3G installed but........

[Hemmi06]

I was unable to find the answer to the following question about the 3G alternator install. This is my first question I was unable to find an answer will all the knowledge in these forums.

Should the truck run while disconnected from the battery with a 3G alternator? Mine does not.......

I disconnect the negative post of the battery and it shuts down. It also does the same pulling the positive terminal.

I have made sure all ground straps are properly grounding as they should be: PASSED

Checked to see if the 3G is actually charging: PASSED (Multimeter shows 13.5-14V at battery running and 12.5V shutdown - I could tell the alternator was changing load based on demand)

I am really thinking it is something simple that I am forgetting. What am I missing? Any ideas will be surely appreciated....

[bluef250]

Although the engine should continue to run if the battery is disconnected, It is a bad idea to disconnect the battery when the engine is running. I would suggest that you carefully review the schematics for a 3G install.

http://www.fordification.com/forum/view ... =8&t=13062.

also, I suggest that you read the following:

http://www.bcae1.com/charging.htm

"Some people tell you that you can check your alternator by disconnecting it from the battery to see if the alternator can produce enough current to keep the engine running. BAD IDEA! Disconnecting the battery will subject the voltage regulator (and computer and audio equipment...) to significant voltage spikes which may cause an otherwise good alternator to fail. Even if there were no damaging spikes, this test would not indicate whether or not the alternator was good because the engine will easily run with a weak or failing alternator."

Electrical equipment that might be damaged on bump truck include the voltage regulator, the alternator, points or electronic igntion, switches and radio. I am probably missing something.
"Simple Test:
If you want to see if your alternator is producing current, turn on your headlights when you're parked and the engine idling with the headlights shining on a wall (at night). Notice how bright they are. Then turn the engine off. The lights should get dimmer when you turn the engine off. If the lights get brighter when you kill the engine, the alternator was not charging sufficiently. When doing this test, the lights should be the only load (turn the stereo, a/c and other accessories off). With a heavy load, an otherwise good alternator may not be able to produce sufficient amounts of current at idle."

[Hemmi06]

I do disconnect the battery while its running but do not have the time to reconnect to keep from shutting down because it shuts off instantly. So I have not had a chance to fry stuff yet.

I have followed the wiring diagram to a tee - The only wires from the original harness that are not connected are the AMP meter leads (the solid red and solid yellow wires).

The alternator does charge I have checked the voltage with a meter while running 13.5-14V at battery and 12.5V shutdown, I can tell the alternator is adjusting its workload based on the amount of items running (Lights, radio, heater fan, cigarette lighter, flashers) because the load I hear it put on the motor. I turn them off and I hear less demand from alternator.

The funny thing I believe it is something very simple and my brain has filed that little gem of knowledge too far away for recovery.

Keep the ideas flowing folks.... bluef250 thank for adding to the knowledage base of my brain!!!

[bluef250]

Did you install the resistor between alterator and the ignition switch?

[Don H]

Are you pulling the charge wire from the alternator off with the battery cable? How about are all the grounds tied to the neg. battery cable?
Don

[Hemmi06]

Bluef250: I have the resistor in line with the ingnition. There is also 12V at the green/red ignition exciter wire from the ignition.

Don H: Battery and Alt terminate at the solenoid post, all power for truck (Ignition ect...) also terminates there.

Today I have spent the whole day doing different wiring setups. One wire alt setup, with/without resistor, 12volt to both S and I terminals. They all provide a charge to battery while running but removal of the battery from the loop it will not run.

I know it is not a big deal if I have a good battery but the one time it dies (Plates short, blows up, or I drill a hole in it) I will be stranded. I believe I had experienced this in the past with a real dead battery and the tow truck could not jump it (Prior to 3G upgrade). Is it a Camper Special issue? I am leaning towards an issue with the alternator itself but I was hoping it was something different.

Thanks for the ideas Don H and Bluef250!

By the way I am a pro at removing and installing my alternator as I have done it roughly 6 times today. Anybody needing an alternator changed I will provide my professional services (wiring not included in professional services). Just pick me up and I'll do it!!

this is the guide I have used, followed to a tee:

3Ginstall.jpg

[marz68]

I just looked at mine and it's wired just like yours and i pulled the negative and positive and it stays running.
My alt is out of a 90's taurus.
Can yours be a revers rotation alternator? Maybe not if you said that there is a good charge when you check it with the volt meter.

[Hemmi06]

Thanks marz68: Something to think about I will probably leave it be until I can find the smoking gun causing this issue.

Next idea: I am leading towards changing the voltage regulator in the 3G as it was a junkyard takeoff and see if it is not accepting the 12v excitor wire signal. I will keep updates as I dig through this issue.