically it'll be idling most of the time.

I'll admit I've got a 130 Amp alternator in place of a stock 90 Amp one. It was the same price and down the road I'm planning on upgrading a few electrical items that will require the additional current.

So 130amp is ok? and Like Tib said above about the melt-down of the wires, did you have to change out any wires to accommodate the new alt's power output? And how long have you had the 130amp one? What's your opinion on it's overall operating performance?

I too have just bone stock things on my car but with the mass of upgrades and accessories I want on it, it will pull more power, thus needing a better alt that can supply the demands hashed at it.