QuestionQUESTION: Hi Howard,
My 1977 Spitfire has been starting and running well recently until it failed to start after a fairly long run. Ignition was completely dead - starter motor wouldnt even try to turn over but she did jump start ok and i run her home for around 35 miles. When i stopped she wouldnt start again. I think the solenoid has had it but i noticed the coil was extremely hot -too hot to touch for more than a couple of seconds. On testing it, the coil appears to be a 6v and i have what looks like the pink/white and white/yellow ballast resistor wires coming from the coil. Has my resistor system failed therefore making the coil get hot? Would the lack of a resistor fry the solenoid too? Is the remedy to cut both resistor wires and just fit a 12v coil? I have a solenoid on order but im now wondering about the coil/resistor system being the problem which will reoccur if i dont sort it. Many thanks in advance, Tony
ANSWER: Hi Tony,
The Pink w/white stripe is the resister wire to the coil and the white w/yellow stripe is the direct 12v power from the solenoid (in the "Start" position only).
You need to test the wiring of the car to see that it is not causing the overheating of the coil. To do this first remove the White w/Yellow stripe wire from the coil but leave the Pink w/White stripe wire on the coil. Pull the coil wire out of the distributor cap and ground it.
put a volt meter (+) test lead on the (+) post of the coil with the lone Pink w/White stripe wire. Turn the ignition to "ON" (not start) and rotate the engine slowly. (put it in 4th gear and role it forward). You should see the voltage change from 12v to about 6v and back to 12v etc as you slowly rotate the engine.
Now with the key still in the "ON" position test the White w/Yellow striped wire for power. There should be nothing.
Now turn the key to the "Start" position and you should see 12v on the White w/Yellow wire.
All of this is with a solenoid connected and a charged battery.
The US and the UK cars are wired the same in this area of the car.
My guess is, if you run these tests, you will find someone has wired the car wrong and there is power on the White w/Yellow striped wire while the key is in the "ON" position causing 12v to the coil at all times.
However, keep in mind that a coil will get hot if the ignition is left on and the engine not running if the electronic ignition is in a position to have the coil on or if it were a pointed ignition system with the points closed.
The starter solenoid can not be destroyed by the ignition system. The only way a solenoid can be damaged it to be left in the "Start" position for extended time. Some times one can have it's contacts burned by operating it often with a very low battery or with a shorted out starter motor.
When you put on the new solenoid, you should run a battery load test and a starter amp draw test. Also run voltage drop tests on the (+) and (-) cable system. Then when everything is operating test the alternator output. If you are not familiar with these tests let me know and I will go over them with you.
let me know.
Howard
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QUESTION: Hello again Howard
Thanks for your very helpful reply. I had another look at the coil/solenoid wiring and I dont seem to have a white w/yellow wire running from the solenoid to the coil. All wires from the coil go into the main wring harness that goes to behind the dashboard. The only wires i have going to the solenoid are the four brown (2 thick/2 thin) wires, the positive wire from the battery and of course the connecting wire to the starter motor. There is also a white w/red wire that comes from the main harness from behind the bulkhead. Does this suggest some incorrect wiring?
I will carry out your other tests shortly. Thanks again,
Tony
ANSWER: Hi Tony,
You need to run the tests I outlined of the wiring at the coil. The fact that you have the correct wire colors at the coil and not at the starter solenoid is an indication some one put the wrong starter solenoid on the car and then changed the wiring which is most likely all of the problems.
If that car was brought to me in a dealership I would first get a wiring diagram of the car and take a 12v test light and a volt meter and start testing at the coil and work your way toward the power supply for each which is the ignition switch for one circuit and from the coil to the the harness near the starter solenoid for the other circuit.
If you don't have a diagram let me know and I will post one on my web site for you to copy.
In any electrical problem I always start at the load (the coil in your case) and start testing a joint at a time until I reach the source (the ignition switch for the one wire and the solenoid for the other wire) This method of testing is a 100% sure method of correcting a circuit and can not fail.
Howard
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QUESTION: Hi Howard
I did the coil tests you mentioned and i indeed got the change in voltage you talked about. Looking at my coil and solenoid in conjunction with a wiring diagram, my coil has all the right wires but the white with yellow tracer wire doesnt come from the solenoid butf rom somewhr behind the dash (i havnt found where it goes yet). Other than that my solenoid is also wired correctly.
I also did some tests on the starter, solenoid and cables using my test light. The top post of the solenoid (the one with all the brown wires) has power all the time. The white with red tracer wire that comes from the ignition has power when the ignition is turned to start as it should. However i have no power at the bottom post of the solenoid nor at the starter motor. My battery is charged (showing 12.6 volts) and i am using the new solenoid. Could I have been sold a duff solenoid and whats the best way to test it? But I have tried jumping the starter from the battery and nothing happens (no sparks either).
One other thing. When i was turning the ignition to do the above tests i went through 3 blown fuses in the fuse box in the paasenger side - each time it was the middle one that controls the guages, indicators wipers. I must have a short somewhere i guess but i cant seem to find anything wrong. But i mention it in case it gives you a clue on my main problem.
So the car still starts on a jump start but i cant even illicit a click sound from the solenoid or starter and the car shows no sign of turning over on the key. I thought it might be the ignition switch but, as i say, i am getting power to the solenoid from the switch.
Many thanks for your help and patience so far!
Cheers, Tony
AnswerTony, What do you mean when you say "the car starts on a Jump start"? Here, we call a "Jump Start" when an additional battery is connected. Or do you mean a "Push Start"?
As I have told you when you have a resistor wire to power the coil (Pink w/white tracer wire) then you should have a White w/Yellow tracer wire at the coil. This should be ONLY powered when the key is in the "Start" position. If it is powered with the key in the "ON" position disconnect it from the coil.
Now test the solenoid. Connect one of the large posts to the battery cable and all of the plain brown wires. Connect the other large post to the starter motor only. Now you should have two small terminals on the solenoid. Take a test lead and connect one end to the battery post and ue the other end to just touch each of the small posts. One should do nothing and the other should activate the solenoid. Now you have IDed the starter wire that comes from the "Start" position of the ignition switch. (White w/red tracer)
Now put a 12v test light on the other small terminal on the solenoid and turn the ignition key to the start position and the solenoid should activate and the test light should light up. This will prove that the solenoid is correct. Now if that is true, connect a wire from that small terminal and run it to the (+) side of the coil and disconnect the "White w/yellow" tracer wire from the coil.
The system should now operate correctly. (other then your other electrical problems) My guess it that some one had tried to do some wiring and didn't know how and has connected wires where they don't belong. Thus causing shorts and the ignition not to operate correctly.
A wiring diagram is just a road map of the wiring of the car. The problem is that the factory puts all of the circuits on one piece of paper and it is confusing to read.
I learned that when you have several circuits with problems you need to follow only ONE of the circuits and I like to start at the "LOAD" (one item that don't work) and follow the diagram toward it's power source (the battery) checking along the road (diagram) with a test light until you reach the battery. NEVER TRY TO GUESS WHAT MIGHT BE WRONG AND FORGET SYMPTOMS!!! Run the tests only and often when you correct one of the failed circuits you will have found what is causing the others to fail.
Howard
