Is it my starter, my battery, or my alternator

[sixstringsteve]

Is it my starter, my battery, or my alternator?

We just got the wife a '99 4runner. It's been having a tough time starting. Once it starts, everything works just fine, but it will start, then die 2 seconds later. If I use jumper cables, it'll start right up just fine. It acts like the battery is near-dead.

I know I can take my alternator in to any parts store and they can check it for me. Is there another way to tell if its the alternator or the battery without having to remove the alternator?

 

[STAG]

What's your battery voltage guage read while it does run? If it has enough battery juice to start the engine fine I would say its the alternator, or some other sensor is not working right which is causing it to kill itself, but then that wouldn't explain it running fine with jumper cables hooked up... And FWIW the whole alternator testing thing doesn't always solve the problem, with my old Chevy the alternator passed Vatozones test, but still wasn't working. So I replaced the alternator and everything worked again.

 

[sixstringsteve]

sometimes it starts and sometimes it doesn't. If I give it gas right when it starts up I can get it to start. In other words, it starts, but it doesn't reach an idle high enough to maintain it. It really acts like a dead battery. I'll check the voltage and report back.

 

[jeep-N-montero]

A cranky/faulty crankshaft sensor can cause similar issues as well.

 

[SLC97SR5]

Get it running and put a meter on the battery. You should see 13.7-14.4 vdc. This indicated shat the alt is trying to do its job. Once running, feel the alternator with your hand. It should get warm but not hot after 10 min. I had to rebuild mine after 165k.
What is you battery voltage with the truck off? You want 12ish and then with the head lights on a minimal drop.

You can also monitor the meter while cranking to see if the battery falls flat.

In short you need to throw a meter on it.

When it dies do your radio presets and clock reset?

 

[glockman]

If it is your alternator make sure you charge your battery after you replace it before you drive it. If your alt is bad it will drain the battery and the new alternator will be working overtime to charge it. I have seen brand new alternators killed this way.

 

[rollover]

You need to get a meter on it for sure like those above have said.

First clean your battery terminals. Contacts are everything when it comes to electric issues.
Use dielectric grease on them when you replace your wires on the posts.

Check you battery voltage cold (engine off).
Turn on your lights and check voltage again cold.
Start the 4runner up and check idle voltage.
Turn on your lights and check your voltage again.
Rev up the engine (2-2500 rpm's) and check voltage again.
Report back and let us know what you find.

 

[sixstringsteve]

I've been so busy working on the truck that I haven't spent much time on the 4runner. I replaced the battery last night, and it's been starting most of the day. However, on the way home from dinner tonight, it wouldn't start. Now, the 99's are famous for having trouble with the starter contacts.

However, the engine will crank over. In fact, it'll even ignite for a couple revolutions, then it won't fire up on its own. I was successful once, when I was pumping the gas, but I'm not sure if pumping the gas did a thing or not. I wonder if it's a condition of it starting when hot or not.

I would assume that bad starter contacts would prevent it from cranking alltogether.



I replaced the air filter and half of the spark plugs (I'll be doing the other 3 tomorrow). The old spark plugs didn't look bad though, so I'm guessing it's either a fuel issue, or the starter contacts are causing it to not fire.

 

[Kevin B.]

Bad contacts ought to give you the "click click click", I'd think. If it's cranking but not firing, wouldn't that be a timing/air/fuel issue? Unless it's cranking too slowly to get going, I guess. I'm no expert, just thinking aloud...

 

[sixstringsteve]

it's cranking plenty fast.

 

[SAMI]

My '99 didn't have the contacts fail, but they were a bit noisy when cranking. It also had a weird electrical issue that was fixed by replacing the battery wires and the terminals at the battery. The factory terminals are a joke, with very little contact; add a bit of corrosion to that and you have a horrible connection at the battery. IIRC, that fixed the starting issues that it had.

 

[thefirstzukman]

Throw a meter on the bat and watch the voltage while cranking, it's been a while but the Toyota needs 11 volts if I remember to run the ECM.. It will crank fine but not start due to low voltage. If you replaced the battery and it was fine but after a day states to do it again I would look at the alternator. Throw a charger on it for a few hours and see what happens.


