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Mini starter won’t stop spinning over with engine running

889 views 15 replies 5 participants last post by  Blown and strocked 
#1 ·
I am building a 66 mustang and installed a 91-93’ PMGR mini starter. When I turn the key the car starts but the starter stays engaged, I have replaced the ignition switch, and starter solenoid, and it still stays engaged.

The starter is wired correctly for a PMGR starter, with starter cable relocated to + post of solenoid and trigger wire on the normally open post.

How can I test to isolate the starter as the problem? The other possibility is that I don’t have a resistor on the green/red wire coming from the alternator to the ignition switch (regulator now bypassed due to using 2g internally regulated alternator). This somehow may be backfeeding the ignition.

The starter does stop running when I turn ignition off so it’s not a run on condition.
 
#2 ·
Does it just stay engaged for a few seconds after starting or does the starter just not shut off? I just went through the overrunning starter deal on my car in the fall, which ended up being incorrect wiring at the solenoid. I swapped things around and walah.....I didn't need that $200 mini starter after all lol.

I know it isn't the corral but see below....this got me pointed in the right direction.

starter stay engaged 3 secs too long - MustangWorks.com : Ford Forums
 
#3 ·
remove the starter heavy cable after you disconnect the battery

reconnect battery

and start testing how you switched signal is working

does come on and off like it should??

voltage test
 
#4 ·
I had some time to test today.

Remove starter cable as Indy suggested. Tested fender mounted solenoid and it tested good and cycles on and off giving power to the starter when it should.

Hooked wires back up and disconnected the coil and the starter turns over as it should and stops when disengaged.

Checked voltage to all cables and checked good. The only thing I can think of is somehow the ignition continues to supply power when the key is released.

I am running a MSD 6AL2 with small red wire powered to the ignition switch. How can I test for feedback?
 
#6 ·
Are you sure the solenoid wiring is right? Sounds exactly like what I and many others have had. There are known issues with the ignition switches in these cars so that could be a possibility as they age.
 
#7 ·
The starter is wired as follows:
Starter cable relocated from original stock location of solenoid to the battery sided solenoid , a 12ga wire was added onto the post where the starter cable was initially and is run to the spade connector on the starter. Ignition trigger wire run to the small S post on the solenoid.

The ignition switch was also replaced recently to rule it out as the problem.

The solenoid is new from Advanced Auto (Chinese junk), but from my tests it is working and circuit is opening and closing during test.
 
#8 ·
I had the same problem, my issue ended up being the solenoid on the starter was staying engaged even after the starter relay was disengaged. Ended up being able to apply 12 v to the starter off the car and see it was staying engaged. got a new solenoid from advance auto, so far so good.

strange feeling to hear the starter staying engaged after the car starts. lol.
 
#9 ·
I am planning to pull the starter off the car and test it off the car to see if the armature hangs open and doesn't retract. Then after that I don't know. Getting frustrated and going to start throwing parts at it (maybe literally).

I think that I eliminated the possibility of the MSD box sending supplied power to solenoid and hanging the fender mounted solenoid open by running the ignition trigger wire through an additional relay.

So its got to be the solenoid on the starter. Ive got to get this car moving in the next to weeks because I am moving to a new house and don't want to pay someone to trailer the car there, needs to be driven.
 
#11 ·
12.2 volts at the battery
12.2 volts at the battery side of the solenoid, 0 volts at the starter side, when circuit is open
12.2 volts at the red/blue ignition trigger wire when voltage is key is in the ON position, 0 volts key off position.
12.2 volts to the starter side of the solenoid when solenoid is triggered at the S terminal, circuit closed, 0 volts when open

Continuity checked on the fender mounted solenoid, positive cable, starter cable, and ground cable to block, 2nd ground to firewall, and 3rd ground cable from block to frame. Found the cable to starter to not be completely tight but had no effect on my problem.

In typing this I may have realized my problem which i will investigate more tomorrow. I should only have 12v to the S terminal when cranking not when the key is in the ON position, so I am getting power from somewhere I shouldn't to ignition.
 
#13 ·
Wiring mods...........what have I not done lol.

Wiring alteration summary:
Factory fuse block deleted because it was a rats nest and full of corrosion. Factory fuse block was replaced with 2 fuse blocks that use modern ATC fuses. The fuse panels separate out circuits that are hot all times and hot only when ignition is in the ON or ACC position.

I built a power distribution panel that holds my MSD 6AL2 box, 4 relays, a 10 terminal fuse panel, 150amp breaker, and 2 buss terminals, and is mounted under the dash. Presently, only one of the relays is being used for powering the electric fuel pump when the key is powered on. Power for the panel is supplied from a 300AMP buss terminal by the battery via a 10 gauge wire.

The MSD key on power is connected to the red/blue ignition wire leading to the s terminal of the solenoid.

The alternator is a 2G from a fox body mustang using a foxbody 2G alternator harness (will eventually go 3g, but is what it is for now). The factory voltage regulator is not used and the green/red wire from the alternator is connected back to the green/red wire that formerly went to the external voltage regulator.

All I can think to do at this point is power on the ignition and start subtracting circuits until I find the one sending power to the switch in the ON position.
 
#15 ·
Yesterday, I checked the voltage at the fender mounted solenoid and I was incorrect in my earlier statement. There is 0 v at the S terminal with the key on. I wanted to test the power at the S terminal while the key is in the start position but I didn't have a helper (maybe this weekend). I did pull the starter and may have found the problem. With the starter off the car jumper cable grounded to body of the starter, and positive jumper to the solenoid big post. As soon as I jumper the + to the S terminal the solenoid engaged the motor and wound not shut off (jumper removed), had to smack the solenoid with a hammer to get it to disengage.

After the solenoid disengaged on additional attempts the bendix would push out the gear but not spin the motor.
 
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