RTH - Alternator or starter problem - TIA (1 Viewer)

96LandcruiserPJ

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I tried searching the forum and found a lot of great information, but something is not connecting for me.

Our FJ80 is under 200k miles, has a fresh battery (less than 2 years) and all new battery cable terminals. The battery reads 12.6v (direct contact voltage meter) when I checked it (yesterday and this morning), but the vehicle doesn't start sometimes. This morning I checked the battery and got 12.5v before I tried to crank it, but I couldn't get it to turn over. I watched the voltage on the ScanGauge II drop to 10v after two attempts. It seems to start better when its warm, but this has been a problem for a couple of weeks.

Its now been an hour or so since the last attempt. The battery checked in at 12.3v, and so I tried starting it, - ScanGauge II showed 10v after two attempts.

Current temperature here is in the high 40's in the morning.

Is this the starter or the alternator?

We are planning to head to Arizona with some friends in a couple of weeks and we need to know how to solve it. I have a call in to Yotamasters, but it would be good to be properly informed.
 

flintknapper

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The alternator has nothing to do with the ability of the engine to 'crank' (aside from not charging the battery).

A two year old battery is far from being 'fresh' and I would first look at all connections (leads and grounds). Have your battery load tested (resting voltage tells you little).

If you can jump start the vehicle then I would be inclined to suspect the battery or poor connections. If (with a good battery) your engine cranks slowly or you hear a clicking sound from the starter (or NO sound) then I suspect your starter (most likely the solenoid contacts).

You'll also want to look at your fusible link at the battery. Once started...you can check the voltage output of your alternator.
 
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Doesn't start or doesn't crank?

Battery should be near 12.8V to be fully charged - for a standard wet cell battery.

When was the starter last changed/replaced/repaired? Given you have owned it from nearly new.

When running (I'd try to jump start it), battery voltage should be near 14.4V with the alternator working properly at say 1500rpm on the engine.

Battery dropping to 10V - does it recover quickly or stay at 10V for quite a while? I'd also measure that on the battery posts and not with the scangauge...

cheers,
george.
 

96LandcruiserPJ

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Just was able to start it up and drive around - could it be the fuel? We don't drive it very often and I wonder if it just is condensation in the fuel tank? I got some fuel additive and topped off the gas. Any clues on cold v warm weather starting problems?

But, I don't doubt that it might still be the starter.
 
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Don't drive it very often, voltage dropped to 10V after attempting to start, ran a little bit ago and now just suddenly won't start... Pard, the evidence points to a dead cell. LAC batteries don't like to sit.
Do you use a battery tender when its not being driven?
Do you have a battery tester? The kind that you pull the caps and measure the electrolyte.
Can you pull the battery and take it to the local parts store? They can stress test it and tell you for sure.

Have you tried to jump start it? When you get it running, what's the voltage with the engine running at 12-1500RPM measured across the posts, should be 14V-15V if alternator is running correctly.
 

96LandcruiserPJ

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Don't drive it very often, voltage dropped to 10V after attempting to start, ran a little bit ago and now just suddenly won't start... Pard, the evidence points to a dead cell. LAC batteries don't like to sit.
Do you use a battery tender when its not being driven?
Do you have a battery tester? The kind that you pull the caps and measure the electrolyte.
Can you pull the battery and take it to the local parts store? They can stress test it and tell you for sure.

Have you tried to jump start it? When you get it running, what's the voltage with the engine running at 12-1500RPM measured across the posts, should be 14V-15V if alternator is running correctly.

Thanks

1) I have not considered a battery tender, but that's a great idea.

