P38A many symptoms from low battery voltage due to dead alternator

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Gord Wedman

Well-Known Member
Posts
617
Location
Chilliwack, British Columbia
Went out yesterday with the intention of tweaking my EAS settings but noticed after a few minutes that my tach and speedo had stopped working. Then I got an ABS and TC warning on the dash, four lights on the EAS control switch and the car seemed to be stuck in one of the higher gears. Windows would also not roll down. Fortunately not too far from home so limped home, shut the car off and tried to restart. Nothing but click, click. Got the Hawkeye out thinking the worst but the first thing it tells me is low battery voltage so I get out the multimeter and battery tests 12 volts, basically dead. It did seem to crank over somewhat slower than usual so I guess it had just enough life to start the car but not run it. Put the charger on it overnight and today started it up and checked battery voltage with car running. Again only 12 volts so alternator must have died. Second alternator I have had fail. Oddly enough there was no battery warning on the dash. If I turn the key to position 2 I do see the battery warning symbol so the bulb is good. So today I put in one of the alternators from a parts car only to discover it also does not work
upload_2022-4-23_14-31-25.gif
, :(. So I am off to the alternator repair shop on Monday.

Meanwhile I have purchased a 150 amp alternator on eBay for $79US with free shipping. Supposed to work but I will check it when it arrives and then have a working spare. Maybe on a long journey it wouldn't be a bad idea to carry a spare.
 
Battery is only a couple months old and charged up fully. Alternator should still put out 13.8 to 14.1 even with a bad battery. Costs me $10 to have the alternator tested so will do that. If bad, as expected, will repair depending on cost estimate.
 
Gord Wedman said:
The wire from the alternator goes directly to the battery so checking at battery is same thing. Neither wire at the alternator was broken.
Click to expand...
It's not exactly the same, you will get (minor) voltage drop if it's a healthy cable, but it's not unknown for the crimped end to corrode and even the cable to corrode internally causing much higher voltage drop.
To be sure, you need to test between the +ve post on the alternator and the alternator body.
A cheap clamp meter was a good investment, not superbly accurate but it lets me measure DC amps down a cable
 
Datatek said:
Not on mine it doesn't, plus a broken earth strap from engine to chassis with cause no charging.
Click to expand...

Well in the photo you can see the cable with the red end loops past the SAI and then over to the positive terminal. As for comments on voltage drop, when the alternator was working it was putting out 13.9 volts. I am now seeing 12.2 at the battery with the car running for a difference of 1.7 volts. You are never going to get a voltage drop of 1.7 volts over a 4ga cable that is only 16 inches long especially after I have fully charged the battery and hardly any amps would be flowing through the cable if the alternator was working.
I know it would be safer to disconnect the wire at the battery but i hate trying to reset my roof. Taking sufficient care can avoid touching the cable end to the engine.
20220424_101443.jpg
would be flowing through the cable if the alternator was working.
 
With all that dirt/sand soil in there I'm not surprised the alternators go "pop" ;)
I have had two of them go inside a year, second one was replaced FOC by my indie as an alternator is normally a "lifetime" part not a consumable.
We used to have a man locally that would rebuild your alternator and warrant it for a year but he's retired and in this "inbuilt obsolescence age" no-one took his place. :(
 
DanClarke said:
With all that dirt/sand soil in there I'm not surprised the alternators go "pop" ;)
I have had two of them go inside a year, second one was replaced FOC by my indie as an alternator is normally a "lifetime" part not a consumable.
We used to have a man locally that would rebuild your alternator and warrant it for a year but he's retired and in this "inbuilt obsolescence age" no-one took his place. :(
Click to expand...
The alternator is an easy DIY rebuild as long as the windings are OK.
 
So I took the spare that didn't seem to work to the shop along with another spare that I had not yet tried. The first spare tested bad, blown diodes, but the second one tested good so installed it. Started car and my voltmeter that plugs into the cigar socket read 14.2 volts. Whoopee, better than the old one at 13.9. Then I noticed coolant dripping down underneath the engine. Turned out the black plastic hose that runs underneath the alternator from the coolant tank to the throttle body heater block had cracked at the 90 degree bend. Must have got jostled at some point during all the alternator movements. So, take out alternator for third time, splice in a section of rubber hose with clamps and re-install alternator. Finally all good.

Now if I could just get my EAS to work 100% correctly. Recently installed 4 new air springs and the rear two corners drop down overnight. Don't think there are leaks at the inlet pipes to the bags but admit to only checking one so far. Can the valve block leak internally?
 
The eas leak could be the pipe that run to the back if there has been an exhaust leak from round the middle box area it can melt the pipes, to test mine i pulled the pipes at the valve block and put the emergency valves on and pumped it up to test.
 
brianp38dse said:
The eas leak could be the pipe that run to the back if there has been an exhaust leak from round the middle box area it can melt the pipes, to test mine i pulled the pipes at the valve block and put the emergency valves on and pumped it up to test.
Click to expand...
+1 ^^^^ Also the pipes into the airbags can be hard to insert past the second O ring leading to leaks.
 
Gord Wedman said:
So I took the spare that didn't seem to work to the shop along with another spare that I had not yet tried. The first spare tested bad, blown diodes, but the second one tested good so installed it. Started car and my voltmeter that plugs into the cigar socket read 14.2 volts. Whoopee, better than the old one at 13.9. Then I noticed coolant dripping down underneath the engine. Turned out the black plastic hose that runs underneath the alternator from the coolant tank to the throttle body heater block had cracked at the 90 degree bend. Must have got jostled at some point during all the alternator movements. So, take out alternator for third time, splice in a section of rubber hose with clamps and re-install alternator. Finally all good.

Now if I could just get my EAS to work 100% correctly. Recently installed 4 new air springs and the rear two corners drop down overnight. Don't think there are leaks at the inlet pipes to the bags but admit to only checking one so far. Can the valve block leak internally?
Click to expand...
Did you check that there were two o rings fitted under the collet before fitting the bags?
 
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