MG MGB and MGB GT Tech Talk
Hello, I would like to test my electrical system while my engine is currently out of the car. Is there a easy/safe way to do this? How do I complete the circuit with the engine out and starter disconnected?
Thank you.
Bolt together all the wires with loops that were bolted to the starter solenoid, that will complete the circuit.
Ok, there are like 4 wires.. Two where together and bolted to the solenoid battery terminal. The other two cliped onto the solenoid. If I remember correctly.
There should be two (my car has three but it's a 79) with loops and two with spade connectors, one large, one small, the large one is the one that trips the solenoid, the smaller one supplies 12v to the coil while the starter is cranking.
Just bolt the two with the loops together. The one thing I don't know about is the alternator, I don't know what not having that plugged in would do to the circuit, you may have to plug it in.
Thank you. Yeah, does not work. I am assuming the alternator may need to be in play as well.
Well I plugged the alternator in and it is still a no go. So I tried connecting the two wires with loops together and then running a line directly to the negative terminal and got nothing.
You did switch the ignition on when you plugged everything together did you?
Then I will confess to being stumped, however there are plenty of electrical experts on here, somebody will come up with an answer.
Jeremy
Do you have a volt-ohm meter?
Check the voltage and polarity and try connecting the positive post through the meter to ground ANYWHERE other than the other battery post. Do you get current?
If not, you either have a dead battery or a bad ground.
Yeah, but the meter is at work... I will have to bring it home tomorrow.. I'm fairly certain the battery is fine. It's got a full charge on it, and I have a trickle charge on it.
Is it possible I have the poles reversed on battery? If I connect a line to the positive terminal on the battery and connect to any bare metal on the body, (all over), I get a light on my battery tester. And if I connect that same line to the two wires that go to the starter I also get a light on my tester. This happens whether the ignition is on or off.
Jeremy, if you have a negative ground system then the following should occur
+ post to ground - light goes on
+post to wires that connect to the starter [not the small wires but the ones with the big connecting rings] - no light. you have no completed circuit.
Ok, well I have both, postive post to ground, test light on. Positive post to starter wires, light goes on.
That sounds like you have a short or a bad main cable. In fact that is a fire waiting to happen and I am baffled how your battery is holding a charge.
Disconnect the cable from the battery and use a continuity tester (Volt-ohm meter set to ohms) to see from BOTH ENDS, one at a time, if you have current flowing from the chassis/body to either end of that cable.
If you do, replace it. Somewhere there is a short circuit.
So it is not possible that the battery is reversed? I mean is the chassis mounted cable supposed to be connected to the negative terminal or the positive?
Thanx again.
Ok, I found my problem.. One of them anyway... I connected/looped the two cables that go to the starter, but not the positive battery terminal.
Now I get something... but I think it is still a short of some kind. I am back to the clicking noises I had when the starter was attached.
I wonder if the voltage regulator is the source of the clicking.
The negative battery cable should be connected to the chasis.
Look at the wiring diagram for your car. http://www.advanceautowire.com click on stock schematics. Make yourself a couple of enlarged copies, one for reference, and one to make notes on as you check the wiring.
To bypass the starter:
All the brown wires and the positive battery cable that were connected to the starter should be connected together and insulated so they don't touch the chasis and short. The white/brown wire that goes to the solenoid should not be connected to anything and insulated so it doesn't short against the chasis.
Make sure any other disconnected wires are insulated from the chasis (example would be wires going to the distributor, the alternator, etc.).
Using your copy of the wiring diagram, take a methodical approach to inspecting and testing all the wiring, connections, and components. Fix each problem as you come accross it. Clean each connection and use dielectric grease to prevent future corrosion.
Replacement bullet connectors, terminals, sleeve connectors, and wire are available from Victoria British, Moss Motors, British Wiring.
Dan Masters has provided online instructions for replacing bullet connectors on his site.
http://www.advanceautowire.com click on instruction manuals and then click headlight relay kit.
Ok, I found the source of the clicking and the short. It was the horn. So far so good.. Thank you to everyone who helped!