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Several Electrical Questions

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M

mxp01

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Gentlemen:

Related to my 1960 BE:

- How many amps should be the two fuses be?

- I dropped the fuel tank and installed a new fuel sender. With about 1 quart of gas in the tank the fuel gauge read full. Bad gauge?

- The electrical system has been acting very sporadically in the past week. We think we have a bad ignition switch. With the ignition on we don't get any power to half the fuse box. The headlights don't work, the blinkers quit working, and the fuel pump won't turn on, among other things. If the ignition is bad, can it be repaired? Or, is replacement the only option.

Any input is appreciated.

Mike Pennell
 
20 amp will work fine.
 
The fuel gauge can be corrected by grounding the sensor most likely. Indicating full when virtually empty should mean there is too much resistance in the circuit. I wouldn't condemn the gauge till last. If necessary, you can pull the sender and gauge and check them together with a 12v power supply. Easiest is to drop the tank and extend the sender wires to reach the tank on the ground. You will have to ground the tank if you do this with a jumper wire. Grounds are often culprits of many of the electrical problems with these machines.
JC
 
This is the time for a wiring diagram and a voltmeter, or at least a test lamp. You need to find the points where you are losing power. To do this, you measure the voltage between the wire connection points and ground. Start at the battery, continue out through the various circuits as you see them on the wiring diagram. Eventually you'll find the point where the voltage changes from 12V to zero. Simply jiggling the wires to a connection will tell you a lot about whether it is erratic.

The Bugeye has one electrical branch that is switched and fused, a second that is not switched but is fused (which goes only to the horns, for some incomprehensible reason), and finally the lights--all the lights except the turn signals--which is not fused at all.

The problem may or may not be the ignition/light switch. There are plenty of places where things can look connected but really are not. All the power goes through the regulator terminals, for example, and the screw connections are notoriously unreliable. The "bullet" connections in the harness can also get loose. Even if a connection seems tight, corrosion can render it erratic.

Be systematic in checking these things and you'll find the problem, I'm sure.

By the way, you might want to check the info in the Wiki under "General Technical Articles" about the difference between British and US fuses. The fuses are 35A by the British designation but the closest US equivalent is 20A. This is OK even if you have extra electrical equipment like a fuel pump, as long as it isn't high-power stuff.
 
When we dropped the fuel tank I removed the existing sender and replaced it with a new sender. There was a single wire from the sender that then headed into the trunk just below the license plate. I did not see where it grounded at that point. The tank was held in place by six bolts that should provide some type of ground, at least for the tank.

Is there some way to test the old sender without hooking it to the fuel gauge? I think Kim says it should conduct very little power at near empty and more as the tank fills.

Any suggestions?

MXP
 
Ground is through thise six screws and the bolts that hold the tank on.
 
This may be a silly question, but when you replaced the sending unit... you did buy one for an early car and not a later one didn't you? The BE will have a sender that operates between about 10 Ohms when empty and 80-90 Ohms when full. Later senders have a wider resistance range and operate in the opposite direction (240 Ohms = empty, 30 Ohms = full).
 
- I purchased the correct sender for the type of vehicle.

- The tank was held in place with two pieces of material on each side that had two bolts. I concluded this material was there to reduce noise and vibration. The other two bolts do not have this same type of material in place. When I replaced the tank I put this material back in place. The other two bolts have nothing between them and the body. Does this sound like sufficient ground?
 
I'm not sure about the integrity of that ground connection. With the bolt-on sending units I've heard of people making an additional ground wire with a ring terminal and securing that in place under one of the sender's flange mounting screws. If the sender is too hard to access at this point, how about making a small bracket of some type that will allow you to connect a new ground wire between the flanged edge of the tank and the car's chassis?
 
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