Greeting.. I have a 1999 VDP 4.0 ltr. Got it out of a persons back yard. Did some simple repairs and it was running fine. Now I have a Light that says: Battery not charging. So I looked into the forum and found some good information. Replaced the tensioners and put on a new belt. I checked that battery while the unit was not running. It came out to 14.6 volts plus. So then I went and checked it with the engine running... 15.7volts. Next I stressed tested it and found that the voltage was not as good as it was suppose to be, radio cut out. So I was going to replace the alternator. However, now I see the Gearbox error light on. Also the Shifter is locked up and will not come out of park. And to top all that off the ABS light just popped up.

I have to start wondering if this is not so much the alternator as somthing else. I do have a bad plug and coil that I was going to replace. The code shows it is miss firing....
Im at a bit of a stopping point.. I really do not know what to do next.. or If I should just bit the bullet and put it into the shop... Any and all suggestions for this issue would be appreciated.

 

You have a faulty regulator inside the alternator. With it over 15 volts running you possibly damaged other electrical components. Have yours rebuilt! Do not drive till voltage running is 14.2 or at least above 13 volts.

 

If it's in the shop have them send it out to be repaired.

 

+1 on the voltage regulator.

 

There is something wrong with the battery voltage reading of 14.6 volts when the alternator is not running, should be about 12.6 volts. If 14.6 volts is not a typing error, I would check with another multimeter.

 

If his regulator is putting out too much, he will get an overcharge reading (if done shortly after shutdown) until the cells deplete and cannot accept that voltage anymore (for which a new battery is needed). The battery will swell also, maybe not the whole unit, but the dieing cells...probably should remove the battery and get it checked. But you are correct MS, it should be around 12.6-13.2 depending on when it was metered after shutdown and a second multi-meter should be used to verify.

Something else to check would be the Mega Fuses (spare tire well), ...with the voltage stated, I'm surprised one hasn't burned out or could be the reason for the faulty voltage reading. They are cheap, I'd replace them anyway.

 

You are quite right about checking the large fuses, in particular for loose or corroded terminals. I recently had a problem with my lights fluctuating (noticed it looking at the interior lights) when the engine was running. Put the multimeter on the battery and could see that the alternator voltage was, at random, fluctuating between 13.5 and almost 15 volts. Knowing that my alternator was good (just rebuilt with new rectifier, regulator and brushes), I unbolted all connections at the large fuses, cleaned them thoroughly and tightened back again. The alternator voltage fluctuation immediately stopped and has not re-appeared over the last 6 months.

If the contacts are somewhat poor at the large fuses, the alternator voltage will fluctuate (or go too high) because the alternator's voltage regulator will sense reduced voltage because it is sensing it far from the battery - from fuse #2 (5A) in the engine compartment fuse box. Poor contacts at the large fuses will cause voltage drop further downstream which will give the alternator a false signal that the voltage is too low and the voltage regulator will push the alternator voltage higher to compensate and go above the normal maximum of some 14.2 volts. Checking the contacts of the fuse #2 will also be a good idea.