QuestionQUESTION: Mr. Fitzcharles,
Thank you for your prompt reply. I followed your directions on the voltage drop tests, and the negative cable checked out with only 0.03V between the negative post and engine. The positive between the positive post and the positive post of the solenoid however had a resting voltage of 1.8 - 2.7V and shot to 13V when I turned the ignition key.
I pulled all connections to the solenoid and cleaned them up, and had some temporary luck connecting only the line that goes to the bottom fuse position and then to the dash direct to the positive line coming from the battery (bypassing the solenoid). This at least powered on the headlights/dash lights/horn, whereas activation of any of these switches had previously caused system voltage to drop to 1V. However, the lights would turn on, but visibly dim if the horn button was pushed. Often the horn would not sound at all if the headlights were on.
I wanted to try and bypass this line from the solenoid to the dash and attempt to start the car. I disconnected the brown input line from the wiring harness and while the harness was still connected, applied current to the brown pole of the ignition module. This succeeded in producing the clicking (from the fuel pump?) which had not been happening previously, but no sound from the solenoid.
I read another article of yours regarding direct application of current to the solenoid to try and test the module, however that was an earlier MGB. Is there a way to try it with the negative earth model? Every time I think I'm on the right track what worked quits working and what I thought was the problem starts to work.
Thank you again, Travis
ANSWER: You found the problem when you tested the positive cable so you need to fix that before proceeding and you are just wasting time with bypasses of any kind.
Howard
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QUESTION: Mr. Fitzcharles,
My problem is that I don't know how to interpret the test results, or how/where to look in order to remedy the situation.
As of now, with everything put back together, turning the ignition key results in clicking of the fuel pump and only a half-hearted partial turn of the starter. The engine makes a partial rotation and then stops abruptly. On very rare occasions this is enough to start the car. A voltmeter between the positive post of the battery and the positive post of the solenoid shows 13V resting and drops to 4V upon attempting to start.
I don't know how to interpret the data to figure out whether I'm dealing with a short in the positive current somewhere in the car or a bad starter motor.
Thanks, Travis
ANSWER: Travis, you are doing something wrong on your voltage test. It is impossible to read 13v with a volt meter between the positive post of the battery and the same positive post of the solenoid with out a load (starter working). It sounds like you are connecting your volt meter between the positive post of the solenoid and the negative post of the battery. Unless you have the battery installed backwards with the positive post of the battery connected to ground.
Howard
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QUESTION: Mr. Fitzcharles,
I'm sorry, those were supposed to be two different observations that ran together. You are correct, they are supposed to be:
1) Voltmeter from negative post of battery to positive post of solenoid: 13V resting and a drop to 0.2V upon turning the ignition.
2) Voltmeter from positive post of battery to positive post of solenoid: 0V resting and 13V upon turning the ignition.
I believe these two things should tell me something but I don't know what it is or how to proceed from here. Today turning the ignition did not actuate the starter at all today whereas yesterday it had. No changes had been made and the battery had been disconnected in the meantime.
-Travis
AnswerTravis, think about what you are doing with the volt meter. If you have a strand of cable and nothing else and you connect a volt meter to each end of the cable and you see 13v. doesn't that tell you something? How can you get 13v when you connect a volt meter to each end of the same cable? The ONLY way is that you have a bad connection on one end of that cable and your volt meter is making the contact instead of the cable. SO fix the cable!!
Howard
