Drivetrain I Need Big Help! Please, Keep Blowing Starter Solenoid

5point0stang88

Active Member
Sep 9, 2011
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I replaced my starter with a reman, because previous has stopped engaging and blew my solenoid.
Since, I have blown maybe 4 starter solenoid. In a week. Including the heavy duty 100 amp from Napa
Before I get the mini starter, what should I check to be culprit? I've cleaned battery connection and engine ground wire, and even have wire from negative post to screw that mounts solenoid to the fender.
 
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Blew the solenoids? I have had them stick, and have had some click and not work on an older car. What happens when they blow?

@jrichker has a complete starting system checklist he has posted. You will need a good multimeter to check the wires for resistance and voltage drop. I would go through the checklist before I risked wrecking a new mini starter.
Here is a place where he posted the checklist when I had a sticking solenoid.
Electrical - need starter second opinion | Mustang Forums at StangNet
 
Blew the solenoids? I have had them stick, and have had some click and not work on an older car. What happens when they blow?

@jrichker has a complete starting system checklist he has posted. You will need a good multimeter to check the wires for resistance and voltage drop. I would go through the checklist before I risked wrecking a new mini starter.
Here is a place where he posted the checklist when I had a sticking solenoid.
Electrical - need starter second opinion | Mustang Forums at StangNet
When I shake the solenoids, the insides make noise
 
Rattles are not normal. So they do they just not work or do they stick with the starter still going and going first?

Either way, the multi meter is your friend.
12.76 v at battery key off
12.76 v between starter and each big post of solenoid.

12.45 at battery key on
between starter and each big post of solenoid.

12.35 at battery cycling crank

I have continuity between both big posts of solenoid.

10.2 v at small posts key off
10 v at small posts key on
 
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Rattles are not normal. So they do they just not work or do they stick with the starter still going and going first?

Either way, the multi meter is your friend.
Ok something tells me that I should not have continuity between ground and the wire that is connected to starter, but I do. I can tell it's grounded because I have over 12v between positive and starter wire. Same as positive and engine ground.
 
Common problem on these cars.

  • Check that ALL grounds are tight,shiny and clean
  • Check that the mounting holes and area where you bolt the starter solenoid is clean and shiny.
  • Check that your battery is not drained, a weak battery will cause starter solenoids to fail
  • Check your starter that it is not drawing too much voltage, and/or shorting out
  • Check that your 2ndary ground strap from the battery to the post behind the battery is there.
  • Check that your ignition switch- the one under the dash on the steering column is not hanging up.
  • As mentioned do a voltage drop test from the battery to the solenoid, from the solenoid to the starter with the key off and on.

Does your car continue to crank after you release the ignition key? Having any problems with your dash lights, radio or other windows?

What may also help is to install another small ground from one of the mounting bolts on the starter solenoid to the negative battery cable. Also I would only recommend a FOMOCO starter solenoid. Aftermarket ones tend to be junk.
 
Common problem on these cars.

  • Check that ALL grounds are tight,shiny and clean
  • Check that the mounting holes and area where you bolt the starter solenoid is clean and shiny.
  • Check that your battery is not drained, a weak battery will cause starter solenoids to fail
  • Check your starter that it is not drawing too much voltage, and/or shorting out
  • Check that your 2ndary ground strap from the battery to the post behind the battery is there.
  • Check that your ignition switch- the one under the dash on the steering column is not hanging up.
  • As mentioned do a voltage drop test from the battery to the solenoid, from the solenoid to the starter with the key off and on.

Does your car continue to crank after you release the ignition key? Having any problems with your dash lights, radio or other windows?

What may also help is to install another small ground from one of the mounting bolts on the starter solenoid to the negative battery cable. Also I would only recommend a FOMOCO starter solenoid. Aftermarket ones tend to be junk.
Thanks all the above was addressed, I have ground wire from battery to solenoid.

I have found that the wire going to the starter is grounded in my last post. I'm about to pull off the starter and wire to see what's going on there and will report back
 
Thanks all the above was addressed, I have ground wire from battery to solenoid.

I have found that the wire going to the starter is grounded in my last post. I'm about to pull off the starter and wire to see what's going on there and will report back


Wait- the + power wire from the solenoid to the starter is grounded- how?

This wire is grounded?

63663d1236962797-1988-mustang-5-0-starter-removal-help-img_1328.jpg
 

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You can see there is no protection on the cable in your picture. Take the cabe off and cover the end shrink wrap and then the entire cable in wiring loom. Also bend it out so it is not so close to the block.

63662d1236962660-1988-mustang-5-0-starter-removal-help-img_1271-1.jpg
 
If that beep means 0 ohms, it is a wonder no cables were melted too! I have seen them smoke on a C#{>y.
Just for luck, have them bench test the new one before leaving the store. That one looks Purdy enough to still be under warranty. If it sounds suspicious, do not put it on. They get thrown around in shipping.
 
Holy moly. that engine bay looks like a wiring nightmare. Those battery cables should be replaced... Definitely have them bench test that starter. I would replace the starter and the solenoid at the same time. with a FOMOCO unit.
 
Holy moly. that engine bay looks like a wiring nightmare. Those battery cables should be replaced... Definitely have them bench test that starter. I would replace the starter and the solenoid at the same time. with a FOMOCO unit.

I was going to be too polite to mention it, but Milestang63 is usually right on, this time about a real solenoid and the wiring. I bet you have a project planned to get it safer and looking better. And I had even BW (the Borg, which was the premium line) solenoids stick for no reason.
 
Thanks for the suggestions, the old starter they attempted to bench test, and it started smoking, so yeah it was bad. I had them bench test the replacement as well and it was fine. I also got new 4 gauge wire for starter to solenoid. It cranked fine. I'm gonna return the 80$ Napa 100amp solenoid

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