Starter Problems

Discussion in 'Classic Mustang Specific Tech' started by geordie, Sep 13, 2012.

  1. By your pics it looks like its been converted over to a ministarter and the wiring is not correct.

    here is a diagram that should help:

    A typical solenoid:

    Ministarter before and after wiring:

    The mini starter requires more current to energize the solenoid on the starter because it not only closes the contacts to spin the starter motor, it has to mechanically throw the bendix into the flywheel.

    The reason your car starts intermittently is likely because your ignition switch is going bad. The way the fender mounted solenoid is wired (by looking at the picture) it is only being used as a terminal tie point. It is not carrying that extra current required to energize the solenoid on the starter and it’s starting to take its toll on the ignition switch contacts.

    Other things you can look for (since you said your battery is in the trunk) is a heavy battery cable ground from the engine to the body and clean tight connections. Also in the trunk, look for a good ground from the negative battery terminal to the body.
  2. Thanks Tim65GT, I need to take a good look at the above. However, I dug out some old photos before the car was restored and afterwards. The Starter is the same one in both cases, so is the firewall solenoid, as part of the restoration an entire new Painless wiring system was installed. You can see that before the restoration the battery positive is connected to the starter through the Battery In post on the solenoid, there is a hook to the output side of the solenoid........similar to your mini starter diagram above. The current set up on the right of the attachment to this, has the battery positive to the starter on the Out to Starter side of the solenoid and nothing on the Battery In post of the solenoid, clearly the solenoid is serving no function in this set up......
    Looks like you're on to something Tim65GT.....thank you.....
    So I think the next stage is to rewire the solenoid and replace the ignition switch....

    Attached Files:

  3. Tim65GT, what wire gauge would you recomend for the 'hook to output side of solenoid' in your diagram. Thanks in advance.
  4. 12 or 14 gauge would be good. Make sure it's protected from the heat where it gets close to the exhaust. Also make sure the ring terminals are crimped good. Soldered would be better. A lot of the times I do both. Here is a link to an old post with some pics of some crimping and soldering:
  5. Guys,
    It's been about a year since I first posted this issue and after receiving some helpful advice.......I've done nothing. I need to get on this, as the problem is only getting worse. I tokk the car out at the weekend, it started first time. After a 15 mile run out I brought it back into the garage and turened it off. I immediately tried to restart it, with no luck. I gotta get thai fixed, I'm a littl out of my comfort zone, but I gotta get this fixed. I'm printing off the entire thread and I'm going to make a start.
  6. If it were me, looking at the photo's & such... Find the wire on the "S" terminal on the fender mounted solenoid/relay that goes to the small terminal on the starter. Move that 1 wire to the large post on the fender mount solenoid that has nothing on it. That "should" fix it.

    If the wire feeding the small terminal on the starter does "not" go to the "S" terminal on the fender mount solenoid, then you are going to need to figure out where "all" of the wires go back to, and where they are supposed to be. Hopefully, the only thing "really" wrong is tying the Starter Solenoid directly to the ignition switch.

    Good Luck!

    Side note: The fender mount solenoid doesn't really care which direction the current flows through the large terminals. All it does is short a large copper ring between the two posts.
  7. [quote="Side note: The fender mount solenoid doesn't really care which direction the current flows through the large terminals. All it does is short a large copper ring between the two posts.[/quote]

    Great. I'd been doing a little reading this week and that was the conclusion that I'd come to, nice to hear a confirmation on it. I'm determined to make a start (pun) on Sunday morning. Thanks.
  8. Referring to the attached, this is the wiring set up for the starter.
    The battery is located in the trunk, the (-ve) cable is connected to the base of the starter, hence the engine block, main ground. There is another large cable from the base of the starter to the chassis frame.
    There are two cables / wires attached to the starter a large one and a small red one.
    There are two large terminals on the solenoid, let's call them A and B, there are two small terminals marked S and I.
    From the battery the (+ve) cable is connected to one side of the solenoid, large terminal, lets call it post A.
    Connected to post A is also a large cable that runs down to the one of two large terminals on the starter.
    Connected to post S are two wires. One red wire runs down to a small post on the starter. It looks a little small to be 10 or 12 gauge.
    The other wire connected to post S I assume is the starter wire from the ignition key.
    There are other wires connected to solenoid posts I and A but I didn't investigate them as I'd already accounted for all connections to the starter.
    There is nothing connected the other large post B on the solenoid.

    So based on the rest of the content of this post and other reading, my plan is to replace the small red wire with a 10 or 12 gauge wire and connect one end to the starter and the other end to post B on the solenoid. When the solenoid is activated, the copper disc will connect the small red wire to the positive side. It would seem to me that the ignition switch is currently providing this connection. This may be damaging the contacts on the ignition switch causing a starting problem, but I'm out of my depth here. I plan to replace the ignition switch as well. Does this sound like a good plan? What is the other large terminal on the starter for?

    Attached Files:

  9. Sounds right to me. Before going too much farther, i'd try moving the small starter wire (red) to the other large post (B) and see if that corrects your original starting problem.

    The smaller wire size may not really be an issue, probably 16 or 14 gauge. See if the wire is hot after cranking the engine over, if it is, go to a larger size, if not, then it's likely not going to be a problem.
  10. Good advice, thanks.
  11. So yesterday I temporarily moved the small starter wire (red) to terminal B and secured it. The difference when I started the car was like night and day. Starting was effortless and every time, first time. I am very confident that this is the fix. Thanks to all who provided input to this thread !!! I decided to make a new harness of power cable and red wire, when I discovered that the existing red wire was spliced together out of three pieces of different gauges.

    Thanks again, I think I've got my car back again!!
    Iamdiffrnt likes this.
  12. All done, starts like a dream now.
    Iamdiffrnt likes this.
  13. Cheers!