Alternator not charging?

[collins_dan]

Had a long and frustrating ride home last night in the S4. It died while driving home. If I got a good jump, it could go about a 1/2 mile before needing to be jumped again. (It's good to have other friends with old cars willing to act as support vehicles.) I put a new alternator in a couple of weeks ago and it must not be charging the battery, but the strange thing is the light on the tach never came on, and I don't recall if it came on when I started the car. Here are the checks that I have planned, let me know if I'm missing anything. 1) Check that battery is holding a charge. 2) Check that fan belt is not slipping. 3) Check the indicator bulb is not burned out. 4) Check that large gauge wire from alternator is charging battery. I understand that this would normally go from the alternator to the regulator/control box to the solenoid to the battery. I checked the connection at the control box, it is fine, but I have no solenoid (electronic ignition). I'm wondering what the path to the battery would likely be in this case? Let me know if I've missed anything and any thoughts for how to check the complete path from alternator to battery. Thanks. Dan

[john.p.clegg]

Dan

Step 1
With your ignition on,the thin wire at the alternator when disconnected should test 12volts,and if you earth it the "ignition" light should come on...this is the excitement feed for your alternator...

John

[Frank Howard]

I put a new alternator in a couple of weeks ago...

Check that large gauge wire from alternator is charging battery. I understand that this would normally go from the alternator to the regulator/control box to the solenoid to the battery.

I checked the connection at the control box, it is fine, but I have no solenoid (electronic ignition)

Dan,

I suspect you didn't wire your alternator correctly.

[rcraven]

And if you didn't wire it properly and connect the battery to it you may now have damaged it.

[collins_dan]

I'm trying to figure out how the last 2 comments are helping me to solve this problem. I believe I wired it correctly. It's not complicated wiring. Just 2 wires coming off, exactly like the old generator. It came with instructions that I followed correctly and all the connections seem tight. Rather than just tell me that I've done something wrong, please help me to determine what's wrong. Thanks in advance. Dan

[Carlos A]

I do not know if this will help but something similar happened to me 6 months ago. I checked everything and nothing seemed out of the ordinary (except the fact that the alternator was not charging). I turned the car on and asked my son to move /wiggle the alternator connections a little with a long piece of wood (a wooden stick). I noticed an intermittent change in the ammeter (gauge). It turned out that the connections to the alternator were lose, and vibration, some oil, and a lot of heat made things even worse. It took me a while but the problem is now solved (new good quality?not Chinese--connectors and a heat shield).

Best

Carlos A

[collins_dan]

Carlos, Thanks. I'll double the connection more thoroughly. This is going to seem stupid, but how do I check that the alternator is charging? Connect the positive of my multimeter to the alternator battery output and the negative to any ground location? Am I checking for voltage or amperage? Thanks. Dan

[neilsjuke]

Volts 14 to 15 of them at 3000 rpm
Neil

[Frank Howard]

Dan,

When you say "Check that large gauge wire from alternator is charging battery. I understand that this would normally go from the alternator to the regulator/control box to the solenoid to the battery", it makes me think you could have wired it incorrectly. When you say "I have no solenoid (electronic ignition)", it makes me think you could have wired it incorrectly.

Initially, you laid out 4 items you planned on checking. Some of the things you said (which I quoted) indicated to me that you wired it incorrectly and that is what you needed to check. You can check those 4 items until you are blue in the face, but if you wired it incorrectly it will never perform correctly even if all 4 of the items you plan to check appear to be OK.

It's like saying you hooked all of your plumbing fixtures in your house but you're not getting anything but natural gas out of them. Then you say you're planning on checking all of the fixtures to see if they are working properly. While you're checking the four items you mentioned, you could also check the operation of your heater valve and your seat adjuster, but regardless as to whether or not those things are working properly, checking them is not going to help you fix your problem. You can check the faucets and the toilets and you'll find them to be working properly but until you disconnect the water line from the gas line and connect it to the water line (wire them properly), no water will be coming from them.

While I didn't explain that the plumbing must be disconnected from the gas line and connected to the water line, I did recommend that you not waste your time checking the faucets and toilet and instead concentrate on the way the plumbing is hooked up. Recommending that you divert your attention away from the fixtures and focus on the way your system is hooked up is my way of helping you to solve your problem.

[Galwaylotus]

The alternator needs the ignition/charging light working to provide excitation to the alternator. If it isn't there, the alternator won't charge. Check to make sure the lamp is wired in and that the bulb hasn't failed.

[collins_dan]

Frank,
I've attached a copy of how the alternator is wired. I have an S4, so had the RB340 control box, which I have eliminated and replaced with a terminal block, but the connections are the same. One is used to connect the light gauge wire to the warning light. The other connects everything that was previously on the B terminal, same as orginally.

When I said that it would normally go to the control box then to the solenoid then to the battery. The part that is unclear to me is not the control box connection, as that is correct per the attached instructions. It is the fact that I have a solenoid, so how does the connection go from the control box/terminal block to the battery?

If I have my terminology wrong, please let me know what I am saying incorrectly. I'm not doing it to be annoying, I'm just not very knowledgeable about this stuff. But learning more everyday thanks to this site!

Thanks. Dan

[Frank Howard]

The part that is unclear to me is...the fact that I have a solenoid, so how does the connection go from the control box/terminal block to the battery?

Dan,

You confused me because you also said, "I have no solenoid (electronic ignition)" Do you have a solenoid or don't you?

If you do, the solenoid has two large posts. One of these posts has a heavy lead going to the battery (let's call this terminal A) and if you have the original Lucas starter, the other one has a heavy lead going to the starter (let's call this terminal B). If you connect the wire from the control box to terminal A, you are connecting it to the battery.

Further, the solenoid is not eliminated when one installs electronic ignition.

[john122S]

In the US, a trip to the local auto supply store will find a cheap 2" ammeter for about 10 USD that can be temporarily wired between alternator output and battery hot wire (in the case of my +2S these connect at the main terminal on the remote starter solenoid). Multimeters usually read only a few hundred mA and not the 50A that an alternator could produce.
Cheers, John in Indy

[collins_dan]

Frank, I apologize. I just mis-typed. I was correct the first time. I have no solenoid, because I have a gear reduction starter, which I know understand means that the solenoid is incorporated into the starter. Sorry for red herring about the electronic ignition. Now onto figuring out how the wiring works without a solenoid. Sounds like I will need to trace from where the battery connection comes through the firewall and meets up with a brown wire somewhere, to make sure that this connection is still good. Thanks. Dan

[Carlos A]

Carlos, Thanks. I'll double the connection more thoroughly. This is going to seem stupid, but how do I check that the alternator is charging? Connect the positive of my multimeter to the alternator battery output and the negative to any ground location? Am I checking for voltage or amperage? Thanks. Dan

You have an ammeter gauge inside the car... Don't you? That gauge will tell you if the alternator is charging or not. That is why I asked my son to wiggle the connections while I remained inside the car.

If you do not have an ammeter, you can get one for few dollars at a local auto supply (as John indicated).

Best

C