So like the title says my alternator isn't charging. I'm showing 12.2v at idle. I've swapped the relay and got no change. I checked that I'm getting a signal from the PCM to the alt and it was not. My AC is still working correctly so that rules out the CPS. Im guessing after tracing the wires that the PCM controls the alt relay by opening and closing the ground. I grounded the relay and got power on the two small lugs at the alternator but still only show 12.2v at the battery and charger lug on the alternator.

The parts store tested the Alt and say it's good.

I bought the transpro internal regulator for the alternator but before I try that I wanted to see if anyone had any other ideas on where I should look.

Any ideas??

 

Usually the first thing to fail in the PCM is the regulator. Many have installed an external regulator, me included. If the CPS fails, it will not close the auto shutdown relay causing the alternator to go full output. You can rewire the relay directly onto the ignition switch and stop any future alternator over volt problem.

 

I'm not having an over charge issue, I'm having a no charge issue. I'm not sure if I'm understanding the working correctly either. Does the PCM operate the relay by completing the ground?

 

My mistake, yes the PCM ground the auto shut down relay. So just run that wire to ground instead. The regulator also controls through ground via the PCM. It goes ignition feed, relay, alternator, PCM regulator, to ground. You need to bypass the PCM part. Easy, just cut the wire that goes back to the PCM and run it to your external regulator, the other wire takes power from the relay. https://www.dieseltruckresource.com/...-101-a-307266/

 

In the wiring harness that runs across the top of the firewall, find the dark green wire and the dark green with orange stripe wire. It is the dark green wire you want to cut. Stow the end that runs back to the PCM. The end that goes to the alternator connect to your regulator. Tap into (don't cut) the dark green with orange strip for power (or sense) for your regulator.

Cut the dark blue with yellow stripe wire near the auto shut down relay and connect the relay end to ground. Stow the other end.

 

I bought the transpro internal regulator to put into my alternator. Would I just install it and then ground the relay like pictured above?

 

Any problems I've had with the alternator that wasn't the alternator itself proved to be wire harness problems. One was a broken wire going to the ASD relay. Another was a connector problem between the alternator and the PCM.

 

Internal regulator and grounding out the ASD seems to have fixed the issue.

J_martin, I had tested and traced all the corresponding wires as best I knew how. That is how I arrived at the fact that the PCM was not grounding out the ASD as designed.

 

I guess I spoke to soon. Now I'm getting an intermittent check engine light.

 

With paper and pen in hand, turn your ignition switch on - off - on - off - on. Count the flashes which will be in pairs of groups. 55 is end of the list.

 

This is why I love older vehicles. No computer, no problem.

 

There's pros and cons to the computer. Modern engines with computer supervised mix, timing, and often even acceleration live a whole lot longer than their grandpas. Part of it is more precise manufacturing, but a great deal of it is that the cylinders are not washed with liquid gasoline at every cold start. (the choke routine). The precise supervision also helps, as the engine is run at peak timing without pre-ignition, so it doesn't suffer from either knock damage or overheated exhaust from late timing damage.

Back in the 60's, getting 100,000 out of an engine was cause for bragging and celebration. Now 200,000 - 400,000 is met with a yawn. That's on consumer engines. Our CTD's are actually industrial engines.

If all the parameters required to meet emissions were manually programmed and hard wired, it'd be a nightmare to diagnose. The computer can usually tell you which component is failing, or at least the parameter (mix, etc) that is out of spec.

 

Those emissions regulations are now being used to effectively outlaw diesels.
https://ericpetersautos.com/2017/06/...jihad-expands/

 

I don't want to bring the VW mess and cancer over to this forum, but, the point about VW cheating wasn't that they could not meet the standards, it was that they did not want to pay Mercedes Benz 350 dollars per unit to license their ADblue urea system. It was pure and simple greed, nothing more, nothing less. The "no bad news" attitude of VW management and pure avarice brought on their self inflicted foot wound. I like diesels, but I don't like greedy corporations more, they got what they deserved and I got a new 2017 4Runner. Thanks VW ...Mark Edit: Some light reading:

http://forums.tdiclub.com/showthread.php?t=448053

 

It will be Saturday/Sunday before I can look at it again. I'm in Alabama now on vacation. I realized shortly before I left that I had installed the internal regulator incorrectly. I need to fix that and see where I'm at.