Code name “Baby”

[rvpopeye]

Old vans need replacement of worn out parts just like old people . At least it happened in familiar territory .
Hope it's old enough to make the replacement easy.

[GypsyDogs]

The parts were cheap..(good name brand ones too..) but the shop fees, labor, and parts markup were not. They charge the customer 2.5-3x the actual part price …. $igh
And my local shop got bought out.. so their labor price went up $60/hr…

But she’s done now.. and I am glad she decided to do this here in town.. not a thousand miles away in bfe.. (already been through that !! No fun)

[GypsyDogs]

Dangit.. now I need to figure out how to effectively carry a bike on my van…. Found an old 1sp for sale.. and spiffed her up.
Hmmm
No hitch, so that’s out.. won’t fit inside.. (and K’ne would disown me..)

Thinking……

[GypsyDogs]

OOOO - FUN-  not

Getting charge spikes at running speeds..  idle is fine 13.7-14.3, but when going down the road.. she can spike from 13.8-15v for split seconds..  

Something is amiss.....   

Just a couple years ago- changed alternator and pcm...    sigh





god, I hate chasing wire issues..

[GotSmart]

Voltage regulator?

[GypsyDogs]

That was my first thought.. but
Just recently replaced both alternator and pcm.. (facepalm)
So either end of that function should be good… but- might not.

I am going to start with pulling and sparklifying battery connections and any ground in the engine I can find. And the pcm controller connection on the alternator (it might have picked up grunge during the last flooding of streets)

Also the levels of the spiking seem to be somewhat rpm dependant..
Thankfully, they only last for split seconds.. they don’t persist..

[rvpopeye]

Interesting intermittent .
Just a thought but worth a try and costs very little except time. When looking into the power + grounds , don't just look. Take them all apart and make 'em shiny. Especially any braided ones. Maybe even add some ?
Also try disconnecting all power ,remove and touch the battery cables together for a little while (20 seconds or so) to make sure you drain all capacitors in it's tiny little brain and then let it sit for a few minutes before powering it back on.
Check the power connections to that battery meter or whatever is showing you the spikes too.

I'm sending good ju ju karma for luck.

[GotSmart]

Voltage regulator?

[rvpopeye]

John is saying alternator is because the voltage reg is sometimes built into the alternator (and I wouldn't be surprised that on newer models it's just a part of the software??) ....New parts don't guarantee it's actually in perfect working condition these days , rebuild places are not all created equal. Get a parts place to test it if you can. Might have a warranty on it ?
And about the spikes . The battery will probably just ignore them but a vehicle computer might not be so forgiving.Then again , a computer glitch might be the culprit ?

Double checking wiring terminations is unfortunately an ongoing maint. item on old vehicles so still do that .

And for anyone wondering . Post repeats after doing an edit are noted , the posts before an edit have been /will be deleted . (Software glitch example arrrrgh)
Anyone seeing any other post doubles , please let me know .

[sternwake]

The voltage regulator is Internal to the Engine computer on Dodge Since '88

The Alternator is Externally regulated.

There is No separate unit even though the parts books will gladly tell you there is one.

A actual giant voltage spike would indicate that either the VR is fully fielding the alternator briefly, when the battery is already fully charged, and thus cannot accept much amperage, or the battery is losing connection with the alternator charging circuit, and the alternator current has no where to go.
The battery is basically a big filter and shock absorber.

You are not going to change its voltage super quickly, but if the battery is losing connectivcity with the charging circuit and the voltmeter is connected to that charging ciircuit rather than directly to the battery, you will see spikes when the battery is removed. Same reason why the old remove a battery cable from a running engine to check to see if the alternator is functioning is a super bad idea for any vehicle made within the last 35 years.

Another possibility is voltmeter error or Electro magnetic or radio frequency interference screwing with the voltmeter's sense wire, and If your phone happens to be near the voltmeter, try moving it away.

I'd Suspect the voltmeter first, but definitely double check the battery connections and make sure the alternator body is electrically grounded to engine and frame, and the two smaller connections on it are clean and tight.

The two connections on the back of the alternator, one goes directly to engine computer, the other picks up system voltage. theone going to the engine computer is basically PWM grounding the Field connection, to maintain the voltage.

My voltage regulation on my '89 was a YoYo of 13.7 to 14.9v with unexplained spikes occurring for no particular reason I could ever determine.

I got so irritated as the engine computer Voltage regulator Insanity I added an modified external regulator so I could choose the voltage setpoints manually

. In order to do so You need to add a 50+ watt 10 Ohm resistor between the two wires which attach to the alternator now to trick the engine computer into thinking it is still connected to the alternator.If you do not add the resistor the check engine light will come on and certain parameters of running the engine will go 'open loop' and power and MPG will suffer.

Consider the possibility that the engine computer's voltage regulator is just doing its insanity thing, and that insane is normal for it.

if the voltmeter is a new addition then i'd say ignorance is bliss, and carry on.