Trail side with a dead 4runner

[kilowhisky]

So I’m out in the desert currently in so cal and the truck is dead. I was up in the dunes and took a good hit to the front. As soon as I did the tack died. The battery light and the abs light came on. The truck was still running properly though. I got off the dune and my buddie said to try and restart it to see if the gauges come back. When I attempted to the starter just clicked. It took a jump to get running again but when we did the tack started working and everything was ok.

We started coming off the hill and the truck was fine with good power. About half way down bumping around the tack died again and the lights came on. The truck was still running so I said screw if and kept heading back. At this point the truck went into this limp mode where I was getting no throttle more than slightly above idle.

We get back to camp and the thing won’t start at all unless we use a jumper box and even then it’s saying the alternator isn’t charging.

Could I have fried the alternator or did I knock a connector or something loose and in the nearby electrical panel?

It seemed to be working ok for a bit before it got bumped again and went dead.

 

[jgue467]

I'd start by checking the battery terminals, one may be loose. Then move onto other electrical connections one by one. Luck. :cowboy:

 

[gamefreakgc]

Do you have a way to read codes? Tach dead maybe means the crank sensor? But then it would not start again...

Really really hard to say without knowing the codes.

 

[kilowhisky]

Everything checks out good with battery terminals. If I start with a jumper pack and remove the positive from the battery and keep it connected to the fuse box while truck is running it dies. Seems to indicate alternator. Is the alternator always charging or does it need to be told to charge?

The jump box says I’m not getting more than 12v when it’s connected and the truck is on.

No check engine light. That means no codes right?

 

[97LtdToy]

Ground wire somewhere knocked loose maybe??

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[Bumbo]

You say a jump gets it going and the connections are good... Perhaps the battery itself has an internal fault or short?

 

[Dezert4Runner]

Alt not charging should trip the battery light. If no battery light and still not higher than 12v when running is very strange. I’m no electrical guru but perhaps disconnecting the 20amp EFI fuse for 1/2 hour to reset the ECU while you inspect everything closer is in order.

 

[spartacus]

Use a multimeter. Basically, you should see over12 volts with the car off, and over 13 volts with the car running and no loads turned on. You should also watch the multimeter while someone else cranks the car and see that the voltage doesn't drop below about 10 volts while cranking. If those things are OK, do a voltage drop test. Connect the red lead to the battery positive, and the black lead to the opposite end of the cable going to the starter, you should not see anything larger than about 0.7 volts.could be starter plunger contacts. Make sure the alternator belt is secure and not slipping.

 

[spartacus]

Alumarine is right i was wrong in suggesting to unhook the negative cable. If you do this in a 4runner the voltage regulator will spike the voltage and fry the alternator.

 

[audiness]

Sounds like the wires from the starter / alternator to your battery

 

[alumarine]

If you dont have multimeter. Jump the car start it and remove the negative battery cable if the truck dies then its the alternator(most likely).

Do not do this. Good way to fry a working alternator.
This was a valid test back when vehicles used generators.

Do as bumbo suggested and make sure your battery is not junk.

 

[Bumbo]

Multimeter is one of those tools that are worth owning... it would answer a lot of questions.

You could pick one up for pretty cheap... not the best, but sufficient for things like testing low voltage DC stuff like batteries.

Just this weekend I had a battery that was on a tender die as it kept showing in a charging status. Pulled it off the charger, let it rest, measured 10v. Instantly knew that means an internal short on one of the 6 cells. It went in the recycling pile. No need to 2nd guess things.

 

[spartacus]

Do not do this. Good way to fry a working alternator.
This was a valid test back when vehicles used generators.

Do as bumbo suggested and make sure your battery is not junk.

Alumarine is right. Dont unhook battery cables while the motor is running. Ive edited my earlier post.

 

[19963.4lsr5]

Alumarine is right. Dont unhook battery cables while the motor is running. Ive edited my earlier post.

I turn my headlights on before doing this and I've yet to blow something up. But saying that if you only see 13.2v or less on a volt meter between the battery posts and or the alternator output.....there is no need to pull a battery cable to see if the alternator is working. "It's dead Jim"


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[kilowhisky]

Got it back home.

Guy at the auto store said if the tack instantly dies and you get some lights means the alternator is kaput. Gave it a run on the tester though.

Postmortem says the impact killed the alternator and the battery gave its life getting me back to camp. Replaced both. Good as new.

Thanks for all the help.

 

[Trojan4x4]

Got it back home.

Guy at the auto store said if the tack instantly dies and you get some lights means the alternator is kaput. Gave it a run on the tester though.

Postmortem says the impact killed the alternator and the battery gave its life getting me back to camp. Replaced both. Good as new.

Thanks for all the help.

Glad you got it figured it out. For the future if the truck doesn't run without a battery (jump box) hooked up (like you jump the truck and then remove the battery/jump box), usually it's the alternator. Once the voltage drops a certain amount, non essentials turn off first (ABS/Trac, Radio, etc).