EFI - bad alternator symptoms?

[SC74]

I noticed yesterday when loading up from the Super Celebaration that my motor seemed flat... Didn't have any response from idle and would act like it wanted to stall. It had wheeled the crap out of it the day before and figured a ground or something was loose. When I went to take it off of the trailer at home, it didnt want to start .. Same thought - loose ground somewhere. I did get it to start and noticed my volt gauge was at 10 and dropping. I cut it off and found a loose connection at the alternator - explorer set up. I also noticed that the plastic around the screw was melted. I tightened the bolt, but no luck. Then I jumped it and checked it with a meter .. Only putting out 10V and the green wire had 11.3 coming to it.

I charged it off of another truck for 15 min so I could move it, but it seems so sluggish and wants to die as soon as you think about pressing the gas (with 12V showing on gauge but still not charging itself). Would this be a symptom of low voltage or does it sound like I have other problems too? It will rev fine in neutral, just not in gear. It almost seems likes fuel starvation problem but surely not.

 

[EFI Guy]

It's probably a symptom of low voltage. I have seen weird things happen with EFI when you start getting below 11 volts. I'd figure out your charging issue first.

Is this a 3G? If so, what kind of voltage do you see on the yellow wire?

 

[SC74]

I did not check the yellow wire, but the plastic was melted so that I had to chip it away just to get the yellow wire off.

No check engine light, but I have not checked for soft codes yet either?

 

[EFI Guy]

So I assume the plastic melted because the connection was loose not because something shorted out? Did it burn any wiring or just the connection?
It sounds like you are in the market for a new alternator. FWIW you should have battery voltage on the yellow wire.

I wouldn't spend any time trying to diagnose your sluggish running issue until you know it's charging correctly.

 

[needabronco]

I've had this happen to me. The plug to my 4G alternator had a short in it and the alternator would not charge.

The engine felt sluggish and 'off', low on power, wasn't idling very well, finally it felt like the fuel pump was going bad and it would sputter out and die. Swapped in a different battery and it did the same thing within a few miles. Fortunately my alternator was fine and a wheeling buddy thankfully had the plug I needed zip tied to his wiring harness in his engine bay (Thanks again Taad!). Once the plug was swapped over everything was charging and away we went.

 

[SC74]

I assume the plastic melted from a loose connection. All of the wires still look good and no signs of burned.

I'll have the alt checked torrow and go from there. If they say its good, I'll try a new plug from Ryan's.

Do you check the yellow wire on or off of the alt? Will it still show alt output if it is unhooked from the post?

 

[Viperwolf1]

I assume the plastic melted from a loose connection. All of the wires still look good and no signs of burned.

I'll have the alt checked torrow and go from there. If they say its good, I'll try a new plug from Ryan's.

Do you check the yellow wire on or off of the alt? Will it still show alt output if it is unhooked from the post?

Explorer alt is a 4G. Loose connection causes lots of heat. It can also damage the regulator.

Yellow wire is used by regulator to measure battery voltage (same as alt output voltage). Usually it just gets attached to the alt output terminal along with the output cable to the battery.

Green wire is used to turn regulator on (12V with key on).