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Discussion Starter · #1 ·
My '68 is exhibiting erratic voltage levels from the recently installed triple guage set. These measurements are validated when measuring directly at the battery with my multi-tester.

The dash light burns at start-up as it should, then it's quiet. However, at the guage the voltage hovers around 12V at warm idle and shoots to ~16V above idle. Some dip occurs while signals are applied or when accessories are active.

The alternator and regulator had been replaced prior to my acquisition and appear relatively new. However, the #3 wire (fusible link) from the regulator seems 'worn' and softened, not like the other three wires at the connector. Here are some questions:

1. Should my alternator have a ground wire lead from the rear terminal? If so, it's not there. What should it be grounded to? My manuals don't show/specify this connection.

2. My regulator has a capacitor connected at the side. It appears to be original (OLD!). What role does this play in the charging system? Again, my manuals don't show nor discuss this component!

I expect that this condition had been present and gone undetected, until my guages were installed. Please assist, I'm prepared to offer additional information as needed. Thanks.

------------------
Brian Scott
1968 el Camino Custom
307-PG Purchased 11/01 w/81k (2 CA owner)miles.
"An eBay success story!" The build sheet search continues...

[This message has been edited by madaboutabba (edited 11-02-2002).]
 

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"My '68 is exhibiting erratic voltage levels from the recently installed triple guage set. These
measurements are validated when measuring directly at the battery with my multi-tester."

Suspect that the condition existed before adding the gages. It just wasn't visible. Adding the gages didn't create the problem

"The dash light burns at start-up as it should, then it's quiet. However, at the guage the voltage hovers around 12V at warm idle and shoots to ~16V above idle. Some dip occurs while signals are applied or when accessories are active."

The GEN light sounds like its behaving normally. I assume that the 12 to 16 volt reading is on the internal volt gage you added. The reading is fluctuating and way too high.

"The alternator and regulator had been replaced prior to my acquisition and appear relatively new. However, the #3 wire (fusible link) from the regulator seems 'worn' and softened, not like the other three wires at the connector. Here are some questions:"

Worn and softened aren't a concern. That's a covering over the fusible link. If it doesn't have tears or has been burnt, I won't worry about it.

1. Should my alternator have a ground wire lead from the rear terminal? If so, it's not there. What should it be grounded to? My manuals don't show/specify this connection.

No, not needed. Gets a ground through its frame and the mounting bolts.

2. My regulator has a capacitor connected at the side. It appears to be original (OLD!). What role does this play in the charging system? Again, my manuals don't show nor discuss this component!

Little, unless it shorts, a rare condition. It's purpose is noise, spike reduction, EMI, much the same as the capacitor (condensor) across the points. Has a purpose but doesn't make things run.

"I expect that this condition had been present and gone undetected, until my guages were installed."

You got it, problem has been there.

"Please assist, I'm prepared to offer additional information as needed. Thanks."

What's going on is the alternator is working but it's not staying in regulation. It should remain around 14 volts but using your gage readings its falling down to 12 volts and probably going about 16 volts. The alternator is not being regulated.
1, Check the leads between the alternator and regulator. No open wires?
2, The regulator needs to be grounded. I believe the 68 mounts on 3 rubber feet (wellnuts). If so, it needs a ground strap to the core support (frame). Maybe someone threw this away.
3, Double check the voltage off the back of the alternator large red wire both at idle and maybe around 2000 rpm. This will get some better readings

Problem is with the regulator area. Check out those things and post back.
 

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Discussion Starter · #3 ·
Thanks, John. Your method of response is very direct and professional and your assistance is much appreciated, too. I'll be back tomorrow.

Brian
 

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Discussion Starter · #4 ·
OK-

I've not located any 'open' wires between regulator and alternator, all appears well. I measured voltage at alternator (only at cold idle ~1100 rpm) which agrees with remote triple guage and multi-tester battery measurements. So...is the alternator output (my measurement of ~15.5V) a result of the regulator's function, or is this measurement independent of the regulator operation? If so, does this indicate that the regulator is ineffective (being 'bypassed')?

Additionally, the regulator is installed directly to the steel fender/core support. The manuals specify to install so that the rubber grommets/cushions are not defeated in their functions. While my regulator is not cushioned, it is certainly grounded. Comments to this effect?

The cheapo replacement regulator is readily available and cost about $11. Should it be pre-fitted with rubber 'feet'? I plan to pick one up after work tomorrow, unless your advice instructs something else. And you said to not sweat replacing the condenser?

Thanks again,
Brian
 

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When you say #3 wire are you talking about the wire going to terminal #3 on the regulator? That wire should always be at battery voltage so that's an easy way to check it.

Just because it's bolted directly to the rad support doesn't mean it is actually grounded. Check from the regulator base to the battery -ve for any voltage. Shouldn't get any there.

Search for posts by me related to charging. I've posted a good description of the charging circuit and operation a few times before.

Peter
 

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Peter is usually right but I guess I missed the reference about terminal #3. Don't see a mention of it.
If you try and replace the regulator, pick up a Wells part number VR715. Autozone carries these solid state units. Yes, it's supposed to be grounded to the core support. Disconnect the battery before installing it.
 

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Discussion Starter · #7 ·
Ok, the new Wells regulator solved nothing. The unit is non-adjustable (better for me!) and seems to no longer incorporate the cushioned mounting points, so I still have a good ground. After observing for about 30 seconds of idle, I re-installed the original unit. I'll have the alt bench tested this weekend. Any comments/direction until then?

The new regulator's packing insert/directions stated that the alt should give at least a 2.5 ohms measurement between the alt's F terminal and ground. Is this a correct statement? I grounded at various points but could only manage a trace value, >.5 ohms.

I see that Peter F (and others) does have various posts which I'll try to scan as time permits.

Thanks,
Brian
 
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