Alternator failing

[Demid22]

Anyone ever seen this. Ill be driving, and randomly the battery voltage will shoot to mid 15s low 16s, all the interior electronics shut off (im guessing a safety) driving lights shut off, but engine continues running. Ive double checked my wiring. Fuses. Relays. Cant find anything wrong. I dont see any shorts. Nothing. Im guessing when it hits those high voltages it hits some sort of safety to keep from blowing everything up. Then it cleaes up and acts normal. Car will do this idling too but its random. Took alternator.off to have it tested. Shop said it was fine. Although im.curious if this is an electrical gremlin that only shows during heat cycles and load. Any ideas? TIA.

 

[Hunter]

Subbed

 

[Linda's Hell Cat]

1. Have you asked your Tuner to look at data logs?
2. I've also seen where the belt tensioner needed replaced because of belt slippage and caused a problem a problem like you are having.

 

[Demid22]

Jon says he doesnt see anything on the tune side commanding that high of voltage.

Wait...belt slip would cause higher voltage??

 

[covidcommander]

Jon says he doesnt see anything on the tune side commanding that high of voltage.

Wait...belt slip would cause higher voltage??

Don't think so, lower voltage maybe

 

[Demid22]

Don't think so, lower voltage maybe

Thats what i was thinking.

 

[Billet Train]

maybe check ground locations. Loose wire?

 

[fumanchu182]

You have a short to ground. Please check your fuel system fuse if it is a Fore aftermarket system with the FC controller. If it is stock it is a bad ground. Quick hits:

Grounding capacitors on back of heads.
Ground strap to trans/engine.
Bad battery connections or shorts.
Check wires near headers if you have headers.

 

[Linda's Hell Cat]

Jon says he doesnt see anything on the tune side commanding that high of voltage.

Wait...belt slip would cause higher voltage??

That was how someone solved their problem, said they changed their Tensioner.

Most times it seems like, it tends to be something with the battery.

Someone also had a problem because a small wire that is plugged into the battery voltage sensor wasn't tight. I guess it came loose.

 

[Unholy707]

You have a short to ground. Please check your fuel system fuse if it is a Fore aftermarket system with the FC controller. If it is stock it is a bad ground. Quick hits:

Grounding capacitors on back of heads.
Ground strap to trans/engine.
Bad battery connections or shorts.
Check wires near headers if you have headers.

And the ground to the transmission bell housing.

 

[Unholy707]

Mine is usually low (13.4-8) shoots up to 14.5 under boost and drops back down. Could be a bad intelligent battery sensor. Mine has always been low on the challenger (Durango is always steady at 14.2) but weird fluctuations since getting a new glass mat battery

 

[Unholy707]

Then again I know I have a short to ground with my passenger fuel level sensor and I have various things turned off in the BCM I’m sure there’s a few things I need to reconfigure

 

[TraxMoe]

Check your connections. Electrical arcing can cause that phenomenon and if it is connected to a coil the magnetic fields collapsing around the coil will also cause a spike in voltage.

 

[Demid22]

Check your connections. Electrical arcing can cause that phenomenon and if it is connected to a coil the magnetic fields collapsing around the coil will also cause a spike in voltage.

Ill check again but i see nothing shorting or broken. No arcing. When it happens car runs fine. Could the alternator be internally shorting?

 

[covidcommander]

Check your connections. Electrical arcing can cause that phenomenon and if it is connected to a coil the magnetic fields collapsing around the coil will also cause a spike in voltage.

Sciency

 

[Unholy707]

As mentioned in the other place, I’d start here. Wiring is in really bad shape. I’d replace both headlamp to dash and engine harnesses with NOS, can probably be found on eBay. Also, a short to ground won’t always appear as a CEL on the dash. You need to scan the BCM and possibly PCM. The car will demand the voltage it needs.

 

[Demid22]

Just couldnt help yourself huh? Lol.

Anywho, alternator was the culprit. Another member on other site having same problem, same fix. Alternator.

 

[Demid22]

New alt

 

[Linda's Hell Cat]

New alt

That's great, you have it installed and everything is back to normal!

 

[Demid22]

That's great, you have it installed and everything is back to normal!

Yes ma'am. Now to get to the track friday. Thanks Linda