TheSamba.com :: View topic - 356 Electrical Problems

Fri Aug 03, 2012 3:57 am

Hi I have been searching for a solution to my 1956 356 electrical problems.

My engine runs well then starts to sputter before dying. everything has been looked at and carbies are fine.

here are some facts:

- 6 months ago a new engine was put in

- the car had a 6v to 12v conversion. now i know that there are different qualities of conversion and seeing some of the other things done to the car I would not be surprised if there were some short cuts, maybe in the guages

- since the engine changed the radio and temp gauge stopped working

- the car ran for a weeks or so then started to have dimming lights, sputter then die. Battery flat and not charging

- everything was replaced. battery then regulator and distributor. more earths. the generator apparently was tested and was fine but after the electrician said it was the only possible thing left so it was changed with a reconditioned one.

- now 6 months later the car is doing exactly the same thing.

could it be something to do with the guages? - temp guage in particular?

please help. I am tired of spending a fortune on mechanic's misdiagnosis

Fri Aug 03, 2012 10:49 am

The problem is not so easy to diagnose without testing. If your new battery drains like you say there is either an open circuit or a short circuit.
However a short circuit would normally blow a fuse where an open circuit with just a break in a wire will stop current flowing to the component in question.

There is probably a voltage dropper fitted to the wiring for the gauges how are the connections on that? Have you been all over the connections to the fuse box and checked for continuity of the main wiring? It seems strange it worked okay for 6 months after the first problems. Was the voltage regulator new? If that is playing up then it could cause charging problems
which could lead to your current situation.

If you fully charge the battery does the red generator light go out on start up. Does the ignition switch work well?

Sorry, without some form of electrical testing it probably will be difficult to find unless you find loose wires, bad connections, broken wires that are obvious to see.

Maybe, someone else here has a more simple answer.

Hope you find the problem.

Roy

Fri Aug 03, 2012 11:18 am

How often do you drive the car? A generator can depolarize if it's been sitting for a few months. And your symptoms do indicate a charging problem/running on battery only.

Fri Aug 03, 2012 6:04 pm

$.02 from another direction....

Sounds very like a recurring grounding problem to me. Possibly compounded by a slow drain that could contribute to recurring corrosion at the ground point.

Temp gauge; Two possibilities:

1. A crude resister installation has failed.
2. Its not hooked up because someone didn't want to screw with it.

Same for the radio.

Sat Aug 04, 2012 4:15 am

I think Mr Szabo could well be correct about the grounding. Thinking about it although you advised the earths had been checked have you made sure the copper strip engine/ transmission earth to chassis is perfect. If that copper strip similar in look to the earth strip on the battery is not perfectly clean could well cause a problem.

Look underneath and don't just tighten it but take it off ( and the battery one as well ) and really clean it.

Roy

Sat Aug 04, 2012 1:47 pm

From the description it seems the problem was fixed and then returned. Did replacing the generator fix the problem? The headlights dimming seems to be the only relevant piece of information as far as diagnosing the problem, and that would be because the battery is not charging, or the battery is bad. You should do a load test on the battery, either in or out of the car to make sure it is OK. Take it to a local autoparts store and have them test it. Then with the engine running, check the voltage at the battery while the engine is revving at least 2000 rpm. It should be about 14.5V. If that is the case, then the battery is charging and the regulator and generator are OK. Next turn everything off and disconnect and re-connect one of the battery terminals. If there is a spark, even a small one, there is something that is "on" even though everything should be "off" and it is draining the battery. There is no way that we will know what that thing is. It could be the clock, or it could be a voltage converter for the radio, or something. If you place a ammeter in series (in between) the battery connections, ie. disconnect the battery and then connect one lead of the ammeter to the battery and the other lead to the connector, it will register some current. Then you can disconnect things one by one to see which is causing the current drain.

Unfortunately, in order to perform electrical tests, you do have to have some basic testers, like a multimeter, and you have to know how to use these tools which means understanding how electrical circuits work. Without this knowledge, you can easily cause real problems or become frustrated at not being able to find a solution.

Sun Aug 05, 2012 2:12 pm

jhoefer wrote: How often do you drive the car? A generator can depolarize if it's been sitting for a few months. And your symptoms do indicate a charging problem/running on battery only.

Thanks for the quick reply. The car is a daily driver. I know normally it would be a generator but 2 x generators in just over 6 months seems odd. That's why I'm hoping someone might know if it could be something else before revisiting the the same repairs

Sun Aug 05, 2012 2:21 pm

Thank you do much for all your replies. I really appreciate your time and answers. The battery was replaced and the problem persisted. One question, one thing is car not starting but what do you think would cause the sputtering before dying when driving?

Sun Aug 05, 2012 3:16 pm

The battery is becoming drained while you are driving. The headlights dimming indicates that. But of course, it could be running out of gas or flooding...

SV

Sun Aug 05, 2012 8:27 pm

Mr.larsmula:

All your symptoms are related to the main problem(s).

It would seem safe to assume that you are draining batteries and the chargeing system either cannot keep up or is adding to the problem. I would further speculate that these may well be two separate, tho related, problems.

Electrical problems require patient diagnosis and maybe some trial and error, all best conducted first hand, and you have had some good advice about ways to do some basic diagnostics. However, long-distance advice to unpracticed/unwilling hands renders the exercise moot and makes further productive counsel from afar impossible.

With no intent to criticize per se, I think perhaps you need to address the idea that your present mechanic is in well over his head. You might want to look around for a fellow that has a multi-meter and knows how to use it.

Good luck.

Mon Aug 06, 2012 1:02 am

I agree with mr Szabo, so many things could cause the engine to fail. for example the coil maybe the windings fail with temperature, maybe the connections in the distributor are not correct, maybe.......

Take it to an auto electrician is probably the best idea. He will polarize the generator etc etc. It needs a multi meter man. Of course as said above fuel, fuel pump, blocked jets, faulty petcock etc etc.

Very difficult from a distance to advise.

Roy