I have a 09 f350, deleted and tuned with a spartan.

A few months ago I was driving along, alternator died on me. Had the puff of smoke come out of it and drained the batteries.

I changed the alternator to a non oem one, checked batteries, everything was fine, no battery light, charged fine, no codes.

Fast forward to the past few weeks. Driving along, the stereo shuts off, abs light comes on (no battery light comes on) alternator doesnt charge. Drive for about ten minutes and it kicks back on. This happened while I was traveling so I just kept on going. Stereo shut off again, abs light came on again, bout ten minutes later everything was good again. Get to our destination, park overnight, truck batteries are dead the next morning.

Ok so i charge them up, drive the truck, stereo and abs light deal happens again. (still no battery light)

So we drive home, I pull the alternator, take it back to where I bought it, they test it, it shows its putting out 14v, so I take it home and reinstall. I take apart all connections and clean everything.

Drive my little girl to school, and the abs light comes on and stereo shuts down again. On the way home though, the dash lights die, the battery light does come on this time, and im about 10 miles away from home, so i pin it and try and get home. Truck starts to buck a little and the pedal is "sticking" (due to low battery), then all of a sudden, radio kicks on, dash lights come back on, everything is good!

I get home and park, and the batteries were just about dead.

So, I take the batteries out and get them tested, this time they show needing to be replaced. Im taking them back for warranty tomorrow.

In the mean time, I have taken and tested the 150 amp fusible link (continuity test and tested to ground to see if it was shorting) and it tests good, and ive tested a few other wires that I can get to, and so far everything is testing good. No blown fuses or relays in either of the fuse boxes.

I keep charging my batteries on a smart charger, and last time when i started the truck, I had my meter hooked up to the batteries, and it wasnt showing it was charging. I also cycled through the dash menu, and it said the charging system was OK (heh yeah).

So the alternator tested good, batteries show that they should be replaced (show 750cca on load test and the batteries are 850cca) truck says charging system is ok, no blown fuses or relays(unless i missed a hidden one somewhere?) 150 amp fusible link tests ok.

SO what am I missing? Where do I need to check next? The guy at the repair shop said to maybe check some wires going to the starter? (never had an issue with the starter not working yet)

Is there any other wires I could be testing, or could I check the output of the alternator myself while I have the truck running, right down at the alternator? Should I be resetting the tune on my spartan, or looking into some kind of computer issue?
Would my weak batteries cause an issue like this where the alternator wouldnt show that it was charging?

I keep thinking about how everything worked perfect before my alternator died, and worked fine for a few months, and now this issue, and I can piece together what may have happened.

Any advice or direction greatly appreciated.

 

Check the wires on the alternator. I think one wire is commanded from the engine management to be 'on" - that might be what you are experiencing.

 

OK thanks, are you referring to the plug, that has three wires? (I think its three)

If so, then it should read 12v, when the engine is running? Or can i test it not running, or...?

 

Have you checked with your meter to see if the batteries are being drained by a parasitic draw? Have you installed anything new in the way of new stereo, or trailer brake or remote starter or a security system on the truck? Any new electrical connections?

The way your batteries are being drained constantly makes me think you either have a parasitic draw drain them down over night or that something is glitched in the charging system. I would crawl under the truck and make sure the wires on the starter all good and everything is tight and you have no corrosion

 

Nothing new in regards to installation, besides the new alternator.

The batteries dont actually drain while the truck sits overnight. I have tested that by testing the battery voltage in the evening, then again the next day. It didnt change so i didnt look into the parasitic draw at all. I could check that for sure, but from everything ive experienced so far, it really seems like the issue only show up while running/driving.

 

how are you testing the alternator for proper funtion

I dont see anything about you load testing batteries ....how old are they...yes..charging shorted batteries with new alternators will result in 0 cranking power.

 

Testing the alternator I test for output at the batteries. Meter set on 20v dc, one prong to each terminal. Then look at the reading from before I start the truck, to after, and the meter reads the same, does not jump up to 14.X as is should.

Batteries were tested, as in load tested, at the local napa. They read borderline good, so I had them replaced under warranty yesterday, no change in symptoms.

As well I took the plug off of the alternator, and tested when the truck was running, and the outside red wire reads 12.5v, the outside purple wire reads 11.2v,(this wire reads 0 when not running) and the center blue and red wire reads nothing. In another forum, a fella told me to test the duty cycle of that plug, but I dont know how to do that and havent done that yet.

 

If you havent added anything new and you just picked up two new batteries for the truck and all your connections are good, my suspicion is that the alternator is not up to snuff.

If the batteries are fully charged I would disconnect the alternator over night and when you get up in the morning go out to the truck leaving the alternator unplugged and see what you battery voltage is. It could be the alternator even though testing good isnt up to snuff.

It could be that one battery isnt up to snuff and is pulling the other down with it and then of course not enough go go juice to turn the truck over. Something is drawing them down, it's just a matter of figuring out what it is. I guess we should have asked, but when did this issue start occurring with your truck?

 

Yes the batteries are new as of 3 days ago and good. I have left them hooked up over night, tested the voltage, an then tested again the next morning, and there is no voltage change. This weekend I tested the wires from the alternator to the pcm, and they both tested good. So, all my connections are good as far as continuity. Everything is clean, very clean now as well haha.

The starting issue was tied to the charging issue. It started right after the intermittent charging problems. What was likely happening there was my batteries were on the verge of being no good (according to the place where I bought them from and got them replaced under warranty on friday) and the intermittent charging issue just wasnt keeping them up to par.

So the issue I have is still the charging issue.

To recap, batteries are new, wiring is clean and tests good, when I had the alternator tested, it tested good, fuses and relays are good.

Now my guess the whole time has been that the alternator (which is just a few months old) has something screwy with it. I am going to get it re tested again.

The only other thing thats left is the pcm, unless Im missing something else?

 

Lets hope it isnt the PCM that wouldn't be a light touch on the wallet. Hopefully some of the FTE members will see your thread and chime in with some different ideas what could be the cause for you to have a look at. Never a fun time when your chasing down something like this.

 

It's your alt.

Did you never say in your probe that you checked the ground wire to the Alt????

You can get voltage all day on that positive scale, but check the ground wire to the alt.

If indeed it tested good. Your getting the right input, but not the right output.

DVM on continuity would be my main mission at this point.

Denny

 

The only wires that go to this alternator, are the large gauge red wire to the battery, then there is a plug with three wires in it, two from the pcm, and one from 12v source. I dont think there is a specific ground wire to them, is there?

 

update. My issue ended up being the alternator was intermittently working. I did test pretty much everything I could in the charging system and it was all good, so I took it back to where I got it from and got it exchanged, and installed it, and its all working properly. Which is odd, cause they did test it, and they said it was putting out the proper voltage. Something was intermittently wrong with it, and its all good... for now! Thanks for all the help.

 

Glad to see you found it. Lots of people get fooled thinking the alternator is all good, wouldn't be the first time the alternator is the culprit after being rules out by the guys selling them because they tested it. Now you can go places without worrying about being stuck somewhere with dead batteries..

 

Yeah, for now! The first alternator lasted just over 2 months. It came with 2 years of warranty, and I hope im not stuck swapping it out every few months.

But I have a feeling I just may be doing that haha.

Lets just hope it was a flukey one.