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Discussion Starter · #1 ·
Hi guys - here's the problem.
I was attempting to start a fresh rebuild. Starter wasn't turning. While checking for voltage, I noticed the wire harness that runs along firewall was warm and so was the matting bulkhead connector. Discovered that I had swithed the R and S wires on the starter. Swapped them and the car started. Now the GEN light stays on, which it didn't before. I'm guessing the switched starter wires may have caused this. Checked continuity of the wires in the harness on the firewall side only, and they are good.

I have replaced the (external) volt reg, the ignition switch and had the alt. tested by two shops - OK. Battery is also new.
While researching in this forun, I found an alt/V.R. test by Peter F. Here are the results: VDC

terminal KOEO KOER
F 5.4 6.6
2 4.8 8.4
3 12 16.8
4 5.4 6.9

Readings at the blue, white and red at the back of the alt where the same as above F, 2 and 3. While running, at the GEN bulb, I get 12VDC at the pink and 7 - brown.

Any help would be appreciated. Thanks
 

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Here's Peter's input again.
From the above (KOEO = key on engine off and KOER = key on engine running).
F terminal - KOEO = #4 slight voltage KOER = 9-12V typically
#2 terminal - KOEO = 0V KOER = >3.2V
#3 terminal - KOEO = 12V KOER = 12V
#4 terminal - KOEO = F slight voltage KOER = 12V

The alternator isn't being regulated. You have a large voltage on terminal #2 when the car isn't running. There should be 0 volts. Try unplugging the connector on the alternator with the key off. Measure the terminal in both the alternator and plug for terminal #2 (relay terminal). See if that 4.8 volts is coming from the alternator or the plug. It should not be there.
 

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Discussion Starter · #3 ·
with the key off and the alt connector unplugged I'm getting:

connector blue = .7 VDC
connector white = .9

alt blue (marked "F") terminal = 0
alt white (marked "R")terminal = 11.4

the following are readings with the key on engine off and alt connector unplugged:

connector blue = 11.25
connector white = 7.65

alt blue (marked "F") terminal = 0
alt white (marked "R") terminal = 11.4

volt reg:
F = 11.25
2 = 7.65
3 = 12
4 = 11.25

I know this is more info than you asked for, but I thought it may help. Thanks
 

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Is the regulator grounded? I assume it is still mounted on rubber wellnuts. The regulator should have a ground strap to the core support. You should also have a wire from battery (-) to the right inside fender.
Regulator doesn't seem to be working right and the wires between the regulator and alternator don't look open or mixed up. That is, the wires look OK.
 

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Discussion Starter · #5 ·
The regulator is mounted with the rubber wellnuts and it does have a ground strap to the core support. There is no wire however from battery negative to the right fender, but I did check continuity from battery negative terminal to voltage regulator body, and there's continuity between the two. The battery is grounded to the right front of engine block via large cable.
 

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Originally posted by Marks66396:
The regulator is mounted with the rubber wellnuts and it does have a ground strap to the core support. There is no wire however from battery negative to the right fender, but I did check continuity from battery negative terminal to voltage regulator body, and there's continuity between the two. The battery is grounded to the right front of engine block via large cable.
Not saying it's the problem, but continuity does mean everything is ok. You're measuring back thru the engine to firewall, if you have those straps installed or thru the drivetrain/exhaust. It may meter ok but not be able to handle any current. You really need a good solid connection from the body to the battery negstive.
 

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Still looks like a regulator problem. That 16.8 volt reading you got shows the alternator can deliver.
 

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I believe the "R" wire was there for ignition enrichment voltage during the starting operation for OE ignition setups. What sort of ignition are you running? If you have an MSD or similar unit or an HEI or both, you don't need it. Also I had to install a diode on one of my VR wires when I installed my Crane HI-6 ignition to make the GEN light work correctly and prevent run-on.

Don't know if any of this helps but thought I would throw it out there in case you have a similar situation.

Troy.
 

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Discussion Starter · #9 ·
Makes sense about grounding the body directly to battery via fender. The fenders are off the car right now (getting ready for some Marina Blue paint). As I said, the fender wasn't grounded before, but it will be when I put the front end back together.

I think I will try another regulator, John. I believe I remeber reading one of your posts that mentioned the Wells reg. (VR710?) Is that the best reg. to go with?

I did swap out the original points for an HEI. I left the "R" wire running to the new distributor. I thought it wouldn't hurt to have that full 12 volts during cranking.

Speaking of cranking - last night I blew out my second NAPA starter with the freshly built 396. I'm just under 11:1 compression. Car hasn't been on the street yet, so the engine is still tight. I don't know if I've got a problem or if the NAPA starter can't handle high compression. Have you guys ever tried one of those high torque mini starters they sell in Jegs and Summit for around $200?

appreciate all the input
 

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Don't know about those but I never use anyting but a GM HD starter on Chevys. Rebuilts and after market brands never work out for me. My local "independent" garage does the same thing. They on use GM heavy duty starters on Chevys too. Too many come-backs otherwise.
 

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Couple of things. As Finally mentioned, you don't have the regulator grounded. Swing the ground strap that you took off the fender and tie it to the radiator core support. Then test things again.
It was a Wells VR715 from Auto Zone for around $11.00. Disconnect the battery before installing and that unit also must be solidly grounded.
It's OK to have the yellow wire to the HEI BAT terminal. I hope you aren't using the original resistor wire though. The HEI doesn't like that and needs a non-resitor wire to operate.
 

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Discussion Starter · #12 ·
Once I get the starter replaced, I'll try grounding the core support and retest. If I still get the crazy readings, I'll replace the reg. with a VR715. I'll update the post to let you know how things went.
Yes, I replaced the resistor wire.
 
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