Bluegrass is correct, the PCM has ZERO involvement with this era charging system. You would be wasting hundreds of dollars if you replace a PCM for this issue.

The alternator already has SIX diodes internally that do just that, however, they are not in the regulator circuit.

If pulling F11 relieved the drain condition, then the regulator is the most likely cause.

 

Thanks again guys for all the help. I ordered a regulator and will let you know how that goes? I am still puzzled by 3 new alternators/regulators with bad regulators in them but that's the only thing I see also. I will post again in a few days.

 

what exactly happens after the 45 minute sleep mode .......?

 

That delay is in the GEM module, controlling power to certain accessories. It has nothing to do with the alternator.

 

OK, so your saying , after the 45 minutes the GEM puts things into sleep mode and if you STILL have power loss, then the only thing left ( or most obvious) is the alternator.

 

No, you still have to do your troubleshooting in case the GEM didn't power down.

One can, however, check for a drain from the alternator without waiting for the GEM to time out, you'll just have to compensate for that additional draw from the GEM's circuits and ignore it.

 

To isolate the alternator drain (using your posted wiring diagram), with the ignition in the OFF position, remove fuse #11 and in its place put your fused ammeter and see if there is any current flow.

 

That is how I figured out it was the #11 fuse. I put the ammeter between the positive post of the battery and the battery cable itself. I can watch the GEM time out and the current draw drop to .010 after 30-40 min or so. It is .050 until then but that is done with e #11 fuse out. If I leave it in (#11 fuse) I get erratic current draws from 1 - 3.5 amps or so. I can see the GEM time out with the alternator current flows but it stays .70 - 2.5 +-. I have been taking the fuse out the last couple of days and have not had a minutes trouble with it. If I leave it in it will be dead in the morning. Voltage regulator will be here tomorrow (A good one). Lets hope that solves the problem? Thanks again!!

 

As previously mentioned, requiring them to be tested before purchase is basic due diligence. However, it is not the end-all, be-all "this part is awesome" test. In the case of my mom's 00 Neon, she purchased an alternator from Autozone and had it tested in store. It passed on their machine, but failed the in-car voltage test. Plus, it was an annoying PITA to access due to it being near the firewall and requiring a carefully positioned mirror to even see what you're doing.

This might seem kind of dumb, but have you checked the Mega fuse block for corrosion or damage? When I tried to clean then connections, my original one broke in half as the hardware was rusted together. Made a temporary replacement that worked for about a week, then it began displaying signs of not charging. Alt cable terminal (same location where the 20A field fuse bolts on) was HOT and kept working loose no matter how much I tightened it. Finally, it just refused to charge despite being tight. The next day, I took it apart and found the temporary base I made had melted, despite no signs of grounding out. The stud in question, made of A2 Stainless Steel had turned an odd brass color too.

Made a new fuse block that night using more suitable hardware that would hold much more firmly in the base and added locknuts to every connection. I gave each piece of hardware some air space around them to help dissipate heat as well. After cleaning each junction down to bare shiny metal, I bolted it in, fired it up and the truck was instantly back to normal.

Something I would like to mention is that I suspect the original studs had never been touched before. The Alternator fuse & cable came off together and had to be chiseled apart.

 

257BEE,
This is a good thread that illustrates the need to understand the system, do the checks for pinpointing the probable trouble area, then the repair needed.
To many are looking for an easy fix, looking for the answer from some one else and/or cannot understand what they are to do or how.
Unless the issue jumps up and bites, an in depth check is mandatory or have some one else that knows, do the work.
I can assure most that you will not be able to do these repairs on later year truck or cars because they are twice as complex so you need to know and have tools to use.
Just take a look at the forums for the later years and see the ridiculesness that goes on.
Especially about the charging systems that are computer controlled now.
And Techs are supposed to go to school on these systems yet but the owner is bound to try it himself. It's called 'no clue'..
Good luck, you did good with a learning curve add in..

 

Well the new regulator arrived so I pulled the alternator back off and changed them out. I put everything back together, started the truck, checked the alternator output voltage (14.2V) and then drove around the block. I then disconnected the battery and put my ammeter back in between and right at 220 ma or so. I opened the door and seen the light draw, closed it and watched the draw go down after the lights went out (back to 220ma). Went and sprayed round up to kill 30-40 min, came back and I was down to 10ma with NO erratic draws taking place at any time. I put the battery post back on and now I am keeping and eye on the battery voltage and it has been steady for a couple of hours so no draw as of right now. This is something that has not happened over the last few weeks, I was guaranteed a voltage drop over a couple of hours unless I pulled the fuse or unplugged the alternator so I think the problem is solved. I have learned a good bit on this one. The first thing I learned was not to second guess my troubleshooting just because I bought a new Orielly's alternator (and a 2nd one) and it had what I thought would be, a new trouble free voltage regulator on it. I studied the diagram and tried to find a different problem because I just knew the voltage regulator could not be it? Looking back the diagram is a fairly simple one and after testing the plugs and the wires themselves I should have followed my first thoughts. I think the testing done on these alternators new and refurbished will have a hard time finding the faulty/leaky regulator. I think they look for a tolerable output voltage then in the box they go. I hope this thread helps someone else down the road and I appreciate all the help along the way.

 

I have seen this many times before.
The rebuilders do not do a quality job.
The stores do not do testing to the level it should be done, and only with the equipment they are given to work with and the level the employees is at..
The idea is to make a buck the fast way on volume and not be concerned with those who fall through the cracks like yourself.
Rebuilding is done on a contract basis so the cheapest company gets the job.
This thread should be a good lesson that shows there is more to it than just simple thinking.
Today most everyone looks for access to the answers and to that end has no clue to how anything works so they can help themselves.
Not much learning happens when the solution is supplied by some one else.
Thank you for sticking in and running it down.
Knowing how the system works, just kept pointing back to the regulator.
Good luck.