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Engine wont shut off!

coachcal

Full Member
Joined
Apr 14, 2011
Messages
212
'74 with a 302.

Recently replaced all cables from battery starter and starter Sylenoid (sp?). I only did this because they looked corroded. I have been driving it for about a week after changing the new parts. Now all of the sudden it will start up fine but will not shut off.

I turn the key to the off position and remove it but it keeps running. Have to disconnect the coil to get it to shut off. Also have to disconnect the battery or the radio would stay on.

Any help?
 

Steve83

Bronco Guru
Joined
Jul 16, 2003
Messages
8,980
Loc.
Memphis, TN, USA, Earth, Milky Way
...starter Sylenoid (sp?).
...
Any help?
Sure! ;D It's spelled "relay".

.
Have to disconnect the coil to get it to shut off. Also have to disconnect the battery or the radio would stay on.
Your ignition switch is bad, or a hot wire has come loose & shorted to the others. Look at the back of the switch, & this diagram:

 
Last edited:

DirtDonk

Contributor
Bronco Guru
Joined
Nov 3, 2003
Messages
47,345
I would say also coachcal, that another possibility is that your old relay/solenoid/thingy has gone belly-up and is sending current through the little Brown "I" wire on up to the coil.
It's unusual, but not unheard of.

Otherwise, as Steve says, the most common issue would be a bad ignition switch.
Unfortunately though, as he also said, you need to to some tracking, because any kind of fault or short that lets any voltage get to the Red w/green wire to the coil can keep the engine running.

My thinking was that, since you were messing with the starter relay a couple of weeks ago, that would be where I'd look first. It's also the easiest to diagnose, since all you have to do is pull the Brown wire off and run the engine again. See if it helps.

Good luck. And yeah, sylenoid and cylenoid seem to be the two most common mis-spellings here. So you're in good company.
And "relay" IS easier...

Paul
 
OP
OP
C

coachcal

Full Member
Joined
Apr 14, 2011
Messages
212
I just noticed one more issue. Apparently when I was running one of the battery cables I pulled a wire free from something. It is in the bundle running right behind the RELAY. It is black and white and says "compressor" on it. I haven't had a chance to chase it down to see if I can tell where it goes. I assume the obvious 1st option would be AC compressor.
 

DirtDonk

Contributor
Bronco Guru
Joined
Nov 3, 2003
Messages
47,345
What wiring harness are you running? None of the factory wires had descriptions on them.

And back to your first issue, I forgot that your radio stays on too. Kind of leads one back to the ignition switch itself again.

A quick test of something like the heater blower might tell you. If it runs with the key off, then you've got power out from the switch still.
If you have a voltmeter though, of course you can tell more things, but the simple tests are fun and rewarding too.
And beat the heck out of turning upside down and inside out under the dash. Any day of the week!

Paul
 

DirtDonk

Contributor
Bronco Guru
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Nov 3, 2003
Messages
47,345
It's a fiendish thingy. One of many on a Bronco.

Paul
 

JLBachs

Full Member
Joined
Feb 4, 2011
Messages
333
Had experience with this last week. The solenoid was bad and current was going from the tan wire on the "I" post on the solenoid to the coil. You should be able to confirm this by disconnecting the tan wire. The solenoid is relatively inexpensive and replacing offers the opportunity to uprade to the new style if you like that sort of thing.
 
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