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car keeps running after pertronix install

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mgbmedic

mgbmedic

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I've got a friend who just bought a 76 MGB roadster and has been cleaning under the hood, possibly removing wires and who knows what. Installed a new pertronix ignition and when the starter is engaged, it does not disengage until the battery is cut out. Any thoughts?
 
Check key side of solenoid as engine coil is still hot after key off.
 
With Midgets it is a diode issue somehow related to the emission stuff. Try unplugging the brake fail switch plug. (The one that goes into the splitter) see what happens.
 
E-Brake switch as well.
 
A 1976 would likely still have had the ballast ignition system. That system will include a white/yellow wire running from the starter solenoid to the coil (+) terminal. If your friend took the wires off the solenoid it is likely that he/she has moved the white/yellow at the solenoid from a switched terminal to one that is always hot. (Where all the brown wires are).

If this is what he/she finds, they need to correct this connection not only so they can stop the engine but also to prevent damage to the Pertronix module. The original Ignitor module is not supposed to be powered up for more than 3-5 minutes without the engine running or it will overheat and fail.
 
Still havent solved the problem. Took starter/solenoid off and had Autozone test it and it passed. Now for the weird part... starter still engaged when starting, even with key off stays engaged, but as i turned to pull a lead off the battery, my hand hit the turn signal switch and the starter disengaged. Havent seen green pea soup coming out of the vents, so probably not possessed. BTW, Autozone says they have the starter, must be ordered, lists for $79.95. Not a bad price if it's correct. Brake fail switch- is that the 2 wire plug under the master cylinder?
 
Sounds like a ground issue.
 
This really sounds like an inadvertent wiring error to me. But in any case, I think you need to take a systematic approach to troubleshooting it. Start by checking for voltage at the solenoid's control terminal, using a voltmeter or a test lamp, when the key is released. That will tell you if it's just that the solenoid is sticking. If you find voltage, disconnect it and try operating it by hot-wiring from the battery. If it stays on when you remove the power (unlikely) there is some kind of bridged connection inside the solenoid.

This starter has an integral solenoid, doesn't it? In my experience, they are prone to sticking.
 
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Problem solved...sort of. After checking solenoid, starter relay, installing new turn signal indicator and new ignition harness...problem still existed. Turn signal still killed the engine when turning key off didn't. After cooling off ( this is a good time to leave the garage and go to my happy place ) it dawned on me to just pull the fuse on the turn signal circuit. It worked! So I called my friend and asked if he did anything to the car since he bought it. Ahhhh...he installed a emergency flasher switch on the console...all by himself. I will check that tomorrow, looks like a good lead to further isolate the problem. Thanks to all for the help, Bob
 
Apparently, you can install an emergency flasher switch upside down, as this fixed the problem. Sheesh, glad it's over. Thanks to everyone who replied, again, this is the best forum, ever. bob
 
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