Hey all,

Ive been mucking around with my external voltage regulator (carb swap, so no PCM to control the field on my 92) and I’ve noticed my volt gauge (aftermarket) bounces around at basically any rpm. Idling it bounces a little bit, and at specific rpm’s it goes crazy (12-18 volts). My stock gauge doesn’t move, but my led clearance lights kinda brighten and dim in the same frequency as the needle moves, same with my dome lights and my headlights it’s just less noticeable.

I have a Carquest Regulator RAA1049 from an early gen Dakota I believe, as well as a new carquest 136 amp alternator for a Durango.

Ive followed all the steps for the regulator setup. The regulator is triggered by a relay that is triggered by ignition (this is a dedicated relay, the only thing it does is trigger the regulator), the body of the regulator is grounded to the alternator case, I have a 4g charge cable and a 4g engine ground to the battery. I might get a 8-10 gauge wire and run it directly from the alternator to the battery, but not sure if that would help much as I figure my ground isn’t fully the issue. Unless it is, maybe I’m wrong.

If I put a volt meter onto the battery it reads pretty stable, so I’m stumped. Any ideas?

 

The pos and Neg wires should be the same size. On my 94 Dak, stock alternator, I have a # 4 gage to the fusable (Green) link, then to the Batt + and -, well, I don't like hooking extra wires to the Batt posts. The wire runs down the top of the valve cover and around the firewall to the battery. I have a power distribution plate and posts that hook between the Batt + and the rest of the System. Yes, I insulated from the metal fender. I picked up the insulated binding posts from Amazon. They're 1/2 in or 12mm posts. 3/8ths or 5/16ths would have worked also.

Since I have those leaks in the hood, I have to clean those connections a lot. I'm trying a rubber flap diverter.

After checking to make sure every connection is good. Both + & - ? Careful about making a ground(Grd) loop, it's basically different potentials between any connections, both + & -. Except in the pos. Is it a positive loop? I was getting different voltage readings at separate spots in the vehicle.

Regarding the gauge, it's not bouncing from a rough ride, had to ask, I'll say NO, probably just drifting? From 12-18volt? Could it be the gauge? Because the VOM reads stable. Or does it read 18v also? Are the other symptoms of a drifting charging system, the lights get brighter and then dimmer? The heater fan can speed up and slow down. When you throttle up the engine, does everything work better than at idle? The alternator is putting out more umph at a higher speed. Unless the alternator is designed specifically to give more power at a certain speed, when you change its speed, it will change its output.
Like an A/C GenSet, I increased its speed, and it increased the Frequency; it went from 60 cps to 75 cps. Bad things can happen then.
If you switch something on, does the gauge show a lot of movement? Checked against the VOM.

I had a 1977 Honda Civic, a straight 1200cc, the federal smog stuff. I put a catalytic converter on it, and it failed the smog test. Couldn't pass the visual. I upgraded all the wires to a larger size. The alternator would switch on, then off, continuously. The headlights were flickering all of the time.

Tell me what you think.
It's like my discussion about power spikes; someone, somewhere, asked me about them, and I was mainly asking others what they thought. Maybe I'm just digging to china about it, my PCM still works, and I have dual electric fans.

 

It bounces too quickly for me to hear the heater fan changing speeds, but my LED clearance lights flicker and I can see them, as do my gauges and my dome light. Headlights do too but it’s not as obvious. VOM stays steady at 14-15 depending on what the truck is doing, but the gauge bounces from 13-15 at idle (smooth idle as well, so it’s not the engine bouncing). At certain rpm the needle jumps from 10-18 oscillating violently then it goes back to a small wiggle around 14. The engine ground and the alternator feed wire are the same gauge as well, although it’s hooked to the PS mounting bolt, so I ordered a cheap 4 gauge wire to connect to the alternator case directly to see if that helps anything as a test.

 

Have you tried a different regulator?

 

I’ve tried 4 lol

 

There should be a rectifier bridge somewhere, I suspect it's in the alternator, and it isn't working properly. Alternator puts out A/C current, rectifier changes that to D/C current...... and I don't think its doing its job properly.

 

I forgot to mention that I just bought the Durango alternator to replace the alternator I previously had in the truck. Both alternators did the same thing

 

Were the regulators all from the same manufacturer??

 

One was from SMP, and 3 were from carquest

 

It would be interesting to see what voltages you were getting from the alt..... see if it is indeed putting out a/c current.