Triumph Repair: TR 6 starting problem, starter solenoid, tracer wire

Question
QUESTION: Hi: I have a 1974 TR 6 that I have redone and it has developed an intermitent starting problem, at times when I turn the key all get a buzzing sound from under the dash, if I get a push it starts then if I turn it off and turn the key it will start, any suggestions would be greatly appreciated.

ANSWER: Hi Don,
You need to put a test light or volt meter on the starter solenoid on the post that has the small white w/red tracer wire on it at the time when you hear the buzzing and it don't start to see if you have current going to the solenoid. If you do, you need to put a volt meter on a low volt scale and put the "positive" lead on the positive post of the battery (not the cable end) and put the "Negative" test lead of the volt meter on a clean metal part of the engine and go to the "Start" position and when it buzzes read the meter. If you see more than .5v then you have a bad cable connection either at the battery or at the solenoid. You need to run the same test on the negative cable by connecting the negative test lead of the volt meter to the negative post of the battery (not the cable end) and the positive test lead to a clean metal part of the engine and try the starter again when it just buzzes and read the meter again. Again you must not see any more voltage than .5v on the meter. These are called "voltage Drop" tests of the cables.
Let me know the results of these tests and I will give you the next step.
Howard

---------- FOLLOW-UP ----------

QUESTION: Thanks for your reply, I checked things as per your suggestion and it checked out ok.

In the past few day I have rechecked all connections to the starter motor, the battery gound, ignition switch, etc. they all seem ok,

I have discovered the following, I have a disconnect switch on the battery, and have found that when I try to start the engine and hear the buzzing sound if I turn the disconnect switch off and of while holding the key in the start position the car starts, it seems that a surge of power while the key is in the start position resets something. I also removed the disconnect switch in case that was the problem and it did not make any difference - still that buzzing noise. If it makes any differece that buzzing noise seems to be coming from behind the dash.  Any further suggestions.  

Thanks for any further suggestions.

Answer
Don, if you do what I had suggested you would have fixed the problem as that is the standard method of running the tests for a starter problem and it is a 100% test. Meaning it can not fail if you follow it a step at a time. Trying to diagnose any electrical problem by symptoms is a waste of time. Run the tests I out lined and you will find the problem.

Howard