Charging system confusion!

Arizona_928 · 05-05-2010, 07:00 PM

I have been having what i believe to be alternator failure on my 85'. The first time i noticed it was on the way home from the drive-ins, and the battery light was slightly glowing. I popped in a spare voltage regulator and got 13.8V at the battery and that lasted for acouple weeks until i got a rebuilt in. The rebuilt only put out 12.8V but didn't triger the light until acouple weeks later. I finally got fed up with replacing them, and went to checkers and bought one of theirs. The first one they gave me was bad out of the box so I had wait till today to get it in. They put it on there machine and it passed, however at the battery I'm gettting a reading of 12.2 volts. battery is brand new of today, and checked out good just now.. I'm leaning towards another bad alternator, but could bad wiring also be a cause?

AA_Ezra · 05-05-2010, 11:29 PM

New bat should be above 12 volt so that is good. Sometimes the battery light goes on simply because the conection to the small wire from apt to dash is dirty and yer apt may be just fine. Well of never hurts to clean comtact points. Clean the power wires that go from alternator down to the starter under the car. Make sure battery ground surface to chasis is clean and clean the bellhousing to chasis ground wich is behind the intake mani. Bad ground is all it is hopefully wich could the culprit

Arizona_928 · 05-06-2010, 04:54 PM

I don't have a ground to bell housing. One of the PO's tricks when he messed up on the clutch.

I'm also having some running and starting problems with car. I can go around the block then come back home shut her down and it will fail to restart like the car is just running off of the battery.

AA_Ezra · 05-07-2010, 10:53 PM

Battery to start and apt to keep it tuning. Well if your missing it create one. The block has got to have one to the chasis. What is the output on the alternator post? Did u clean the wires on the starter b/c they go there first before charging battery

Arizona_928 · 05:58 PM

Woa long bump. I have replaced the grounds with some 00 welding wire, and cleaned all contacts at the starter, battery, and alternator. After I replaced the ground and moved up to a military style battery connectors I was getting 13.8V, then went for a short drive and on the way home it dropped back to 12.2V.

I'm getting 10V at the alternator post. I think my new alternator is bad again.

fmartenies · 07-12-2010, 06:04 PM

4 bad alternators in a row? That doesn't sound reasonable. All the alternator does is spin and generate electricity to put back into your battery via regulator/rectifier.

I can't tell from your post, is it a new battery? If so check everything inline from the battery to the alternator. Make sure nothing is grounded there or otherwise "custom" or all your charge might not be making it to the battery.

Arizona_928 · 07-12-2010, 06:20 PM

Battery is a month old. My old one failed again. Yepp I've been through 4 alternators and 3 batteries.. ha! I've checked all of the wiring, and even converted the Positive side terminal to a lug style, shrink wrapped and the whole 9 yards. I can replace a alternator in around hour now..... =D

I take it 10V at the alternator is bad?

fmartenies · 07-12-2010, 06:29 PM

Are you sure the wackjob wiring isn't draining the battery, and the majority of those alternators just couldn't keep up? I'll concede 1 or 2 may have been bad ;-)

Arizona_928 · 07-12-2010, 07:04 PM

haha. I'm building a new harness now, and will get that alternator tested for the hell of it. I've replaced the original harness with a really good used one from 20th street auto. idk the wiring isn't corroded or anything it just seems that it's the most likely cause.

John_AZ · 07-13-2010, 06:57 AM

Levi,

Compliments on the "00" ground wire and military style connectors.

Some members run the 12V wire from the alternator directly to the battery. This will bypass the starter lug connection.

Hook a new HD ground from the alternator to the block. Yes I know it is mounted directly.

Replace the tiny, thin wire from the alternator to the idiot light. Sometimes the wire is old. frayed, or the connection is bad. If this wire is bad, you will get poor charging.

Instead of the crappy 90 amp OEM Checker/O'Reilly alternator--, go online-eBay and see if Eagle Electric has a 115 amp upgrade rebuild with no core charge available for your car. Or any reputable rebuilder.
The 115 amp will help your car with old-resistance high, wires, old fuel pump that takes more amps and other things that need help.

GL
John

Arizona_928 · 07-13-2010, 10:26 AM

Quote:

Originally Posted by John_AZ

Some members run the 12V wire from the alternator directly to the battery. This will bypass the starter lug connection.

Hook a new HD ground from the alternator to the block. Yes I know it is mounted directly.

Replace the tiny, thin wire from the alternator to the idiot light. Sometimes the wire is old. frayed, or the connection is bad. If this wire is bad, you will get poor charging.

GL
John

That's a good idea. I might run some 1 or 0 welding wire just to over do it.

the tiny wire is the blue wire?

