Engine Kill ?
Thread Starter
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Joined: Jun 2007
Posts: 58
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From: Winston-Salem N.C.
Engine Kill ?
My engine will not shut off! i have replaced both the ignition switch and the cylinder lock (thought that would cure it) , it has shut off one time on its own (1 out of 5 trys). car does have an MSD box(not installed by me). not sure where to look next .
thanks,chris
thanks,chris
Safety Car
Joined: Nov 2004
Posts: 4,359
Likes: 57
From: Mundelein Illinois
Check 12 volts ignition wire under the hood by distributor. I don't know what year your car is but I think it would be pink wire. When key is turned off that wire should go cold.
A car shuts off because of the loss of 12 volts. Your car is holding power to ignition. I would check the MSD box. I have seen many of them go bad or some 12 volt hot all the time wire fused together with an ignition wire causing the car not to turn off.
My 2 cents worth
A car shuts off because of the loss of 12 volts. Your car is holding power to ignition. I would check the MSD box. I have seen many of them go bad or some 12 volt hot all the time wire fused together with an ignition wire causing the car not to turn off.
My 2 cents worth
Racer
Joined: Sep 2004
Posts: 279
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From: Bellport NY
If you have a q-jet, check to see if the ignition stop solenoid is functioning. Mine would continue to run until I pulled the coil wire. I had a similar condition on an MG. There they used what is refered to as an anti run-on valve. You may need to stop the air through the carb and starve the engine.
Just a thought.
Just a thought.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,112
From: Crossville TN
Is the engine "dieseling" after you cut the ignition? In other word, it does NOT have electrical for the ignition, but the engine chugs along on its own? If so, then you need to find a way to adjust the timing or come up with other means to close off the air from the carb. GM and other companies had to design in such provisions because of the emissions control systems and timing changes. The solenoid mentioned above was to completely shut the carb throttle plate so that it starved for air. On air conditioned cars, some had a switch which turned on the compressor clutch [when you shut off the ignition], just to put a load on the engine so that it wouldn't "diesel". Next time you shut off your car try this: if an automatic tranny, put it in drive and shut off your ignition....or, if manual, shut of car then let out the clutch to see if that kills the engine. If the engine shuts down (in either case), you engine is dieseling. You can put something mechanical on your carb to close it off when you turn the ignition off....or you can just shut it down and put a load on the engine to kill it.
Thread Starter
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Joined: Jun 2007
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From: Winston-Salem N.C.
Engine still runs fine with switch turned off, one time its shuts off fine , next five times it will not. not a "dieseling" problem.acts like the switch is not cutting off the power supply so i replaced it but did not fix the problem.
thanks,chris
thanks,chris
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Thread Starter
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Joined: Jun 2007
Posts: 58
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From: Winston-Salem N.C.
I will double check MSD box tonight but it did appear to be wired correctly , all MSD failures i have had in the past were usually the opposite problem they went dead.(learned not to weld on car with MSD box hooked up!)
thanks,chris
thanks,chris
Thread Starter
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Joined: Jun 2007
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From: Winston-Salem N.C.
Looks as if MSD box could be the problem , no fire from switch wire(pink wire) with ign. off. will try to bypass the MSD box tomorrow and see if that works. thanks for the help guys.
chris
chris
Drifting
Joined: Jan 2004
Posts: 1,991
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From: Piscataway NJ
Thread Starter
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Joined: Jun 2007
Posts: 58
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From: Winston-Salem N.C.
MSD box was the problem , put module back in dist. and rewired , shuts off fine now but now i need a good (with locking clip) factory style plug for the 12v and the tach wire . anybody know where to buy these plugs besides the junk yard? hard to find a good plug in the junk yard anymore they are all weathered and brittle ,locking clip breaks right off.
P.S. to "VettePower " i was shutting car off by disconnecting power supply to MSD box.
chris
P.S. to "VettePower " i was shutting car off by disconnecting power supply to MSD box.
chris
Melting Slicks
Joined: Dec 2006
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From: Kingston Ontario
Melting Slicks
Joined: Dec 2006
Posts: 2,669
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From: Kingston Ontario
Racer
Joined: Jun 2003
Posts: 368
Likes: 1
From: Lititz PA
I encountered the same problem with my installation of an MSD 6A box, the problem was current feeding back thru the alt/gen warning circuit to the MSD box.. I had to get a diode from radio shack (this allows elec current to flow one direction only) and install it in that circuit (at the alternator) problem solved.
Andy
Andy
Racer
Joined: Jun 2003
Posts: 368
Likes: 1
From: Lititz PA
This explains it much better that I can:
http://www.msdignition.com/1troub1.htm
Engine Run-On
If your engine continues to run even when the ignition is turned Off you are experiencing engine Run-On. This usually only occurs on older vehicles with an external voltage regulator. Because the MSD receives power directly from the battery, it does not require much current to keep the unit energized. If you are experiencing run-on, it is due to a small amount of voltage going through the charging lamp indicator and feeding the small Red wire even if the key is turned off.
Early Ford and GM: To solve the Run-On problem, a Diode is supplied with the MSD in the parts bag. By installing this Diode in-line of the wire that goes to the Charging indicator, the voltage is kept from entering the MSD. The diagram below shows the proper installation for early Ford
and GM vehicles.
Note: Diodes are used to allow voltage to flow only one way. Make sure the Diode is installed facing the proper direction.
http://www.msdignition.com/1troub1.htm
Engine Run-On
If your engine continues to run even when the ignition is turned Off you are experiencing engine Run-On. This usually only occurs on older vehicles with an external voltage regulator. Because the MSD receives power directly from the battery, it does not require much current to keep the unit energized. If you are experiencing run-on, it is due to a small amount of voltage going through the charging lamp indicator and feeding the small Red wire even if the key is turned off.
Early Ford and GM: To solve the Run-On problem, a Diode is supplied with the MSD in the parts bag. By installing this Diode in-line of the wire that goes to the Charging indicator, the voltage is kept from entering the MSD. The diagram below shows the proper installation for early Ford
and GM vehicles.
Note: Diodes are used to allow voltage to flow only one way. Make sure the Diode is installed facing the proper direction.
Racer
Joined: Dec 2003
Posts: 270
Likes: 0
From: owensboro ky
msd comes with the diode. car will not shut off with out it, on some cars.I encountered the same problem with my installation of an MSD 6A box, the problem was current feeding back thru the alt/gen warning circuit to the MSD box.. I had to get a diode from radio shack (this allows elec current to flow one direction only) and install it in that circuit (at the alternator) problem solved.
Andy
Andy