4Runner problems

[green40]

We went on a trip last weekend and after 400 miles
I turn onto our street and both the battery and brake idiot lights
came on. Haven't had a chance to work on it yet but should get some time
on Sunday.
Where do I start looking?

 

[KLF]

I believe you need a new alternator.

 

[rblank]

Why would the brake light come on if it's the alternator?

I say start checking ground connections.

 

[KLF]

Easy way to test the alternator...

With the vehicle running, disconnect the ground terminal from the battery. If the engine dies, the alternator is gone. Good luck but I agree on it probably being the alt.

NO!!! Don't do this on an EFI vehicle, you can fry the ECU (engine computer) and other sensitive electronics, like possibly the stereo.

Here is why: when the battery and alternator are connected and working properly, there is a "feedback" wire from the battery to the regulator that monitors the battery voltage, and helps the alternator control the current (via voltage level) that it is sending to the system. When you disconnect the battery, if the alternator is working properly, the alternator looses that feedback, and the regulator goes to full charge, at it's highest voltage output. In SOME cases (not always) this can be over 15-16 volts, too much for the tiny circuits in sensitive electronics, and things go POOF.

 

[KLF]

Why would the brake light come on if it's the alternator?

I really don't know why the Brake light comes on too, but it does when the alternator dies. I've had it happen twice, the last time was 2 years ago.

We were in Canada (eh?) on the way back from Michigan, came out of the hotel, fired up the truck to drive the rest of the way home, and both lights stayed on. Watched the voltage gauge, it wasn't as high as it usually was, so I knew immediately what the problem was. Spent the next 3 hours driving around looking for an alternator, the dealership in town couldn't get one for me for at least 3-4 days. Finally found one at a Canadian Tire store. Changed it in the parking lot, problem solved.

And now the bearings are groaning in my non-OEM alternator. Argh...

But it could also be a bad ground, it's worth checking.

 

[JJS]

NO!!! Don't do this on an EFI vehicle, you can fry the ECU (engine computer) and other sensitive electronics, like possibly the stereo.

Here is why: when the battery and alternator are connected and working properly, there is a "feedback" wire from the battery to the regulator that monitors the battery voltage, and helps the alternator control the current (via voltage level) that it is sending to the system. When you disconnect the battery, if the alternator is working properly, the alternator looses that feedback, and the regulator goes to full charge, at it's highest voltage output. In SOME cases (not always) this can be over 15-16 volts, too much for the tiny circuits in sensitive electronics, and things go POOF.

My mistake. I thought an '85 was still carbed.

 

[green40]

So Ken, how do I test the alternator?
Should I just pull it and have the parts store test it?

 

[nat88toy]

why don't you just put a meeter on the battery with the truck running and see if you get 14v if you get 12 dead alt.

you could always do what Nate did at fg 2006 his alt kept craping out so he would just hit it with a hammer every 15 min or so you can usaly hear the engine bog down a little if its kicking in.

 

[KLF]

Yeah, you can do a simple test with a meter, check the output at the stud on the alt, make sure the engine is revved up to about 1500 rpm. Should be seeing 13.5-14V.

I do know there are testers that work while the alt is on the vehicle, but I doubt you'll find a parts store that has one for free. Taking the alternator off a 22RE is a royal PITA, it's darned near impossible to get it around the PS pump, and you can't go down because the lower rad hose is in the way. I always just drain the coolant and pull the radiator, even when I did it in that parking lot. By the time you get it out, you're not gonna wanna take the chance on getting it tested, you'll just want to buy a new one anyway.

Doesn't seem very practical to go with the "bang on it every 15 minutes" solution.

 

[Mad Jack]

Yeah, you can do a simple test with a meter, check the output at the stud on the alt, make sure the engine is revved up to about 1500 rpm. Should be seeing 13.5-14V.

I do know there are testers that work while the alt is on the vehicle, but I doubt you'll find a parts store that has one for free. Taking the alternator off a 22RE is a royal PITA, it's darned near impossible to get it around the PS pump, and you can't go down because the lower rad hose is in the way. I always just drain the coolant and pull the radiator, even when I did it in that parking lot. By the time you get it out, you're not gonna wanna take the chance on getting it tested, you'll just want to buy a new one anyway.

Doesn't seem very practical to go with the "bang on it every 15 minutes" solution.

I so agree with this!!! It is so brutal to get out! I have always used a meter to determine this as well. Just like KLF states...13.5 volts to 14.

 

[green40]

Thanks guys.

 

[green40]

So I bought a new Alt. last week and finally got
around to working on the truck.
It's been sitting for 2 weeks, started right up and all the idiot lights
went out like they are supposed to. What the @$#*!
Got out my meter and I'm getting like 12.5 volts with the engine off
and 14.6 with it running. So I'm guessing the Alt is ok. Should have tested before going to the parts store.
On to
project 2, an exhaust leak at the Cat. the front flare is cracked so I'm
going to remove it and see if I can hit it with the Mig. The metal there
is getting pretty thin so I won't be to surprised if it doesn't work.
Did get to drive the 40 across the yard and park it on a 3' snowbank!
Wohoo! winter wheeling : )

 

[4traxx]

I was able to go to my good local parts store & get a flange repair kit . Its 2 halves that go behind the original flange . It worked good on my 4runner .

 

[landtank]

I'm not sure about your 85 but the newer Toyota's have replaceable brush kits for like 25.00. Real simple to put in and it almost always takes care of the problem. I personally replace them regardless between 100k and 120k.

 

[KLF]

Rick raises a good point, an intermittent charging alternator usually means either a bad/loose connection, or the brushes inside are in bad shape. It's an easy repair, yep they can be replace in yours. The hard part of the job is getting the alt out and back in. The brush kit is actually only about $15, last time I bought a set.