John_AZ · 07-13-2010, 10:39 AM

Quote:

Originally Posted by AZ_porschekid

That's a good idea. I might run some 1 or 0 welding wire just to over do it.

the tiny wire is the blue wire?

Yes, blue, blueish, greenish/blue anything close.

I have used a domestic car long red battery cable-----thinner than 1 or 0 stock & easier to work around the intake and firewall.

John

AA_Ezra · 07-13-2010, 01:06 PM

4 guage worked for me I used 1-2 amps kits from tsunami, Marine grade stuff so the copper wire was tinned (every single strand) to help with corosion.

Battery has 2 grounds (shorter the better) Alternator to starter, to battery all 4 guage.
Rebuilt alternator about 2-3 years old and the key
an ADJUSTABLE Voltage regulator running at 14 volts or so

John_az
How dose the 12 guage wire or so for the idiot light create poor charging if its damaged. I thought it's only purpose was just to alert you of alternator failure

Az_porschekid

Are you getting the alternators all from the same place ( bad batch comes to mind)
Back in the day when Iceshark was around (good info look him up) he mentioned that there was a batch of adjustable voltage regulators that went bad ( voltage up and down) it's possible that you got a batch of alternators that had a bad batch of voltage regulators

it's only about 20$ or so for a new one and it might be worth checking out

Maybe the alternator belt is too tight?

John_AZ · 07-13-2010, 03:18 PM

Jaime O.

In this thread, post 5 it is explained.

If the wire is damaged, cracked or shorting or bulb burned out it will affect the charging system on early cars

Battery DYING!!! need help quick!

Levi,
Have you checked for battery drain (current draw) when the car is off? Should read about 10ma. Here is a pic of mine.

John

AA_Ezra · 07-14-2010, 10:43 AM

OK well that makes a little more sense . So in other words if the bulb is out or the wire it grounding (shorting) some place then it creating a draw/leak of power

Arizona_928 · 01:52 PM

went to get the alternator tested. it's bad.... It's probably the voltage regulator. I found Daves Volvo Page, and he stocks a internal and external voltage regulator.
I did a current draw and I'm not sure if i'm doing it right, but i'm not getting anything on my multi-meter. The Battery light is still on with the car running...

I know John you've been trying to get me to buy one of those eagle electric ones forever now. I just feel guilty for spending 250$ on these Hecho en mexico junk, and not being able to use it.

Edit: How well do you think a 944 could hold up with a 175 amp?

http://cgi.ebay.com/ebaymotors/Porsche-924-944-Bosch-Alternator-175-Amp-1983-1988-/350320921075?cmd=ViewItem&pt=Motors_Car_Truck_Parts_Accessories&hash=item5190c109f3

John_AZ · 08-01-2010, 03:38 PM

Quote:

Originally Posted by AZ_porschekid

went to get the alternator tested. it's bad.... It's probably the voltage regulator. I found Daves Volvo Page, and he stocks a internal and external voltage regulator.
Fast Daves Volvo Page

I did a current draw and I'm not sure if i'm doing it right, but i'm not getting anything on my multi-meter. The Battery light is still on with the car running...

Hook your MM up like I have mine. Disconnect POS+ cable. Clamp red wire of MM to batt + post------------Clamp black MM wire to POS+ battery cable end. Set the MM to read DC amps-----start at 200ma setting. I have mine set at 20ma

I know John you've been trying to get me to buy one of those eagle electric ones forever now. I just feel guilty for spending 250$ on these Hecho en mexico junk, and not being able to use it.

$250! Did you get a bottle of premium Tequilla with it?

Edit: How well do you think a 944 could hold up with a 175 amp?

Porsche 924 944 Bosch Alternator 175 Amp 1983-1988 : eBay Motors (item 350320921075 end time Aug-22-10 17:42:14 PDT)

Answer:
High Output Alternator

OR

Starting & Charging System Troubleshooting

GL
John

AA_Ezra · 08-01-2010, 03:39 PM

150$ is a great pei e bit 185 amps. I duno about that one. I would ask them to prove it or atleast ask what rpm it hits 175. Damm local alf rebuilder pretty much avoided cranki. Mine up as if it was imlosible

AA_Ezra · 08-01-2010, 03:40 PM

If u want to just buy a good voltage red let me know. It's adjustable, inexpensive and has worked for about almost 5 years

Arizona_928 · 08-01-2010, 08:05 PM

Whoa. I just exchanged the alternator with another one from checkers. The one they gave me had been dropped, and had a couple studs bent. I took it and on the way home I stopped by the checkers by my house. They know me as the kid with the porsche.. lol anyways they recommended that I take it back and get the one I turned in as they won't warranty a dropped alternator. After messing around with the manager from that store I somehow talked my way into getting my money back and the alternator that was dropped returned as my core! Needless to say I feel like I robbed the place.

Here's the alternator. Also It just tested good over at autozone.