I store my 86 turbo 4Runner for the winter. I pull the battery which is 2 yrs old and keep it on a tender for the winter. I periodically reinstall battery to run the truck over the winter. now I need to jump start the truck and when I turn on my lights the truck just dies. am I right in thinking this is a alternator issue or could it be battery/ wiring issues?? any help appreciated.

 

Have the battery tested for free at local auto parts. Go from there.

:wabbit2:

 

Battery checks out ok

 

do you have a multimeter?

test the battery voltage while the truck is running and see what it is?

or pull the alt and have it tested as well.

 

I am also having similar problems.

What kind of voltage should you be seeing from the battery voltage? Around 12? And then when you race the engine, 14 or so?

I recently replaced my alternator with an O'Reilly's one, and have had my truck refuse to start on a couple of cold mornings. So I replaced the battery, but I'm still not convinced this is the problem. I put the old battery in my other car and it works fine. And the new alternator has been making odd whirring sounds sometimes.

One possibility I was thinking that if there is a battery gauge I could install that would let me monitor how many amps the battery was holding, this might be helpful (assuming there is such a thing). I really do not want to take out the alternator and test it, that thing was a huge pain to take out and put in last time.

 

problem is, to remove alt you need to remove lower radiator hose

 

Agree 110%.

Is there any way to monitor an alternator while you're driving, or is this necessary? I have a strong feeling mine is acting up.

 

actually... no you dont.

i ve done an alternator several times without removing it..

the hose bends and folds outta the way.

 

should be around 14 when running and yes you can get a in truck gauge for volt read outs but a palm one is good to have and pretty cheap. typically if a alternator is making noises thats not good. It could be your regulator but on 86-88 or somewhere in there they are internal so wouldn't matter also make sure your plugs and grounds look good

 

If the truck runs ok and then when you place a large draw on it (turning on headlights) and it dies then your regulator is probably a goner. You need to find out if your alternator is internally regulated or is it external.

Proper voltage at idle is 13.8 volts for most cars. Less, or more, that about .5volts indicates a bad regulator, or sometimes a bad wire that is broken or corroded from the alternator charge post to the battery itself.

 

I tried using a multi meter to test the output of my alternator. I set it on DC, 20 volts, and put the red lead on the + side of the battery and the black lead on the - battery terminal.

The black lead sparked badly, the idle slowed dramatically, and I only showed 5.8 volts. Between the sparking and the idle speed changing, I was afraid to try this again, for fear of shorting something out. I suspect that maybe the multi meter might be defective, it's $3.99 Harbor Freight model and it no longer seems to work at all.

 

Ok, so now Ive jumped the truck got it running, I drove it home turned off ignition and restarted without problem. then I go and turn lights on and turck nearly dies, dash dims, then all power comes back and truck continues to run. whats going on????

 

Its 1 of 2 things...
There is a ground wire that runs from the Negetive battery cable to the inner fender of the passenger side. If that ground wire has come loose, or is corroded, then thats your problem.


To tell if its the alternator, crank the truck and leave the lights off, While the truck is running, remove the negative cable on the battery. If the truck suddenly stalls and dies, your alternator could be bad. This is because the alternator is not generating enough electricity to keep the truck running. If the truck keeps running, the battery is probably the problem.

Best of luck.

 

I have heard that the test you are suggesting "removing the neg cable from battery while running" can cause problems

 

so now all of a sudden everything is good ?????? must have been a bad connection ???

 

Sounds like it. make sure everything is tight and and all the grounds are secure