Carburetor fan possibly drains battery below 12v - ever happen to anyone else?

tvmaster

True Classic
I was just going through the Fiat factory manual and noticed that in the Electrical Troubleshooting section (page 221) they have diagnosis procedures for electrical issues you are having (no GEN light and poor charging). You might want to go through the step by step processes in there to figure out what the problems are.
I’ve been going thru their checks - but it’s a bit of a mess because the external voltage regulator isn’t in the loop anymore. I did confirm that the ‘G‘ light bulb that’s in there now is a working bulb, and that there seem to be no blown fuses.

Before I put the alligator clips on the alternator, the ‘G’ light was working, but proper charging wasn’t happening. After alligator clips, ‘G’ light is dead, and the same charging problem exists. It’s possible I shorted out the internal voltage regulator? Would that kill the ‘G’ light?

I also tried your idea of grounding to the case instead of frame: exactly the same voltage readings as if I was connecting my meter to the battery terminals, 12.31v. So no difference whatsoever.

Meter drops BELOW 12v when ignition is switched on, raises to about 12.2v at 1k idle, and 12.7v at 3k idle.
It‘s interesting that switching the ignition on drops battery voltage from 12.31 to 11.97v - that seems like a big drop to just light up the instrument cluster.

It can only be one of two things I think - bad alternator/voltage regulator, or a wiring fault of some kind?

But I’m always ‘all ears’
 
Sounds like you may need to figure out what is going on with the light first. Many alternators won't work if the light is not drawing current initially to excite the rotor winding. Have you gone through the "Light not working" troubleshooting guide yet? It would be a weird coincidence if the bulb just happened to burn out. There is nothing that you could have touched that would burn out that bulb since it is rated at 12V and that is all you have to work with. I have a feeling that outside of the big output terminal, the alternator may be wired incorrectly. First thing I would do is look for the installation instructions for that model alternator. It should tell you where the generator light should be connected. There may be other terminals such as remote sense that may need to be connected somewhere (usually the output terminal if you are not going to use it).
 

tvmaster

True Classic
Sounds like you may need to figure out what is going on with the light first. Many alternators won't work if the light is not drawing current initially to excite the rotor winding. Have you gone through the "Light not working" troubleshooting guide yet? It would be a weird coincidence if the bulb just happened to burn out. There is nothing that you could have touched that would burn out that bulb since it is rated at 12V and that is all you have to work with. I have a feeling that outside of the big output terminal, the alternator may be wired incorrectly. First thing I would do is look for the installation instructions for that model alternator. It should tell you where the generator light should be connected. There may be other terminals such as remote sense that may need to be connected somewhere (usually the output terminal if you are not going to use it).
Page 223 pinpoints four things: bulb, circuit board, wire or alternator.
I‘ve checked and replaced the bulb, it’s good.
Everything else on the cluster works, so I’m doubting it’s the circuit board.
That leaves a 47-year-old wire, or a newly rebuilt alternator as culprits.

Mr. Old Fiat guy had a bit of difficulty wiring it the first time, because an old wire had broken and was causing the ‘G’ light to not light. It’s possible that‘s broken again, or he rigged something that was a bypass. I really wish he wasn’t the only game in town, but that’s how it is. I’ll call him tomorrow, but as he’s 40 miles away, I honestly don’t know if 12.05v is enough to make it there. :)
 
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Dan Sarandrea (Phila)

Waitin' On Parts...
This is more of a system option for you, rather than as yet another tip or suggestion for a test. And maybe "Old FIAT Guy" might like this idea as compared to what he may have rigged up.

Assumptions: your current alternator is a standard Bosch "one-wire" internally-regulated alternator; the previous alternator was a Bosch externally-regulated alternator, said to have come on 73 and 74 X1/9s.

If the assumptions are correct, you could buy one of these:

The above brush set is nearly identical in fit to the brush set in your present Bosch alternator. The difference is, as electronics became smaller, Bosch was able to combine the external regulator and the brush set into one unit that fits in the same space inside the alternator as just the previous brush set.

If your Old FIAT Guy wants to, he could remove the combination brush set plus regulator now in the current alt, replace it with the brush-set-only unit from the older setup, and then retain the existing external three wire regulator. If desired, that regulator could be updated to a new generic regulator, or perhaps a new generic regulator that has adjustable voltage, like this: https://www.240turbo.com/AdjVR-0071.jpg This idea has the advantage of keeping your wiring close to factory which would make future troubleshooting easier for you.
 

rx1900

1981 X1/9
Sounds like you may need to figure out what is going on with the light first. Many alternators won't work if the light is not drawing current initially to excite the rotor winding. Have you gone through the "Light not working" troubleshooting guide yet? It would be a weird coincidence if the bulb just happened to burn out. There is nothing that you could have touched that would burn out that bulb since it is rated at 12V and that is all you have to work with. I have a feeling that outside of the big output terminal, the alternator may be wired incorrectly. First thing I would do is look for the installation instructions for that model alternator. It should tell you where the generator light should be connected. There may be other terminals such as remote sense that may need to be connected somewhere (usually the output terminal if you are not going to use it).
Excellent reply !!!!

