QuestionQUESTION: My 1967 mgb with a generator is not charging. I cannot get the voltmeter near since it goes crazy. I have checked my wiring connections to the GEN and VR. The brown wires from the Starter solenoid to the VR are live all the time. Do I have some wiring incorrect? Help
ANSWER: Hi Mike,
What you say about the wiring so far is correct, there should be a large brown wire going to the regulator that is hot all the time.
First thing you need is a good voltmeter. Voltmeters don't "go crazy" when they get near 12 volts.
Connect your voltmeter to the hot post on the remote starter solenoid and read battery voltage. 12v + , then have someone start the car while you watch the voltmeter. It should not drop below 9v. Set the idle at a fast idle (1000 to 1500 RPM) and read the voltmeter. It should read 13.8 to 14.5 volts. If it does not and still reads 12v. shut it down.
Make up a test lead of 10ga wire with either a large spade connector or an alligator clip on one end. (the test lead needs to reach from the generator to the starter solenoid. Add a short jumper wire to the alligator clip (14ga wire) with either a flat spade connector or another alligator clip on it.
Remove the two wires from the back of the generator and connect your test lead to the generator.(large wire to the large spade and small wire to the smaller spade)
Have someone start the car and you watch the voltmeter while you touch your test lead to the hot post of the starter solenoid. Have the helper raise the RPM from idle to about 1200 RPM and read the voltmeter. (ONLY DO THIS FOR A FEW SECONDS) You should see 15v or more.
If you see 15v, the generator is good. This means either the regulator or the wiring or the battery is at fault. If you don't get a good voltage reading then the generator is at fault. (There is no good test of a regulator with a bad generator so you will still need to do some of the tests again if you replace a bad generator.)
Let me know.
Howard
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QUESTION: Thanks Howard I have tried some of this before. My Generator is rebuilt which I am told is OK. My static test on the hot side of the solenoid shows 12.5V. Once I start the car the voltmeter digital goes crazy. I have tried 2 voltmeters. It seems there is a new field created. I do not have a red ignition dash light but the white wire from the ignition is hot when I turn the key. The jumper wire you suggest, does it jumper the "D" & "F" ong the GEN and also back to the HOT on the solenoid? The solenoid is new.
ANSWER: Mike, I learned early working in dealerships to test everything in a system, even new parts and especially rebuilt parts. And triple test any item that anyone told me is OK.
If your digital meter does not have an option to "even out" or "average out" the voltage, you need to go to radio shack or a place like that and buy a cheep analog meter. They will automatically average out the readings.
Yes, the test lead does jumper "F" to "D" on the gen and you are NOT testing the new solenoid, you are powering up the generator direct AFTER the engine is running to "Full Field" the generator. The only reason you use the solenoid connection to get power is so you don't need a 10 foot test lead to get to the battery.
This bypasses the regulator and forces the generator to do all it can do. (1200 to 1500 RPM and full fielded should produce 15v +) Don't do it for more than a couple of seconds or you will start melting things!!!! This is a standard test for all DC generators. Lucas hot wires the field and Bosch grounds the field to full field.
Let me know,
Howard
---------- FOLLOW-UP ----------
QUESTION: I have checked the battery and hot lead to the solenoid @ 12.5v. My voltmeter is OK on another car but will not read on the 67 mgb. All other electrical components work. I think that wiring to or from the VR may be the problem but I have not found anything. The VR (is new) points do not close so I think this may be the the issue. What triggers the first set to close? How do I test this? Thank you
AnswerMike, a CHARGING generator activates and operates a regulator. THERE ARE NO TESTS YOU CAN MAKE OF A REGULATOR UNTIL YOU TEST THE GENERATOR. The standard test of a generator is to FULL FIELD the generator and bypass the regulator, as I have indicated.
The only other thing you can do is test the wiring to the regulator. F,A,D & E are indicated on the regulator.
"F" is the (field) wire on the generator,(small wire) "A" is the hot wire. "D" is the large wire on the generator (Dynamo) and "E" is the ground (Earth)
Lucas often used two "A"s but will always use the F,A,D & E letters.
The points in the regulator will never close if the generator is not charging. Or the wiring is not connected.
