Bizarre alternator and starting issue

[pyroman]

First off, I've got the 3G alternator. I took the car for a spin yesterday after honing in on the timing better. The car fired right up and ran well. Only complaint I had was that the battery was draining. This morning I discovered my alternator wasn't charging. After a little more investigation I found that I had not hooked up the "I" terminal trigger wire. I went ahead and ran 1 wire from the "I" terminal to the green w/ red stripe wire that feeds into the voltage regulator connector just to see if there was a difference.

Got in the car, started it, and immediately got loud belt squeel which to me told me that the alternator was charging. I went inside and came back out to try it again and this time left it running. Once it started I tried playing with the throttle and it immediately sputtered and died. I thought this was odd considering how smoothly it has been running.

It got weirder from here. I went back in to try and get it started again but it just kept turning over and never fired up like it had so easily before. I go again to try and start it, turn the key and I get nothing. It won't turn over although all my electrics are working. I also noticed my anmeter gauge was doing wacky things. Like if I put the key into the "ON" or "ACCY" position the needle would sort of throb, moving back and forth. I thought maybe the battery was undercharged so I slapped on the charger and went back in for awhile.

Came back out about an hour later, took off the charger, hooked up the battery and went to try and fire it up again. It fired up pretty easily this time again and was accompanied by belt squeel which went away after a few seconds. However, the idle was at about 2000 RPM. The previous day it was idling right around 800-1000. After a few minutes the idle started to get rough and I had to keep revving it in order to keep it running. Eventually it died. I went to start it again and nothing, it wouldn't turn over. I checked the voltage across the battery and it was in the range of 11.7 volts.

Now, I know that is undercharged, however the voltage across the battery has been lower but it would still crank even it if was slow cranking. In this case it was either cranking strong or not cranking at all. That is why I don't think the battery is the problem.

The only thing I can think of it is that I potentially damaged my starter solenoid. I do have a alot of wires on the positive side. I'm still confused as to how my ignition system after it ran so well yesterday they seem to be separate isolated systems.

Please help, thanks.

 

[pyroman]

On second thought, do the 3G alternators need to be externally grounded? I figured they were internally grounded but maybe not? If so could that be the root of the problem?

 

[Tim65GT]

What is the voltage output when running?

I don't think a stock ammeter will be very acurate with the 3G higher amps. The amp gauge "current loop" may also cause you issues if you are still using the stock harness.

There should be about a 560 ohm resistor in-line with the green/red wire to simulate the gen lamp.

I don't think the high idle issue is related to the electrical.

You are right about the 11.7 volts - it should still crank. If you can get it to crank by using jumper cables across the solenoid, then it probably fried from all the cranking.

I'm not sure about the internally grounding, but I ran a short 2 ga ground cable on mine.

edit:

I forgot, you do have a 2 ga cable going from the alternator output to the solenoid, right?

 

[golf4283]

With my 3g install I had to bypass the ammeter cause it can't handle the 3G. Try just taking out the gauge cluster really quick and taking the wires off the ammeter and splicing them together. Be very careful though as the wires are battery 12v hot.

 

[pyroman]

What is the voltage output when running?

I don't know right now. I know it wasn't charging because I just unhooked the positive post on the battery to see if it would stay running. It died immediately. This was before I hooked up the trigger wire. I wasn't able to measure the voltage or unhook the battery once I hooked up the trigger wire because I couldn't keep the car running long enough. I did notice that the starter seemed to be laboring less when I was cranking it after I hooked up the trigger wire.

I don't think a stock ammeter will be very acurate with the 3G higher amps. The amp gauge "current loop" may also cause you issues if you are still using the stock harness.

There should be about a 560 ohm resistor in-line with the green/red wire to simulate the gen lamp.

I do have it connected to the stock harness. I connected it to wire 904 running off the voltage regulator connector in the following diagram. That right? I take it the resistor is closer to the ammeter.

http://www.hammar.dyndns.org/wiring/1967/67ignit1.jpg

I don't think the high idle issue is related to the electrical.

High idle and then hard starting. That to me is the weirdest problem. The electronic ignition is so nice because it just fires right up. As soon as I hooked up that trigger wire it started acting weird.

You are right about the 11.7 volts - it should still crank. If you can get it to crank by using jumper cables across the solenoid, then it probably fried from all the cranking.I'm not sure about the internally grounding, but I ran a short 2 ga ground cable on mine.

Yea I tried that and it did crank. But after leaving it sit for awhile the car would crank by the key. If I tried too many times to crank it I'd get nothing. Almost like the starter solenoid was overheating. As far as the grounding goes I haven't grounded mine, maybe I'll give that a shot and see if it makes a difference.


edit:

I forgot, you do have a 2 ga cable going from the
alternator output to the solenoid, right?

I don't have a 2 gauge wire but I do have a 4 gauge cable runing from the alternator, to a 175A fuse and then to the starter solenoid.

 

[Tim65GT]

Here is a diagram for 3G conversion.

The LtGrn/Red wire normally gets ignition voltage through the Alternator Warning Lamp. Since you have an Amp gage your system doesn't have one, so a 560 ohm resistor can be placed in-line to simulate the resistance of the bulb. It can be located any where in the path, so where you hooked up to the voltage regulator connector is good.

When the alternator is not charging, It has a ground potential on this line to light up the lamp. Without the bulb or resistor to drop the voltage, It could be bringing the voltage to the electronic ignition down low enough so where it doesn't fire.

As golf4283 said, it might be a good idea to bypass the Ammeter at least until you get your charging issue figured out. You simply tie the wires together. You could move one to the other post so they are both fastened to one post on the back. Once you get everything worked out and you could put it back and if it starts acting up again, you know something was jacked up with the gauge.

It sounds like your solenoid is not fried, but on it's way. There is a lot of current going through it when cranking, so yes, it will get hot after a while an eventually burn out. Luckily they are not that expensive.

Sorry, 4 gauge cable (not 2 ga), That is fine for the alternator output.

 

[pyroman]

I was looking at resistors but there are so many different 560 Ohm resistors I don't know which to get. What sort of power rating should they have?

Thanks.