Engine/Transmission (1998.5 - 2002) Strange alternator indication

[rootmanslim]

Driving along, cruise set a 65 and all of a sudden I hear "ding, ding, ding".

Since I have a fuel pressure gauge on the column I had to look over it to see a readout i have never seen in almost 90K miles. "Check gauges" HUH?

Start with OP, no issue, fuel no issue, coolant no issue, voltmeter uh oh says about 8 volts. thought the OEM fan belt had finally died, but no, intact.



Shut her down and checked the two brand new batteries to see if there was something loose..... nope.



Turned on key, indicated 8 volts, started up and right up to normal voltage indicated. Drove home 50 miles with no issues. Have driven it every day since, indicates 8 or so until started and then up to normal.



There was no check engine light or any fault left behind.



It is kept on a battery maintainer and a timed heater (cold in WY) and intake heaters never cycle unless I leave it outside for hours.



Never had an alternator crap out in 90K miles. Changed the belt just because it is 10 years old (I carry a spare).



Any thoughts or just a stray piece of crap in the alternator ?



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[SeanM]

The PCM regulates the alt volatge and does this based off the battery temp sensor underneath the drivers side batt tray and EVR circuit line voltage. So maybe the PCM glitched and cut power to the field wires or your brushes are going. I just rebuilt my alt so this is all fresh in my head still. If you have any questions let me know.

 

[SeanM]

sorry I should have asked this before I didn't see that you keep it on a batt charger, what is normal on your volt meter? Because it will still show the voltage in the batts if the alt is not working. I ran mine with a bad alt for over 2 weeks because I didn't have time to fix it. I would just put it on the trickle charger when I got home to keep the batts charged. If you have a multimeter check the batts when the truck is running. It should read somewhere between 13. 8 and 14. 2

 

[rootmanslim]

Sean the voltmeter shows 8 volts when off 13-14 when running, so no question that it is charging. the temp thing may be it as it is cold here at 7000'in NW WY. If the brushes are "going" I guess I'll wait until it happens again. It will soon be sitting for 5 months while we migrate to Key West in our Hemi AWD Magnum ( a much smoother ride). Come next June I'll see (as it only does about 6K miles/year hauling horses since we bought the Magnum in 05')
As a sidebar, dropping the Magnum and keeping that silly 300 which has less room, neither handles nor goes any better, was one of MOPARs better moves. I really wanted an AWD SRT Magnum but that was a no no. The SRT Jeep has AWD but it is sooooo ugly and built like a brick. Biggest error was NOT keeping my 12 valve..... immune to EMP!

 

[SeanM]

I suppose if you had a 12valve with a stick you would be immune to EMP lol. Any ways the temp sensor tells the pcm when the batt gets to hot so if its cold outside it shouldn't be affecting it if altenator is not overcharging.



By the way thats a nice looking truck you have. I wish mine had less then 100,000 on it. Hell I wish it had less then 200,000 on it.

 

[wlowe]

Let me know if you decide to sell that front bumper