Jakkq

It seems the battery is acting up, and not holding any charge. I try to turn it over and nothing happens. I kept the charger on the battery for quite a while, and tried it again. It would turn over for one complete second, and then die again, leaving me with no power.

I am reading 11.99-12.00. I tried using my battery jumper, and that gave it enough power to do a little something, but still not enough to even get the electrics going.

I have yet to thoroughly check out the alternator (thankfully I have one on back-up). Even with driving the car yesterday, and turning it off, and disconnecting the negative cable, it still had no power this morning.

Edit: Forgot to mention, I had taken it home from the shop yesterday, and about a minute later, a wire cap fell into the throttle, forcing the car to rev. The car died before the stoplight, and it had to be jumped. Could something else have gotten damaged?

WallyP

First - Lots of differences between electricals on a 1979 and a 1995 928. Always give full info on the car when you are asking questions. Model year, USA/RoW, auto/five-speed, mods, etc.

If this is a late model ('87 - up), you need to be careful. Over-revving can be bad news on an interference engine. Over-voltage can be really bad on the ECUs.

My first step would be to look thru the tubes on the belt covers at the timing belt, and perhaps to try to turn the engine over by hand.

If all looks well there, then I would clean the battery terminals and ground cables, check and charge the battery, and try to start it.

If you need more help, please give complete info, including a clear, verbose description of what you try and what you find.

Jakkq

Sorry. I just realized my membership was inactive, so my signature with model info wasn't showing up.

It is a 1982 928S.

I will try more in the evening tomorrow, and reply with anything I found.

dr bob

Stoooopid stuff-- Make sure the alternator belt is still on the car. Serious over-rev will sometimes cause belts to come off.

But--
The no-crank symptom even after some charging tells me that the battery is bad or you have some serious connection problems at battery and ground. Worth looking at some of the simple stuff. Pull the battery out of the car and put a charger on it, only after verifying thet there is sufficient liquid level in the cells. Top up as needed with distilled water, and charge it out of the car. Many parts places will test the battery for you after it's been charged a bit.

WICruiser

I agree it sounds like battery time but also be aware that many have had problems with the battery ground strap. The ground strap can look great and still not perform.

If you have a volt meter and an extra body, charge the battery (out of the car) the install the battery, measure the voltage at the battery, then have someone turn the key to the start position while you continue to measure voltage at the battery. If the voltage starts at 12 and drops signficantly when trying to start - replace the battery. If not, try using a jumper cable from the negative battery terminal to a secure ground point and try to crank again. If the engine cranks replace the ground strap.

SteveG

Get the batt load tested. They can show 12.5V and have a weak or dead cell.

Jakkq

Just a quick check I did.

-Tried to start, and got a little bit of power. Tried a second time, and no power at all.

- Charged Battery for a little while. Read 11.88

-Put the battery back into the car and installed it, then attached a jumper pack, and attempted to start the car

- Car started up

- Tachometer significantly dropped from 14 to 12

- Revved the engine, but it did not hold well. Sounded as if the car was about to die, after taking foot off the accelerator

- Battery significantly dropped minutes later to 10, on the tachometer.

- Very poor performance and sound. Timing belt not going normal speed, but still managing

- Turned car off

- Started it again, and the electrics worked. Lights popped up good

- Tachometer set at 10

- Attempted another fire up, but not enough power to go. Voltmeter read 11.76

- Alternator belt and Timing belts intact

- Battery seemed to very slowly drop while sitting. 11.76-11.72-11.68 within 10 minutes time.

Landseer

So, you measure across battery and get about 11.5 to 12V?

It won't turn over?

Without disturbing the battery connections, measure from the battery + terminal to a good clean bolt on the frame, say, one of the studs on top of the shock tower in back.

What is the voltage there battery+ to frame, compared to the pure reading across the battery?
Should be the same reading.


If not the same, or very close, you probably have the 15th bad ground strap that we've seen here in the last year.
(they corrode to grey on one end or another due to moisture...many have failed)
Get a round cable for < $10 at an autoparts store and install it. (you can buy the $60 OEM replacement later)


Doesn't mean that your battery isn't bad, too, BTW.

neilh

+1 on what Chris said. You appear to have jumper cables, using only the black cable if it is long enough, jump the battery -ve post directly to the engine block - does it start and run now? If it won't reach, find a good clean point near the back that you can hook on to.

Jakkq

Hmm, now before this incident, I did have the car sitting outside of the shop for awhile. Snowy and cold nasty days went by. I realized when I got the car back that there was NO Hatch Seal (the long rubber seal). Moisture could have slipped in this way.

When you state "round cable" which one are you referring to?

It's a bit too cold out to try anything else tonight. I will have to see what is in store for tomorrow.

I also DO have an extra battery sitting here at home.

Landseer

I'm saying the flat ground strap, which is woven copper, fails. Intermittently, then completely.
You can buy a black battery cable at Advance Auto for less than $10.
It doesn't fit as well under the battery cover lid as the flat strap, but it works.

If you have voltage loss when measuring as I described, it suggests the cable is failing.

Did you measure it?

Mrmerlin

first you need to do the tests that have been suggested.

and if your able to,
clearly describe what you find,

your current responses are quite brief and thus lack the dialog thats needed to zero in on your running issue.


For starters try the other battery you have if its holding a charge,
add the jumper cable to the neg terminal and another ground point in the rear of the car ,
also before you reconnect the battery ground wire to the chassis make sure it has been cleaned.
What you are looking for is 12.3 volts from the battery in a charged state, if your testing is showing less than this then you need a good battery to start with,
if the engine is running you should have 13.5 Volts or more at 1500 RPM if you dont then you have a charging issue.

The more info you can provide the better it will be to point you in the right direction

Jakkq

Okay I put in the new battery, as well as a new ground strap. After taking out the previous ground strap, you could tell it was just a POS. Corrosion had broken it in several places.

Anyways, with the new battery in, and new ground strap, I used the voltmeter to read about 12.50. I started the car up and she came to life right away. I measured again while running to get around 14.40. It was running good at idle, but after I gave it some gas, it began to lose power.

After a few revs, the tachometer dropped and dropped, until it was at at about 10, and then the warning light came on, and you could notice there was hardly any power at all.

I used the jumper cable on the negative ground, while holding the other cable clamped to the well. The battery did not seem to be draining either. It held at about 12.50+.

I let it sit for awhile and gave it another fire up. This time it held at about 12 on the tachometer, and it would stay put when I revved. It sounded very firm and strong. I turned the car off and fired up again, and it read around 14.45.
I let it idle for about a minute, and the tach dropped from 14 to 12. Voltage measured around 13.71. It can't make up it's mind whether it wants to hold or not.

Landseer

Alternator failing.

Next time it happens, with car running, give alternator a bit of tiny tap with hammer.
It will probably engage and charge again, and lights will stop flashing.

Seen this happen and documented it on two occasions on our 86 car.
System is designed to flash all warning lights as voltage drops below a threshhold level.
Found that reference somewhere during my search.
Wife called me from a traffic jam heading into the Hampton Roads Tunnel last May with exactly this issue, based on your description.

Not uncommon to have multiple failures of electrical system on these cars, simultaneous.
It has been said, too, that disconnecting ground strap while running will damage alternator.

Jakkq

Well it's a good thing I bought an alternator when the sale was going on at 928 Int. I'm getting the alternator out of my 924, which I will say is a real bitch, cause there is no hand space. Hopefully this isn't as bad.

I'll mess around a bit more and see if I can find anything else too.