Low voltage

[Bigsky_Boarder]

New tighter belt fixed the ac, I think the added friction when it turned on was too much for the loose belt to spin so it stopped and the squealing was the engine pulley/one that spins the rest/whatever its called just spinning against the belt that wasn't moving


Sent from my VS988 using Tapatalk

 

[Schurkey]

taking the cable off the battery whilst running to check the alternator is NOT a proper and or good test to see if your alternater is working. By doing so could actually hurt the computer. That goes for ANY vehicle that has an ecm.

No do NOT do that.... it can hurt the ecm(trucks computer).. that is not a valid test on ANY vehicle with an actual computer in it. That is the old test for carburated vehicles only as they are not computer controlled and not affected much, if at all, by any voltage spikes.

did you just seriously suggest that? NEVER do that on any computer-controlled vehicle.

This^ PLUS it also applies to ANY vehicle with an Electronic voltage regulator regardless if it has an ECM/Computer

OK, we're getting closer.

Ive done that for years. Never had an issue. I would not do it on any thing with a BCM, but on these old OBD 1, and OBD 2 systems, chances of messing something up are slim to none. Not saying it cant happen, just saying chances are it wont.

You must be registered for see images attach

This is the proper way to do the job. Removing the battery cable is not, I admit. But like I said, I have dont it for years. Never had an issue doing that. I have even had the alt stick on full charge, frying the fuseible link, ( this is on the wire that charges the battery) and melting the aluminum cooling tube it was laying on. So the alt shorted directly to ground at full charge, and even this had no effect on the ECM. Maybe I was lucky IDK.

Let's go back in time, long before there were on-board computers.

Delco-Remy service bulletiin 1.2G-73, dated 4-1-70 (long before computers,and long before transistor regulators were common on passenger cars) warns of disconnecting the battery cable to "test" the alternator.

You must be registered for see images

Because disconnecting the battery cable can cause problems with over-voltage at the alternator diodes, this would seem to apply to any vehicle with an alternator. The battery explosion risk,along with over-voltage (voltage spike) of other system components make this a risky procedure for any vehicle at all--including those with old-style DC generators that don't have diodes.

 

[kennythewelder]

OK, we're getting closer.




Let's go back in time, long before there were on-board computers.

Delco-Remy service bulletiin 1.2G-73, dated 4-1-70 (long before computers,and long before transistor regulators were common on passenger cars) warns of disconnecting the battery cable to "test" the alternator.

You must be registered for see images

yea,yea,yea, and you are no supposed to change you tire size, remove you cats, install a CIA, modify you ECM, program your ECM, install a high performance cam, ECT,ECT,ECT, but people do these things every day. Like I said, I have done that for years. There are videos of people removing the positive battery on you tube. Like I said, it is not the best way, or the way a tech will do it, but if your in your drive way, and cant get your truck down the road, and have no other way, this will, and does work. Again like I said before, the chances that it will fry you ECM, or anything else are very slim. The ECM, and other electrical components are just not that sensitive. You can do what ever you want to with your truck. I know I will with mine. One more time, if I had not done this numerous times, I would not have posted it.

 

[kennythewelder]

OK. So 5 different videos of people removing the battery cable with the engine running, and no failure. I could not find one where the engine dies. though I admit. Of course there is tech bulletin telling you not to do this. This is a drive way, way to do test the alt.

xc_hide_links_from_guests_guests_error_hide_media

xc_hide_links_from_guests_guests_error_hide_media

xc_hide_links_from_guests_guests_error_hide_media

xc_hide_links_from_guests_guests_error_hide_media

xc_hide_links_from_guests_guests_error_hide_media

 

[Schurkey]

So your defense is that Youtube doesn't have a moderate proportion of idiots who don't know what they're doing, posting videos and claiming to be experts?

Just let it go. I am.

 

[kennythewelder]

So your defense is that Youtube doesn't have a moderate proportion of idiots who don't know what they're doing, posting videos and claiming to be experts?

Just let it go. I am.

No thats not it at all. AGAIN,ONE MORE TIME...I HAVE DONE THIS FOR YEARS!!!!!!!

 

[kennythewelder]

As for letting it go, hey you called me out, I did not start this. I was a mechanic at a Lincoln Mercury dealer in 1977, what were you doing then. You should not just assume someone else is an idiot, just because they don't follow protocol.

 

[Sleeper Van]

Started my truck the other day and my voltage is in the red zone, speedometer and tach move with the blinkers, windows take forever to roll up ect. The battery is fairly new, what are the other basic things I should check that would cause this?

First off I would disconnect the battery and bring it up to a full charge slowly! Then do a test on it to see if it draws down quickly. If you don't have a load tester then bring it to Auto Zone fully charged and ask them to check it for you. They do this free of charge so it's worth the trip.