But whatever....I reckon you are first going to have to figure out just what connections your new alternator requires. As different alternators - some are two wire - some are one wire. - have different wiring connections. Did it come with wiring instruction ? Or can you ask from the supplier ? Or at least - as we have asked before - can you post a pic of the back of the alternator ?
 

tvmaster

True Classic
Excellent reply !!!!

But whatever....I reckon you are first going to have to figure out just what connections your new alternator requires. As different alternators - some are two wire - some are one wire. - have different wiring connections. Did it come with wiring instruction ? Or can you ask from the supplier ? Or at least - as we have asked before - can you post a pic of the back of the alternator ?
Mine appears to be a two-wire. I'll post a pic when I get up under there. Mr. Old Fiat guy has been racing X1/9's for twenty years, so if anyone would know how to wire a simple alternator, geez, I hope it would be him :) I'm almost certain it's an equipment failure
 
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tvmaster

True Classic
Some pics. Installed in late August. First the low charge levels, then the ‘G’ light failure. Car starts and drives well.

9C16033F-BED1-42A6-B939-74E76CF8AA6A.jpeg
924AEDD3-08C5-490B-BA4E-B4E699D008FC.jpeg

EDC54A53-6176-4F9C-BE77-D85CEAC7105C.jpeg
F14F901B-7A35-4D6B-91AF-A5AB04AF9526.jpeg
 

Dan Sarandrea (Phila)

Waitin' On Parts...
Some pics. Installed in late August. First the low charge levels, then the ‘G’ light failure. Car starts and drives well.

View attachment 53736 View attachment 53737
View attachment 53738 View attachment 53739
God only knows what's under that taped-up lump!

Seems to be set up the same as a late model car with a Bosch alt.

The heavy wire of course feeds juice back to the battery and electrical system in general--the other end of the heavy wire should be at the starter and join up with the battery cable that runs from the pos batt post thru the tunnel back to power the starter.

The smaller wire goes to one side of the charging warning/indicator bulb. The other side of the bulb connects to the ignition switch run terminal.

When both sides of the bulb have electricity, there is no flow, so the bulb is not lit. This is what should happen when the alt is charging the system.

I would think you could test the integrity of the light circuit by:
1. Unplug the smaller wire going to the alt from its terminal on the alt (don't let it touch anything)
2. Clip the pos lead of multimeter to the smaller wire
3. Clip the neg lead of multimeter to ground
4. Set the dial to volts
5. Key in run
6. I would think the charging light should light up and the meter should report around 12v
7. If it does then the charging warning bulb and circuit are fine, telling you that maybe the alt is bad
 

ng_randolph

Bjorn H
I would think you could test the integrity of the light circuit by:
1. Unplug the smaller wire going to the alt from its terminal on the alt (don't let it touch anything)
2. Clip the pos lead of multimeter to the smaller wire
3. Clip the neg lead of multimeter to ground
4. Set the dial to volts
5. Key in run
6. I would think the charging light should light up and the meter should report around 12v
7. If it does then the charging warning bulb and circuit are fine, telling you that maybe the alt is bad
With a digital multimeter, this will not light up the bulb; a digital multimeter will not provide a meaningful path to ground in this setup. The meter should read battery voltage, though.

An easier test is to unplug from the alternator the BRN/WHT (unless it is PRP/WHT, hard to tell from the photo) wire with the red connector. Then, with the ignition on (but engine not running), ground the red connector (touch the metal part of it to a convenient ground spot, like one of the screws holding the alternator together). This should get the "G" light to light up, but in this case the bulb will probably stay dark. And if that's the case, the next job to find the break in the BRN/WHT (PRP/WHT?) wire. Start at the red connector. Often the copper wire breaks right where it exits the connector, but you won't see it because the insulation is still intact. Unwrap the electrical tape and work your way back until you find a break. I'd love to see photos of what's under the tape.
 
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tvmaster

True Classic
God only knows what's under that taped-up lump!

Seems to be set up the same as a late model car with a Bosch alt.

The heavy wire of course feeds juice back to the battery and electrical system in general--the other end of the heavy wire should be at the starter and join up with the battery cable that runs from the pos batt post thru the tunnel back to power the starter.

The smaller wire goes to one side of the charging warning/indicator bulb. The other side of the bulb connects to the ignition switch run terminal.

When both sides of the bulb have electricity, there is no flow, so the bulb is not lit. This is what should happen when the alt is charging the system.

