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New voltage regulator, now won't start?

DavePolyakov

Member
Joined
Aug 3, 2020
Location
Shoreline, WA
The battery tester at O'Reilly diagnosed a faulty voltage regulator so I ordered one from Ipd and installed it. The old brushes were worn, but still more than 5mm. I installed the new one from under the car because I couldn't see what I was doing from above and now it won't start. Just a click. What did I do wrong? It seems very simple to install. Currently, the battery has charged as I have been charging it every now and then. 1986 240 m46.
 
You say you've charged the battery: have you tested the battery to verify that it is holding the charge?

How are the cable connections to and from the battery (beware of corrosion)?
 
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The car started, the connections seemed to be loose somehow. Now my concern is why would the battery tester say my voltage regulator is bad if it's within spec? The brushes are exactly 3/8 inch long, not all the way down.
Ever since I crossed the battery terminals on accident I've been battling charging issues. First I replaced the alternator ground wire which had burned up and then all was good for a few weeks. Then one day it wouldn't start, so I've been charging it every couple of days, sometimes it would still be dead when trying to start it. I'm hoping the voltage regulator is the last piece to the puzzle but I'm not so sure.
 
Are you sure they ran the battery test correctly? It sounds to me like your battery got toasted (or was almost toasted already and you just encouraged it to death)
 
The guy who tested it seemed like the most knowledgeable in the whole store so I hope his diagnosis was right. The voltage regulator was only $11.95. When I did cross the battery cables the first thing I noticed was the rubber casing on the ground wire burning and smoking. I immediately uncrossed the wires but they were probably connected for around 15 seconds. He said my battery was in good shape and not the issue but then again, I'm not so sure. There is no date on the battery but when I bought the car it looked pretty new, with no corrosion or anything about a year and a half ago.
 
If the battery spend 15 second crossed and you burnt up insolation ide look over all the wiring before thowing more parts at it
 
Charge the battery, don't start the car then start doing a voltage drop down test. Something else is killing your battery.
 
These old cars get serious corrosion inside the cable insulation. Aggravated by 15 seconds of a short they may not want to function any more. Might be time for overall replacement. Cost lots less than a tow.
 
Ever since I crossed the battery terminals on accident I've been battling charging issues. First I replaced the alternator ground wire which had burned up ...
This most likely damaged the rectifier diodes in the alternator. It would cause problems charging the battery and, depending on the damage, could cause a high drain when off. Over time, the alternator may have degraded further due to the initial damage and high charging currents. The voltage regulator may have been damaged too.

I'd take the alternator back to the parts store and get it re-tested. It's a good idea to charge up the battery overnight since it may have been discharged by the bad alternator. Charging a completely dead battery with just the alternator is pretty stressful on the alternator.
 
I'd suggest testing or replacing several things. You need to load test your battery to find out if it can start the car. They can do that at the store. 15 seconds of reversed wiring has damaged your cables. Probably need at the very least the ground cable but maybe both replaced. Then you must test for a battery drain to make sure something didn't get damaged and cause current to flow when it's not supposed to drawing the battery down overnight. As Bob suggested I also agree with his assessment that your alternator is toast.
 
Test the battery by taking both cables off and measure the voltage across the terminals. If it reads less then 12V charge the battery with the cables off until the voltage is up to 12-13V. Let the battery sit for a few hours and measure it again.

If the battery has held the charge, disconnect the large red wire and the small exciter wire from the alternator and re-connect the battery cables and measure the battery voltage. If the battery holds the charge try cranking the engine. If the engine cranks reconnect the alternator wires and measure the battery. Then test crank again.

If the above goes well check the battery voltage daily.
 
The burnt up alternator-to-block wire acted as a fusible link and hopefully protected the rest of the wiring. Get a good alternator in there, charge up the battery, and see if it then behaves correctly. At idle, the voltage across the 2 battery posts should be ~13.5volts. If it's much lower, then it isn't charging (next suspect would be the red starter-to-alternator wire that wraps around the front bottom of the block).

You can also get a $10 cigarette lighter voltage gauge (amazon: usb car charger volt meter) to monitor voltage while driving. If you want to fast charge your phone, get the fancier $15 iphone rated version. On an old Volvo, voltage should be ~13.5 to ~14volts, and maybe a bit less when hot. On more modern cars, maybe ~14.5v. 12ish volts, or lower, means you're draining the battery and will eventually have problems starting.
 
Thanks for all the responses. Once I can find my multimeter I will test the voltage at idle and see if it's around 13.5v. It's been several months since I crossed them and I've driven several thousand miles. If it won't start one day in the future I will conduct more tests but I'm hoping the voltage regulator was the main issue. I try to park downhill so I can always clutch start it. I also can't be sure it was 15 seconds, it could have been less or more. I'm also hoping that the alternator ground wire acted like a fuse for the rest of my wires. If I did go about replacing all of the battery wires where can I find the guages of the wires I need? Thanks
 
Dave P,

So you have an INTERMITTENT NO CRANK!?

Find your meter and do voltage drop tests AND parasitic battery drain measurements.
 
If I did go about replacing all of the battery wires where can I find the gauges of the wires I need?
Easiest is to use a good wire stripper on the old wire and see which notch fits best -- you want the insulation to be cleanly cut (no pulling hard to tear the remaining bits) but none of the strands broken or nicked. Strip off a 2nd section to inspect the 1st for nicks.

In some of the Volvo greenbooks, the wire size is shown in metric cross-sectional area mm^2, e.g. "R 0.75" or "R 6.0", somewhere along the wire. Google "AWG to mm2 conversion" for a chart, e.g. AWG 18 and AWG 10 for the previous sizes.

I've also seen double sizes in the greenbooks, e.g. "R 6.0 (R 10.0)". I don't know what cases the 2nd number is for.
 
If I did go about replacing all of the battery wires where can I find the guages of the wires I need? Thanks

I would order new battery cables made up with connectors. I am sure that you can order OEM part number cables but I would just take them off and go to NAPA and find what fits. I suggest NAPA because they are probably going to have the best local length selection.

My '81 has a second wire from the + battery post to the power distribution panel on the inside fender. If you have that it will take a little local engineering to add to a generic cable.

Or go to ebay: https://www.ebay.com/itm/2-Gauge-Co...42d7a3f0b40d9e163e7b|ampid:PL_CLK|clp:2334524
 
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Ok, so replacing the voltage regulator didn't solve anything. I went skiing yesterday, all was good driving up then on the way down the pass my Kenwood cut out and then cut out again and then wouldn't turn on. My headlights also became intermittent. I didn't want to risk getting gas so I just went home. I will replace the positive and negative wires and then do a voltage drop-down test.
 
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