Alternator not charging the battery

wickerman · 01-15-07, 04:40 PM

Just like the title says, alt doesn't seem to be charging the battery. I know the battery will hold a charge, and it's a new alternator, so I doubt that's the problem. I also think that the alt is probably charging the battery to some extent, however the addition of an electic fuel pump to the alternator circuit by the PO is where I'm thinking I'm running into trouble. Currently the fuel pump is hooked up to it's own line running to the accessory circuit, however, he's also managed to cut one of the leads from the alternator and wired that in there too. Thing is, stock wiring diagrams don't help me too much and I'm not really good with car electronics...

So anyway, I've got some reference pics I took this afternoon.

Pic #1:
http://wickerman.cl.msu.edu/fj40/alt1.jpg

Here you can see the aftermarket alt, and where the PO cut the line and wired it off to the left (The green is the fuel line to the new, electric pump

Pic #2
http://wickerman.cl.msu.edu/fj40/fuelpump.jpg

Here's the fuelpump, heap of crap that it is. the brown and white lines are positive and negative that head off to the accessory circuit in the fuse panel.

Pic #3
http://wickerman.cl.msu.edu/fj40/alt2.jpg

This is just another angle on the Alternator.

Can I just cut his stupid wiring from the alt to the fuel pump and wire it back in where he cut it in the first place? I can't see any reason why he did it that way, as opposed to tying the fuel pump in somewhere else (which he did anyway). Also, I'm planning on putting a mechanical fuel pump this summer so this is more of a short term thing (aren't they all). I'd just like to not have to leave it plugged in every night until then.

Any insight is apprecaited.

Pin_Head · 01-15-07, 05:43 PM

Can't really tell what is up with the wiring just by looking at the pictures, because it is not stock. What year is it and what kind of alternator? Why not just measure the voltage across the battery with the engine running at 1500 RPM? It should be greater than 14V, and if it is, the battery is charging. It isn't clear why you think it isn't charging.

Just from looking at the pictures, it seems to be an internally regulated alternator and it may be energized from the Acc position of the key (as is the fuel pump), which would explain why it is wired like it appears.

wickerman · 01-16-07, 07:12 AM

Thanks for the reply Pin, it's a 1980, and very little on it is stock.

It's a NAPA alternator, I don't have the part number on me right now (I'm at work). What I think is happening is that the accessory circuit (where the fuel pump is connected) is draining the battery or sapping too much power from the alt to effectively charge the battery. I also noticed after my first post that the Amp gauge in the cab is not registering anything, so I'm pretty sure that's the wire that is cut (the black wire bundled with the white, you can see it in alt1.jpg).

I'll check the volt readings at the terminals this afternoon, but last I checked it was around 13.5 (but that was before I replaced the Alternator).

The connectors for the alternator are all stock, they're just hacked up so if you can identify which is supposed to go where I might be able to get it figured out. This is my first FJ so I don't have much experience with what a stock setup is supposed to look like.

Clyde-2 · 01-16-07, 07:34 AM

I just went through this last summer. Just because the alternator is new does not mean it's good. I had a new one and it was no bueno. Have you had it tested ? When your engine is running can you hold a screw drive to the back of the alternator and feel magnetism that is being generated by the alternator ?

nuclearlemon · 01-16-07, 07:36 AM

test your battery connector on the positive side both on and off the battery. that will help tell you if the alternator's putting out.

Pin_Head · 01-16-07, 09:45 AM

Quote:

Originally Posted by wickerman

It's a NAPA alternator, I don't have the part number on me right now (I'm at work). What I think is happening is that the accessory circuit (where the fuel pump is connected) is draining the battery or sapping too much power from the alt to effectively charge the battery. I also noticed after my first post that the Amp gauge in the cab is not registering anything, so I'm pretty sure that's the wire that is cut (the black wire bundled with the white, you can see it in alt1.jpg).

I'll check the volt readings at the terminals this afternoon, but last I checked it was around 13.5 (but that was before I replaced the Alternator).