If it checks out to be ok great if not replace it no matter where you buy it. Just be sure to get one that is for your vechiel, don't get the cheapest one.

Next before you install the battery trace down all your grounds. Start with the main one from the battery then check out the ones that should be from the engine to the firewall and the frame. Check out the ones in your trunk that goes from the wiring harness to the body. You should have at least one good one there. If you are unsure of weather or not they are good grounds take them off and scrape off the paint and use a cutting lock washer that has a bunch of sharp nibs that should cut into the paint and give you a good ground.

Next thing to check is all your light sockets. Rusty sockets can cause all kinds of electrical problems. Clean or replace them if they are really in bad shape. Don't forget to clean the bulbs too! If they are corroded throw them out and install new ones.

Now one more thing to check before installing your battery. Your starter should be checked out to make sure that the wires have good clean tight connections with no corrosion. Don't go crazy tighting down the wires to the post as most are made of plastic and they snap fairly easy.

Now after you have checked everything out install the battery and test all your circuits. If everything is bright and working as they should be Fantastic!!! If not then it's time to check the alternator. With the engine running disconnect the negative battery terminal, if the engine keeps running and in fact it increases in speed then everything should be good to go. If the engine dies as soon as you disconnect the negative battery terminal then you have a BAD alternator!!! Leave your battery disconnected. Go buy a new alternator, don't forget to bring your old one for the core charge and to match it up to yours. Installation is just the reverse, reconnect the battery, start it up and make sure that you have anyware from 12.9-14.1 volts at the battery with the car running. Clean up All your tools and enjoy your ride!!!

Different cars have different charge numbers at idle. So don't freak out if you're only getting 11.8 at idle. Rev it up and see the difference in voltage. Happy now? It should have been getting higher and higher as the ebgeng speed increases.

If you're still having issues with the lights your going to have to chase down each wire to find out why your having an issue. Be patient this can take time and could be your turn signal switch, headlight switch ect. Most likely its one of the things I mentioned earlier. Or you can give up and pay $400-1000 dollars or more to your local garage or dealership, myself I like a challenge and even after doing this for 45+ year's I still learn something new every day I pick up my wreanches!

 

[Bigsky_Boarder]

First off I would disconnect the battery and bring it up to a full charge slowly! Then do a test on it to see if it draws down quickly. If you don't have a load tester then bring it to Auto Zone fully charged and ask them to check it for you. They do this free of charge so it's worth the trip.

If it checks out to be ok great if not replace it no matter where you buy it. Just be sure to get one that is for your vechiel, don't get the cheapest one.

Next before you install the battery trace down all your grounds. Start with the main one from the battery then check out the ones that should be from the engine to the firewall and the frame. Check out the ones in your trunk that goes from the wiring harness to the body. You should have at least one good one there. If you are unsure of weather or not they are good grounds take them off and scrape off the paint and use a cutting lock washer that has a bunch of sharp nibs that should cut into the paint and give you a good ground.

Next thing to check is all your light sockets. Rusty sockets can cause all kinds of electrical problems. Clean or replace them if they are really in bad shape. Don't forget to clean the bulbs too! If they are corroded throw them out and install new ones.

Now one more thing to check before installing your battery. Your starter should be checked out to make sure that the wires have good clean tight connections with no corrosion. Don't go crazy tighting down the wires to the post as most are made of plastic and they snap fairly easy.

Now after you have checked everything out install the battery and test all your circuits. If everything is bright and working as they should be Fantastic!!! If not then it's time to check the alternator. With the engine running disconnect the negative battery terminal, if the engine keeps running and in fact it increases in speed then everything should be good to go. If the engine dies as soon as you disconnect the negative battery terminal then you have a BAD alternator!!! Leave your battery disconnected. Go buy a new alternator, don't forget to bring your old one for the core charge and to match it up to yours. Installation is just the reverse, reconnect the battery, start it up and make sure that you have anyware from 12.9-14.1 volts at the battery with the car running. Clean up All your tools and enjoy your ride!!!

Different cars have different charge numbers at idle. So don't freak out if you're only getting 11.8 at idle. Rev it up and see the difference in voltage. Happy now? It should have been getting higher and higher as the ebgeng speed increases.

If you're still having issues with the lights your going to have to chase down each wire to find out why your having an issue. Be patient this can take time and could be your turn signal switch, headlight switch ect. Most likely its one of the things I mentioned earlier. Or you can give up and pay $400-1000 dollars or more to your local garage or dealership, myself I like a challenge and even after doing this for 45+ year's I still learn something new every day I pick up my wreanches!

It turned out to be the alternator, but I'll remember this if I have any future problems


Sent from my VS988 using Tapatalk