I would think you could test the integrity of the light circuit by:
1. Unplug the smaller wire going to the alt from its terminal on the alt (don't let it touch anything)
2. Clip the pos lead of multimeter to the smaller wire
3. Clip the neg lead of multimeter to ground
4. Set the dial to volts
5. Key in run
6. I would think the charging light should light up and the meter should report around 12v
7. If it does then the charging warning bulb and circuit are fine, telling you that maybe the alt is bad
“1. Unplug the smaller wire going to the alt from its terminal on the alt (don't let it touch anything)”

What if it DID touch something, then you blow up the internal voltage regulator for example?
 

Jefco

High Mileage
My guess is that the tape lump is the original connector for the regulator, with the new wiring spliced in, to keep it as original as possible.
 

Dan Sarandrea (Phila)

Waitin' On Parts...
“1. Unplug the smaller wire going to the alt from its terminal on the alt (don't let it touch anything)”

What if it DID touch something, then you blow up the internal voltage regulator for example?
If everything is correct, nothing should happen, because at that point in the list I made up, there should be no electricity in that circuit.

If it were to touch ground for example after the key is in run, theoretically it should simply light the charging light.
With a digital multimeter, this will not light up the bulb; a digital multimeter will not provide a meaningful path to ground in this setup. The meter should read battery voltage, though.

An easier test is to unplug from the alternator the BRN/WHT (unless it is PRP/WHT, hard to tell from the photo) wire with the red connector. Then, with the ignition on (but engine not running), ground the red connector (touch the metal part of it to a convenient ground spot, like one of the screws holding the alternator together). This should get the "G" light to light up, but in this case the bulb will probably stay dark. And if that's the case, the next job to find the break in the BRN/WHT (PRP/WHT?) wire. Start at the red connector. Often the copper wire breaks right where it exits the connector, but you won't see it because the insulation is still intact. Unwrap the electrical tape and work your way back until you find a break. I'd love to see photos of what's under the tape.
"...With a digital multimeter, this will not light up the bulb; a digital multimeter will not provide a meaningful path to ground in this setup. "

A quirk of digital multimeters? Would an analog multimeter pass thru enough juice to light the lamp?
 
An ideal voltmeter would not pass any current. The reason why digital voltmeters pass less current than an analog one is not because they are digital. It is because they have buffer amplifiers at the input. If you want to pass current through the light, set it to amps, assuming it has a high enough current range. Personally, I would just put 12V across it to see if it lights. Just make sure you don't put the ammeter across 12V and ground or it will blow the meter or the meter fuse if it has one.
 

ng_randolph

Bjorn H
If everything is correct, nothing should happen, because at that point in the list I made up, there should be no electricity in that circuit.

If it were to touch ground for example after the key is in run, theoretically it should simply light the charging light.

"...With a digital multimeter, this will not light up the bulb; a digital multimeter will not provide a meaningful path to ground in this setup. "

A quirk of digital multimeters? Would an analog multimeter pass thru enough juice to light the lamp?
A decent analog multimeter would have an internal resistance of at least 10 kOhms/ V. Set to a 50V range to measure a car battery, that would be half a mega-ohm, which would be too much to light up the bulb. Perhaps a really cheap analog meter might have low enough internal resistance to light up a very small bulb, but when measuring voltage, an ideal meter would not draw any current at all. And digital meters are close to ideal in this regard.
 

tvmaster

True Classic
Starting at the start. Charged the battery up to 12.75 volts. Disconnected terminals. Will check number in the morning. Let’s see if there’s a parasitic draw, or if the battery can’t hold a charge, and then go from there.
 

ng_randolph

Bjorn H
Starting at the start. Charged the battery up to 12.75 volts. Disconnected terminals. Will check number in the morning. Let’s see if there’s a parasitic draw, or if the battery can’t hold a charge, and then go from there.
You have already proven quite conclusively that the alternator is not delivering current like it should. You really should focus on that first. As several people have suggested, find out why the "G" light is not lighting up. Most likely a break in the wire somewhere between the light bulb in the cluster and the "D+" terminal on the alternator, and probably close to the alternator end.

Once you get system charging, you can take the battery to a shop and have it tested.
 
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tvmaster

True Classic
You have already proven quite conclusively that the alternator is not delivering current like it should. You really should focus on that first. As several people have suggested, find out why the "G" light is not lighting up. Most likely a break in the wire somewhere between the light bulb in the cluster and the "D+" terminal on the alternator, and probably close to the alternator end.

Once you get system charging, you can take the battery to a shop and have it tested.
Yup, I’ll get there :)
 

tvmaster

True Classic
An ideal voltmeter would not pass any current. The reason why digital voltmeters pass less current than an analog one is not because they are digital. It is because they have buffer amplifiers at the input. If you want to pass current through the light, set it to amps, assuming it has a high enough current range. Personally, I would just put 12V across it to see if it lights. Just make sure you don't put the ammeter across 12V and ground or it will blow the meter or the meter fuse if it has one.
Sorry, how do you “put 12v across it”?
 
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