I once had a friend who had a dead battery in his jeep and spent 3 weeks trying to gt it running after replacing the battery... 5 different mechanics looked at it and none could figure out what the heck was going wrong. He had the battery cables switched and it was cranking fine but all the electronics.. (older jeep) wouldnt work so he had no spark... Funny story, not in any way related.......

Good luck!

 

[huntinkid]

If the battery light is lit up on the dash thats an alt for sure

 

[Unimog]

Like zukman says, put a meter on the batt while cranking. I don't know what the ecu needs, but if the voltage is dropping to the 10.5-11.0 range, and it has been charged, I'd say the battery is bad.

 

[sixstringsteve]

Ok. Update.

12.4v this morning.
It fired right up, and dropped to around 11.5 for the split second that it was cranking
14.5v while running.



I'm wondering if it only has issues while the engine is hot.

 

[SLC97SR5]

Your battery and alternator sound healthy, are the cables/terminals in good condition? What about the white or red main feed to the underhood fuse box? Does it have a nice clean connection to the main bus?

How many miles are on the 4Runner? Any tune-up work done other than 3 new plugs? How old is the timing belt?

Are the spark plug leads original? They have a date of manufactuer stamped on them.

Because it wanted to start when you held the throttle open it could be a dirty MAF or a gummed up IAC, clean it with electronic safe contact cleaner.

What is the fuel level in the tank when this happens, mine has done something similar when warm on a FULL tank.

Does it have an alarm, aftermarket or factory?

-Sorry, more questions than help...bring it up and we'll get it solid! You know I love the 3.4 third gens

 

[Corbyn.]

After it starts and dies does it start the next time just fine?

 

[sixstringsteve]

Your battery and alternator sound healthy, are the cables/terminals in good condition?

Yes. I'm sure the battery is healthy, it's brand new.

What about the white or red main feed to the underhood fuse box? Does it have a nice clean connection to the main bus?

not sure, I'll have to look in to this.

How many miles are on the 4Runner? Any tune-up work done other than 3 new plugs? How old is the timing belt?

165k on the runner. Timing belt was done in 2000 at 106k. All I've done is an air filter and the 3 plugs (soon to be 6 plugs this afternoon).

Are the spark plug leads original? They have a date of manufactuer stamped on them.

Not sure, I'll check.

Because it wanted to start when you held the throttle open it could be a dirty MAF or a gummed up IAC, clean it with electronic safe contact cleaner.

Will brake cleaner or carb cleaner work, or are those noe electronic safe? I've got IPA that I could use.

What is the fuel level in the tank when this happens, mine has done something similar when warm on a FULL tank.

Tank is at 3/4

Does it have an alarm, aftermarket or factory?

I think it may have a factory one. There's a red light on the dash that blinks whenever the car is locked, but I've never heard a siren.


Another thing to notice...
Yesterday when I lucked out and got it started after about 5 tries, it started, almost died, I gave it gas, and it didn't die. It idled decent, but when I gave it gas, it stumbled a bit, almost like a miss in one of the cylinders. THe engine wasn't quite running 100% for the 5 min that followed, then it felt normal. Not sure if this is related to the problem starting or not, but I wouldn't be surprised. It started up this morning, so my wife took it to work. She'll bring it back tonight so I can tinker with it some more.

 

[sixstringsteve]

After it starts and dies does it start the next time just fine?

No. Once it starts, it'll stay running as long as I don't turn it off. WHen I turn the key off, it won't start back up (I'm assuming because it's hot).

 

[Max Power]

I would throw some money at it and buy some Toyota plug wires. I would also make sure you are using Denso or NGK plugs I have seen them run funny on Bosch and AC Delco.
If you clean the mass airflow sensor it will most likely idle high until you disconnect the Battery for a few minutes and let the computer reset.

If it cranks I would rule out the starter.

If your battery light isn't on I would rule out the alternator. (I have never seen a bad alternator on the 3.4 without the indicator light on).

I'm guessing it is bad wires or a sensor.