engine wont turn off
Thread Starter
Heel & Toe
Joined: Jun 2006
Posts: 21
Likes: 0
From: birmingham
engine wont turn off
I have a mind boggling problem.Today I have started the engine in my 1980 vette for the first time since pulling the body off 12months ago to restore the chassis.(90% back together now).
Here's the problem.I turned the engine off by the ignition switch and it continued to run.OK I thought,possibly a bad or wrong connection keeping the system live.I quickly disconnected the battery thinking no power to raise a spark at the plugs, engine will stop running,right?. WRONG!!!!!. It continued running with battery removed and did not stop until i caused it to stall by disconnecting all the spark plug leads.
Someone may have a logical explanation for this and a simple fix, but at the moment I am baffled. To me this is an impossible scenario. No battery power = no spark to ignite fuel.any suggestions?????
Here's the problem.I turned the engine off by the ignition switch and it continued to run.OK I thought,possibly a bad or wrong connection keeping the system live.I quickly disconnected the battery thinking no power to raise a spark at the plugs, engine will stop running,right?. WRONG!!!!!. It continued running with battery removed and did not stop until i caused it to stall by disconnecting all the spark plug leads.
Someone may have a logical explanation for this and a simple fix, but at the moment I am baffled. To me this is an impossible scenario. No battery power = no spark to ignite fuel.any suggestions?????
Melting Slicks
Joined: Jul 2005
Posts: 2,545
Likes: 3
From: 406ci SB, AFR 180 Heads - 490 HP @5,600 RPM 529 lb-ft @ 4,100 RPM
Engine running, no battery ? sure you don't have a wire wrong going to the alternator thats the only thing that can still produce current after the battery is disconnected, I believe
Le Mans Master
Joined: Dec 2007
Posts: 6,422
Likes: 591
From: McHenry Illinois
The batterys only purpose is to store power in order to start the engine and to provide power in case there is a intermittent load larger than what the alternator can suppport. That being said, there is no reason that the engine should turn off just because the battery is disconnected. On an engine with HEI, the power to the dizzy must be interrupted. you have wsomething wired up wrong. check with the ign switch turned on, engine not running, to see if there is voltage at the distributor power wire (large red wire that attaches to the drivers side of the dist.) check the same with the ign switch off. Should be 12 volts with switch on and 0 volts with switch off. If those are correct go ahead and start the engine then turn it off. If it will not die, then the alternator is somehow feeding the ign circuit. To get it to turn off simply disconnect the red wire from the dizzy. Next try unplugging the alternator plug and try it again.
Le Mans Master
Joined: May 2002
Posts: 5,086
Likes: 786
From: Lebanon Township New Jersey
The batterys only purpose is to store power in order to start the engine and to provide power in case there is a intermittent load larger than what the alternator can suppport. That being said, there is no reason that the engine should turn off just because the battery is disconnected. On an engine with HEI, the power to the dizzy must be interrupted. you have wsomething wired up wrong. check with the ign switch turned on, engine not running, to see if there is voltage at the distributor power wire (large red wire that attaches to the drivers side of the dist.) check the same with the ign switch off. Should be 12 volts with switch on and 0 volts with switch off. If those are correct go ahead and start the engine then turn it off. If it will not die, then the alternator is somehow feeding the ign circuit. To get it to turn off simply disconnect the red wire from the dizzy. Next try unplugging the alternator plug and try it again.
Good explanation and advice.
Racer
Joined: Nov 2007
Posts: 320
Likes: 0
From: Upstate New York
If your battery cable to the starter is touching the 'R' terminal on the solenoid it will keep power going to the distributer and the engine won't shut off.
Don't disconnect the battery when the engine is running, it's bad for the alternator diodes.
Don't disconnect the battery when the engine is running, it's bad for the alternator diodes.
Melting Slicks
Joined: May 2007
Posts: 3,246
Likes: 4
From: Bay Area CA
The batterys only purpose is to store power in order to start the engine and to provide power in case there is a intermittent load larger than what the alternator can suppport. That being said, there is no reason that the engine should turn off just because the battery is disconnected. On an engine with HEI, the power to the dizzy must be interrupted. you have wsomething wired up wrong. check with the ign switch turned on, engine not running, to see if there is voltage at the distributor power wire (large red wire that attaches to the drivers side of the dist.) check the same with the ign switch off. Should be 12 volts with switch on and 0 volts with switch off. If those are correct go ahead and start the engine then turn it off. If it will not die, then the alternator is somehow feeding the ign circuit. To get it to turn off simply disconnect the red wire from the dizzy. Next try unplugging the alternator plug and try it again.
Car was running on alternator, & ignition switch isn't functioning correctly