The connectors for the alternator are all stock, they're just hacked up so if you can identify which is supposed to go where I might be able to get it figured out. This is my first FJ so I don't have much experience with what a stock setup is supposed to look like.

Hard to tell what wires should go where w/o knowing what type of alternator it is. The large white wire with blue stripe is the alt power output to the battery. If you are getting over 12 V, the alternator is working. Check the amp meter fuses. They are located in line with the wires near the fusible link at the battery + post. One of the amp meter wires is black, which is one of the few toyota wires that is black.
I wouldn't go cutting wires if you don't know what they do and where they should go.

There is a schematic diagram here:
https://webfiles.uci.edu/cglabe/Phot...g?uniq=-awot9x

wickerman · 01-16-07, 10:47 AM

Thanks a ton guys, I'll try some stuff and update later tonight!

PabloCruise · 01-16-07, 12:22 PM

Quote:

Originally Posted by Pin_Head

It isn't clear why you think it isn't charging.

x2 - what are the issues?

wickerman · 01-16-07, 01:12 PM

The battery isn't recharging. If I keep the battery on a charger when I'm not driving it it's fine, but I can only get a couple of trips to/from work before it doesn't have the power to turn the engine over.

I put the battery on a trickle charger for several days and once the battery was fully charged I took it off for a few days and the car fired right up, so I know that when the car is off, there is no short draining the battery and the battery is not shorting out internally. I can pull the cable from the battery while the car is running and it doesn't die, so I know that the alternator is providing enough power to the car to keep it running.

As is sort of visible in the pics, the wiring job is terrible, but it's what I've got to work with for the time being.

Is the black wire on the stock harness for the alternator (the one that is cut, and would head to the green plug on the alternator) handling the amp meter in the dash? Since the Bat + is hooked up to the stock wire. I'd think that the connection to the battery is fine, however the voltage regulator connector (green plug, right?) are what's cut and heading to the fuel pump.

I'll get some vdc readings from the battery terminals tonight. anything else I can check/take pics of to help clarify things?

Pin_Head · 01-16-07, 01:18 PM

The schematic does not show a black wire connecting to the alternator. The amp meter connects to both ends of the fusible link which is right off the battery + post. There should be two fuse holders in the vicinity of the fusible link.

wickerman · 01-16-07, 03:56 PM

I just took a volt reading from across the battery terminals, under load (lights on, fan on high, engine at ~1500) and got 11.95, so it's definitely not charging the battery.

The cut wire that I said was black, is in reality the black/yellow line from the "IG" point on the internal regulator to the fuel cutoff solenoid and then to the 10A engine fuse on the panel. The White/Lavender line is intact, and it should be making it's way to the battery by way of the ammeter, and a fuseable link.

I did find the fusable link and sure enough the fuse was blown. I replaced it and that seemed to fix things, I'm now registering above 12V consistantly, however I still have no response from the ammeter in the cab, which is a bit bothersome. At the point where I remove the fuel pump and revert it to the mechanical stock varitey, is there any reason why I can't just put everything "back the way it was?"

Again, thanks for the help guys!

Oh, and finally, I found this wiring diagram to be really helpful as well.
http://wickerman.cl.msu.edu/fj40/fj4...ng_diagram.pdf

Pin_Head · 01-16-07, 04:40 PM

You can wire it like it was supposed to be and this would be desirable. The hard part is figuring out how it is wired now.

The black/yellow stripe wire is from the engine fuse (key on) and it is used to energize the internal regulator alternator. It connects to the IG terminal of the alternator. the internal regulated alternator was optional for cruisers in frigid climates.

If the fusable link was blown, your truck wouldn't run, so I am not sure we are talking aboutthe same thing. It is a short lenght of strange wire that comes off directly from the battery + post. The amp meter connects to both ends of the fusable link. It has two 5 amp fuses in line on both leads.

The wiring diagram you have is for a '78 and there are several things that are different in 80 and later cruisers.

