How to check Voltage Regulator

76sealingwaxred · Posted: Wed Feb 04, 2015 8:53 pm Post subject: How to check Voltage Regulator

Just got my 1971 running after sitting in storage for 10 years. Ran great , but after running for a while it seems to me like it is running rich. Before I start messing with things, I checked the charging system at the battery. At idle I am getting just about 13 volts(12.8-12.9). When running about 2000 rpm I am getting 13.5-13.6 volts which I have learned is too low for the this type of FI system and could be the source of the "rich Condition". The brushes are good and I have cleaned the contact areas. I suspect the Voltage Regulator. How do I test and dio this system instead of just throwing parts at the system? Also read, if it is the VR I should use the Bosch unit 30-019. Please point me in the right direction.

Thanks
Jim

Danwvw · Posted: Wed Feb 04, 2015 9:48 pm Post subject:

Ok so I take it we are talking about a car with the original 12 generator not an alternator. Yes the Bosch Solid state regulator is the way to go. 13.5 to 14 volts sounds about right for one though. Change the brushes and dress the commutator too. Commutator-Cleaner, Brushes. Also if the car has been setting quite a while it's going to need all the battery cables and ground connections cleaned and greased. Probably a new battery would be good. Don't get an oversized battery for a generator.
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1960 Beetle And 1679cc DP W-100 & Dual Zeniths!

Donnie strickland · Posted: Thu Feb 05, 2015 4:03 am Post subject:

Test your generator first:
http://www.speedyjim.net/htm/gen.htm

If your generator is good, and you are absolutely sure all your connections are clean and tight, and your battery is good (load-test it first), then you can replace the regulator.
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71 Elm Green FI A/T Squareback

Bobnotch · Posted: Thu Feb 05, 2015 8:08 am Post subject:

76sealingwaxred · Posted: Fri Feb 06, 2015 7:19 pm Post subject:

Tried test generator. Took off both leads going to generator. Then attached jumper wire from DF to a rear bumper ground. I then but the ohm meter lead on the D+ lead. I get no readings. What did I do wrong. I did all these tests with the car running. I also noticed the DF lead would spark when I attached my jumper wire that was leading to a body ground? Also cleaned battery ground and trans ground and some others. I suspect my VR. I can't get this system to charging consistenly. Sometimes I did see some low 14 volt range but just for a moment. Mostly charging at 13.5-13.7 range a 2000 plus rpm. I also noticed that when it was charging higher the car seemed to idle smoother? Does this make sense? I know these FI systems like the 14 plus charging voltages. The car is a 1971 SB.

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Bobnotch · Posted: Fri Feb 06, 2015 9:59 pm Post subject:

Donnie strickland · Posted: Sat Feb 07, 2015 6:55 am Post subject:

The test says "Connect a jumper from DF on the generator to the generator frame."

Sounds like you grounded DF to the car, and then grounded D+ to the car as well. Ground DF to the generator body itself and see what you get.
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71 Elm Green FI A/T Squareback

76sealingwaxred · Posted: Mon Feb 09, 2015 1:15 pm Post subject:

Ok, so I properly checked the generator. At idle in was putting out 27-29 volts. When idled up to 2000 rpm volts measure 41-47. Do these numbers sound like normal generator output?

Thanks
Jim

Donnie strickland · Posted: Mon Feb 09, 2015 5:59 pm Post subject:

That sounds all right. The exact number isn't that important; but you know it's putting out plenty of voltage. If all connections are good I'd suspect the regulator at this point.
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71 Elm Green FI A/T Squareback

76sealingwaxred · Posted: Tue Feb 10, 2015 7:51 pm Post subject:

Still trying to get 14.0 plus volts out of my charging system. Today I replaced the generator brushes that were quite worn and at the same time replace the voltage regulator. The regulator and brushes were Bosch units. Although I did get the made in Mexico version of the regulator. Needless to say, I still am at 13.90 volts at 2000 plus rpm? Can't get into the 14 plus range that this FI system likes. Whats my next step?

Bobnotch · Posted: Tue Feb 10, 2015 9:28 pm Post subject:


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