Slow Crank..Battery light on and Burn't Electrical Smell...???

Mornin...

Haven't driven the truck in a few days all good when parked. Today, however, was abnormally slow to crank and battery light on steady so I shut her down and had a Strong electrical burnt smell outside the cabin. Haven't dug into it yet as it's dark out, but from past experience a Battery light on has turned out to be Alternator related, however, I haven't had one with the electrical burnt smell. I'll get my multi meter out later on to do a few checks.

Any thoughts and a nudge in the right direction would be Greatly Appreciated...!!!

 

Sounds like you're on the right track, if not the alternator it could be a totally fried battery, if voltage is low and you cranked for extended time you could have also cooked your starter motor.

 

Slow to crank, but started right up...maybe a second or two longer than normal.

 

Did you notice the electric smell from the cab?

Did you drive the truck after this or no due to the battery light staying on after starting?

 

Didn't smell anything in the cab...shut it down and took the car to head out for a morning coffee..
Strong smell from engine bay.

 

May have witnessed the death of the rectifier on the alternator then.

When you have the opportunity I would see if it will restart and then check voltage from the positive lead (not the terminal) from the alternator and a chassis ground point, you should get 13.7v or so if not bad alternator.

If you're really slick you might be able to replace the specific components that failed but honestly it's probably cheapest and easiest to swap the whole thing out for new.

I'd get OEM but I'm "Toyota boxed".

 

Just hooked up the meter to battery....12.18v static
13.9v running

Started right up as per normal...fast crank...battery light out and NO burnt smell...what the hell....???

The Alternator does look like it's seen better days and probably original. I use a starter/alternator electrical shop to rebuild that does Excellent work ...probably heading to them in the near future.

 

Just did 7 start ups in the last 10 minutes ...all NORMAL and voltages where they should be....NO burn smell.

Electrical connections on the alt look like they could use some attention...a little on the Greenish Furry side.

 

Could have been an unfortunately placed spider or something.

I'd keep an eye on it but otherwise proceed as usual.

 

Copy that and thanks for your time...!!!

 

No problem, I'm sure it doesn't give you the warm fuzzies not having a definitive answer, but as long as you keep an eye out for that light coming back on while driving and don't have any more smells I would chalk it up as a freak occurrence.



If it comes back, feel free to holler at me.

 

I'd much rather have clear fail than one that goes away on it's own...what bothers me is the burnt electrical smell.
I'll remove it and send her out for rebuild ( $90 ) and clean up the electrical contacts next week.

thanks again...!!!

 

Green fur on the alternator big wire? Is the battery terminals covered with acid? Acid may have wicked up from the battery, under the insulation all the way to the alternator. Even if the battery is clean now, if at some point it was neglected to be extremely acid covered, this could have caused the wicking.

The burning smell, I’ve seen extreme cases when there’s so much acid and oxidation that the terminal is arcing between the terminal and post.

check static voltage negative post to positive post, not at the terminals. Then from the negative post to the alternator big wire post. If there’s a significant difference you probably need to replace the alternator big wire. You could clean the terminals and posts, making sure to brush off oxidation on the posts then retest. This is a bandaid. Since there’s acid at the alternator the big wire probably needs replacing.

I had a autozone alternator do this. It worked fine, then stopped working. I’d get jump started, then months later same thing. Repeat, repeat months weeks later. After dealing with their ahole parts counter dude, I’ve never stepped back into that store.

 

New battery installed just prior to me buying and posts are spotless...alternator big wire has a little green crud, but nothing major.

The alternator itself does have alot of oxidation on the outer casing though...I suspect it may be the original...I'll get it rebuilt as is probably over due...

thanks for your time...!!!

 

Your alternator could possibly need attention. I’ve seen them stuck off, not charging and stuck on, overcharging. I’ve never seen one do both. The oxidized case could indicate it stuck on and cooked itself, or for some reason was exposed to the elements. Left unattached outside or the hood was left open for months. If you have an oem Toyota alternator, don’t let your trusty rebuilder swap it for one aftermarket already rebuilt. If it’s an aftermarket, you might try to get an oem.

Toyota oem alternators seem to last forever but I’m sure like others they’ll fail.

Just because the battery appears clean doesn’t mean under the terminals the posts aren’t oxidized. Pull the terminals off, brush terminals and posts with a battery brush. Check battery cables resistance. Ground terminal to all over the place. Positive terminal to alternator big wire post and starter big wire post. Make sure those two posts are tight.

Something you’ll notice, the small ground wire that attaches near the battery. Under the lug is painted. I removed mine, cleaned to bare metal, put a copper washer under the lug to help it get a better connection. Probably not really necessary but I’m anal like that.

 

Identical problem the other day. Turns out the burning smell was the belt as the Alternator bearing seized and won't spin causing the slow to crank condition and battery light "ON". New Alt and belt installed and all seems fine.