CaseyH

I need to figure out what the problem is with my car. My car died at a stop sign today. I noticed before my car died while I was driving that the CD player was not on. I wasn't sure what the problem was at the time, but when I tried to start the car it would make a clicking noise. I called my Dad and he came and we jumped the car. The car started up and I thought that I would be able to get home. I made it a couple minutes, not going very fast because the roads were really slick, before the car died again. We were in a pretty safe spot and I didn't want to risk the car dying on a busy street, so I called a tow truck and brought it back to my house.

Does anybody have any idea of what the problem could be and what I can do to fix it?

Thanks

soupcan

Sounds like the alternator is not charging the battery.

michaelathome

+1 what the soupman... I mean what soupcan said or a really dead battery not taking a charge at all doubt that it woulda run at all had that been the case so again back to what soupman said.

Michael

CaseyH

I thought it might have something to do with the alternator, since I've had problems with it before. So you guys think replacing it should fix the problem?

dr bob

Diagnose first--

--Remove the battery from the car and check the fluid levels. Make sure cells are filled, use distilled water to top up as needed. Fluid levels below the tops of the plates = very bad.

--Charge the battery, still outside the car. Use a commercial battery charger you can buy at Wal-Mart or the local auto supply store. Doesn't need to be fancy. A four- to six-amp charger will be handy for a long time, and should charge the battery in 24 hours. Does battery acccept a charge? Check with a voltmeter after battery stops charging, plus an hour. Voltage should be 12.5+. If voltage is lower, it's time for a new battery.

--You should also check the density of the electrolyte in the battery after it's charged. Cheap tester (<$5) from the auto parts store should be part of your tool collection anyway. The one with the little ***** is fine. If --any-- cell is weak or even marginal, it's time for a new battery.

--Clean the battery terminals with a battery terminal brush until they are bright and shiny. Even a new battery needs this. Do the terminals on the ends of the cables too. Grey is not OK, bright and shiny please. OK to use a little emery or sand paper for this.

--Clean the battery well. Paint if necessary.

--Install the battery and make sure it's bolted in securely. Positive cable attaches first, then the negative ground strap. Once the cable connections are secure, protect them with a thin film of Vaseline.

--Be sure to connect the vapor vent hose. If you don't have one, a short section of plastic tube can be used to route the fumes from the vent port out of the battery well.

--Start the car, and use the voltmeter to see what the battery voltage is. Should be 13+ at idle, 13.5+ with engine above 1500 RPM. If voltage is still low, you likely need an alternator. However, your symptom of no radio operation points to a possible problem with the ignition switch. The alternator needs a little kick in the pants to get started charging. That kick is delivered through the alternator charge light in the dash prior to engine start, and for the first few seconds until the alternator self-excites while spinning. Verify that the alternator light works OK when you turn the key on but before the engine is cranked to start it. If it doesn't, you probably need to look at replacing the electrical portion of the ignition switch. There are a few detailed tests of the switch you can do, looking for voltage on thge 15 bus in the CE panel with the key on. This will tell you for sure that the switch is or isn't working right.

HTH!

CaseyH

I should also mention that this battery is nearly brand new. When I first got the car(August 2006) I discovered a slight drain on the battery, so if the car sat for a week the battery would be dead. I found a few things that I thought might have diagnosed the problem(red warning light in door), and at the time the battery in the car was also almost brand new.

At that point the battery had been completely dead so many times I decided to exchange it for a new one. I've been driving the car every day for the past few months now without any problems, besides the occasional alarm-related problem.(https://rennlist.com/forums/928-forum/350817-more-problems-with-car-intermittent-no-start-rv.html) But the entire time I've still been getting the drain. Could any of these be related? It'd be nice to kill two or even three birds with one stone, but that rarely happens with a 928.

I'll follow your steps Bob.

Thanks

CaseyH

I got my hands on a voltmeter and started up my car. The voltage was around 12 and was not going up. It looks like I'm going to need a new alternator. Just to make sure I was going to remove the alternator and go have it tested. Is there a guide on how to remove the alternator? Does it say anything in the workshop manuals? I've never removed an alternator before, but it seems like it shouldn't be too difficult.

Thanks

Mrmerlin

to remove the alternator DISCONNECT the BATTERY first. with the front of the car on jackstands remove the engie pan cover if you have one. Rmove the air inlet hose, and the lower alternator tension bracket and belt from the engine. Remove the top pivot bolt ,its a long one and you may have to force it past the rad hose, once the bolt is out the alternator will drop out put it on a support like a small box so the wires arent stretched, remove the rear air inlet cover and note its position it will fit 4 ways and only one will work. Remove the 2 wires noting the locations .
On the bench look at the bask of the alternator if its a Bosch then you can remove the 2 screws that hold in the brush/regulator assembly, inspect the brushes for wear if one is shorter than the other then you may need new brushes, it is easier to just replace the whole regulator with a new one. If the brushes look good then reassemble the holder to the alternator and take it to have it checked. Installation is the reverse of disassembly. Also now is the time to inspect the power steering lines any that are wet should be replaced, unless the lines are new and the clamp is loose

CaseyH

I finally got a chance to go get the alternator tested. As I figured it would, it failed the test. I do have a Bosch, and the brushes do appear to be worn. Is it possible to just get new brushes, or do I have to get a completely new regulator? I wonder what the price difference is; the regulator is about $70.

CaseyH

Well, seeing as a new regulator was $70, and I wasn't sure that was the problem, I decided to go with a rebuilt here in town with a 2 year warranty. I installed it yesterday, and started it up with the meter on the battery and voltage was still around 12 and not going up. Any ideas?

Thanks

Art20c

do you see any difference in voltage when measured with engine off and engine running?

Mrmerlin

I think you should clean all of the elex connections before testing your charging system including the hot post, As usual Disconnect the battery first

joejoe

Probably a dumb question, but does the low charge light come on when key is turned on (not start position) The excitor to start charging goes through this light and resistor. No light, no charge. When I upgraded my '81 from paris rohn to bosch I had to upgrade the resistor also. If not then high revs are needed to start charge. Hope this helps.

CaseyH

The light comes on. I put the meter on it again today and started the engine. Voltage went down. I revved the engine and the voltage went up to 15. I thought it was a good sign, but I let it idle for a couple seconds and it dropped back down to 12. I revved it again it didn't go up. I revved it a few more times and it didn't go back up. Any ideas why the voltage would go up on the first rev but it wouldn't go up after that? Bad rebuilt?

CaseyH

Alright, I had another mechanic friend of mine look at it today. This time while I kept it right around 2,000rpm while he was testing it seems like the alternator is good. He said the voltage stayed right around 15, and he thought that seemed too high. He recommended adding an external regulator because he was worried about the battery being ruined. Any thoughts?

Thanks