2) I have tested the battery before starting and after starting - we are 12v before and resting right around 14v when engine is on and running,

3) Jump starting has not always worked. Its always better later in the day,

Thanks for your thoughts
 

Irish Reiver

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@96LandcruiserPJ I'm still a little confused by the terminology. You mention in your first post that at 12.5v you couldn't get her to "turn over". Does this mean it wouldn't crank or it would crank but not not start?
Also when measuring the voltage on a flooded battery the decimal points are critical. 12.8v is a fully charged battery - 12.3v is down around 65%. Starting with a known fully charged battery is a good place to start. I agree with @Rusty Marlin that a battery tender is good approach especially if the cruiser is sitting for a few weeks without being used.
 

flintknapper

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@96LandcruiserPJ I'm still a little confused by the terminology. You mention in your first post that at 12.5v you couldn't get her to "turn over". Does this mean it wouldn't crank or it would crank but not not start?
Also when measuring the voltage on a flooded battery the decimal points are critical. 12.8v is a fully charged battery - 12.3v is down around 65%. Starting with a known fully charged battery is a good place to start. I agree with @Rusty Marlin that a battery tender is good approach especially if the cruiser is sitting for a few weeks without being used.

Even a battery tender is only good for possibly one start IF the battery is not 'holding' a charge. OP needs to have the battery load tested and check each cell for electrolyte levels. Also, the battery needs to be fully charged and tested OFF the vehicle.

OP states 12 volts (resting state) which is a flat dead battery.

The other issue we have is with the terminology:

OP needs to use 'Crank- Cranking' to mean the engine will spin (by the starter) and 'Start' to mean the engine will fire up and run. Dispense with ' Turn Over' for our purposes here...since it can have two meanings.

From what I've read the OP is having issues getting the engine to 'Crank' (starter spins engine ).
 
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I'd get a fresh battery, a battery tender (Ctek makes good ones) and drive it regularly leading up to your trip. This will give you a chance to burn off the old fuel and shake out any other potential problems before heading out.
 
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Boulder, Co
Jump starting not always working can certainly be a bad starter. Either a new starter (like @BILT4ME suggests) or open up the existing one and replace the copper contacts (the contact rebuild kit is cheap, the job is pretty easy since the starter is removed anyway.)

Doing the above can resolve the issue, but there is another possibility at play - insufficient voltage making it from the battery through the starter switch, neutral start switch, splices in the harness and various connectors along the way to the "S" terminal of the starter. When the S terminal doesn't get enough voltage, the starter won't fire - the usual symptom is just a single "click". This is an age-related phenomenon. As the circuit ages, all or some of those components lose some incremental ability to deliver full voltage to the starter. I believe this problem is actually masked by the usual attempts at resolving starting problems. Trying a fresh new battery may just have enough extra initial voltage to make it through the degraded circuit to let the starter fire. Same with swapping out the starter with a new one as a new one will have no wear and therefore fire more easily even with lower voltage on the S terminal. However as soon as the new starter or new battery ages a little bit, the starting issues can return even though there is nothing wrong with the battery or starter. Some of us on Mud have chased this for years, replacing a multitude of parts in the starting circuit, but often with no long-term resolution. And, some parts of the circuit aren't so easy to replace (e.g. splice connections in the harness). Many of us have resolved this by adding a relay or solenoid into the starter circuitry to bypass the starter circuit and deliver full battery voltage to the S terminal with all "fresh" wiring. This has proven to be a solid, long-term fix for the issue, even though, yes, the "root cause" of the problem is just bypassed, not actually replaced.

If you suspect this might be the problem, a ton of good info can be found right here on Mud by searching for "ford solenoid fix" or "hot shot relay" and specifically posts from @roncruiser and @jvazquez53 on how they employed some form of this fix. I did the same and my starting problems have been completely eliminated.
 

96LandcruiserPJ

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I still expect to get this to qualified mechanic, but I did put fuel additive and fresh gas in the tank because of the amount of water vapor that was coming out of the tailpipe. The research on IH8Mud.com indicated that a stale vehicle (and gas) might have a problem with combustion,. Thanks to you guys for helping. I'l let you know what the mechanic finds.
 

clx16

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Bad batteries can and do prevent jump starting. Not always but twice in the last few years i have seen it first hand. They can have voltage and not have the amps to back up cranking over the engine. They also can "recover voltage" over time.

They will fail at a stress test. And you can keep a battery from going bad with a tender but that won't fix one you've already killed from neglect.
 

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