Here are schematics for an 81, which shouls be the same as your 80:
http://members.cox.net/cglabe1/Photos/fj40scheme3.jpg
http://members.cox.net/cglabe1/Photos/fj40scheme2.jpg
http://members.cox.net/cglabe1/Photos/fj40scheme1.jpg

wickerman · 01-16-07, 06:57 PM

The yellow/black line is the one that's cut (on the harness side) and has been rewired into the positive feed from the accessory circuit to the fuel pump. the ground for the fuel pump goes directly back to the accessory circuit. there is a fusable link in-line from the fuel pump to the accessory circuit (this is totally not stock)

The other fusable link (the one about 2" away from the + terminal on the battery) will blow anything less than a 25A fuse immediately, and won't keep a 25 for more than a couple of minutes. I've been keeping a 30A in there, but that doesn't last too much longer. I agree that it might not be the fuse for the ammeter since there's only the side of the fusable link away from the battery connection has more than one wire coming off it. Also, when that fuse is blown the truck still runs. I did notice that before the fuse blew the battery was registering above 12V, it was still bad, but it was better.

I'm not seeing any other fusable links in that area of the engine compartment. Are the ammeter fuses located on the cab side of the firewall?

Also, my truck did have the internal VR stock.

grant5127 · 01-16-07, 07:50 PM

One thing wrong with this picture, is the alternator is clocked wrong for this application.... you belt tension adjuster is all the way out.....if the voltage regulator was over around the 1 o'clock position you could install the correct belt.... nothing to do with charging, but could be a better fit

Pin_Head · 01-16-07, 08:15 PM

It is probably OK to run the alternator off the accessory fuse. This doesn't explain your problem. No telling why the PO cut the other BY wire. Is there 12V at the end of the wire with the key on? What is the resistance between the BY wire and ground with the key off?

A fusible link is not a fuse. It is a short piece of wire that melts before the rest of the wire burns up. The one on FJ40s is about 75 amps. Post up a picture of it.

Here you go for a picture of fusible links.

http://www.madelectrical.com/catalog/fusible-link.shtml

wickerman · 01-17-07, 02:13 PM

Quote:

the alternator is clocked wrong for this application....

Yeah, I know, the Clocking is adjustable on the alternator, Once I get the wiring squared away I'm going to turn it.

Pin, Thanks for clearing up the fusible link confusion for me. I was thinking that you meant an inline fuse holder. I'll take another look at it when I'm out there. What's there might very well be something the PO added. There's not supposed to be an inline fuse holder next to the +terminal on the battery, is there?

I'll check the other stuff and post back this evening.

Pin_Head · 01-17-07, 03:29 PM

Post up a picture. If it is in line with a large (8 ga) white wire, then this is the main chassis feed and if this fuse blows, nothing works. It could also be the fuse holder for the amp meter, but there should be two of them.

wickerman · 01-17-07, 04:05 PM

Looks like I got it squared away. I found a double fuse holder which I believe is for the ammeter. They both looked ok. the fuse holder in question is a black, and it definitely doesn't kill the engine when it's not running.

Anyway, I started the truck and and was testing voltages and decided to disconnect the fuel pump/red wire connector while it was running to see if it died or any any effect on what I was reading across the battery terminals. I disconnected that, and it didn't die, so I checked the reading at the terminals and it had jumped up to 14.2V! I then checked the cut wire (Black/yellow) and the connector at the alternator and I was getting .2-.4 off the IG on the alt and nothing on the black/yellow, so I wired those together. As it stands the alt circuit is back to original wiring, and the fuel pump is heading directly to the aux circuit. I killed the engine and tested voltages with the key on and off and everything looks like it's back to normal.

I'll try to get a pic of the positive cable spider's nest tomorrow or shortly thereafter, it's pretty messed up as well, but I don't think it's causing any problems (yet). I'll start a new thread to investigate that one though.

Thanks again to you guys for the education and all the help!