Guess what....HEI ran BUT..... - The 1947 - Present Chevrolet & GMC Truck Message Board Network

PitterPats72 · 05-29-2002, 09:49 PM

Guess what guys???? I changed the spark polug wiring to the configuration of a point dist and GUESS what:...it ran BUT also I couldn't get the dang thing to turn off... pulled the key and everything. I piulled a plug wire and then the battery cables (both) and it kept on running. Eventually I had to pull the T connector on the front of the carb. That was the weirdest thing, especially when I had the keys in my had and it's still running.

Any ideas now about the spark plug wiring????

Thanks again,
pat

Longhorn Man · 05-29-2002, 10:04 PM

Leave the wires as they are. Who cares if it isn't wired like a later model vehicle?
Your run on is becouse the wire you plugged into the dizzy is hot at all times. You'l have to do the under dash boogie again and plug it into one of the IGN-UNFUSED terminals. If it is in one already, your harness is messed up.

__________________

lux hauler · 05-29-2002, 10:10 PM

if it's running with the switch off, couldn't she pull the wire from the fuse block to see if she has constant power? (it should die when she pulls the wire right?)

BigJackDaddy · 05-31-2002, 01:46 PM

Your engine Run-on is not unique if your truck has the alternator "idiot" light. The purpose of the light is to prevent the backflow if electricity in the alternator excite circuit. If the light bulb is omitted from the conversion, the engine will continue to run even after the key is turned off due to the backflow of electricity from the P1 terminal on the alternator to the "ACCESSORY" post on the Terminal Block, and then out to the coil.

By hooking to the radio circuit, you my have bypassed the indicator light, if so equipped. Since you got it running (Congratulations, by the way), you may want to re-connect your wiring to the proper "ign" circuit to see if that doesn't cure the problem.

Mike C · 05-31-2002, 03:06 PM

It just sounds like you have the +12v wire to a terminal that is not switched. Make sure you are on the spade terminal marked IGN. While it is common for an MSD to run on with feedback votage from a warning light, it is not possible for such small voltage to trigger an HEI since the only wire is the 12v wire. The MSD is hooked with 10ga wire to a constant 12v source and the activation voltage is miniscule which is why it runs on with feedback voltage.

05-29-2002, 09:49 PM	#1
PitterPats72 Registered User Join Date: Oct 2001 Location: Indianapolis, IN Posts: 145	Guess what....HEI ran BUT..... Guess what guys???? I changed the spark polug wiring to the configuration of a point dist and GUESS what:...it ran BUT also I couldn't get the dang thing to turn off... pulled the key and everything. I piulled a plug wire and then the battery cables (both) and it kept on running. Eventually I had to pull the T connector on the front of the carb. That was the weirdest thing, especially when I had the keys in my had and it's still running. Any ideas now about the spark plug wiring???? Thanks again, pat __________________ 72 Chevy Custom 10 Deluxe (78K mi.) 95 Nissan Maxima (195K mi.) 73 VW Beetle (owned since 78; 96K miles) Engine rebuild by me done! 73 VW Super Beetle -New to me- Bought from original owner! 84 Honda Nighthawk (2500 mi.) I know too much foreign stuff; I've owned American too and they lasted just as long.

05-29-2002, 10:10 PM	#3
lux hauler Psycho-billy Member Join Date: Jul 2001 Location: about 40 miles west of Cleveland, Ohio Posts: 2,591	if it's running with the switch off, couldn't she pull the wire from the fuse block to see if she has constant power? (it should die when she pulls the wire right?) __________________ '72 C-10 350 w/Lunati Voodoo cam (207/213, .437/.454), Performer intake, 625 Road Demon Jr. and Hooker headers. Support your community, support yourself. Buy local, buy American (or Canadian).

05-31-2002, 01:46 PM	#4
BigJackDaddy Registered User Join Date: Sep 2000 Location: Falcon, CO Posts: 194	Your engine Run-on is not unique if your truck has the alternator "idiot" light. The purpose of the light is to prevent the backflow if electricity in the alternator excite circuit. If the light bulb is omitted from the conversion, the engine will continue to run even after the key is turned off due to the backflow of electricity from the P1 terminal on the alternator to the "ACCESSORY" post on the Terminal Block, and then out to the coil. By hooking to the radio circuit, you my have bypassed the indicator light, if so equipped. Since you got it running (Congratulations, by the way), you may want to re-connect your wiring to the proper "ign" circuit to see if that doesn't cure the problem. __________________ ColoradoMelons.com

05-31-2002, 03:06 PM	#5
Mike C Registered User Join Date: Dec 1999 Location: Austin, TX, USA Posts: 7,723	It just sounds like you have the +12v wire to a terminal that is not switched. Make sure you are on the spade terminal marked IGN. While it is common for an MSD to run on with feedback votage from a warning light, it is not possible for such small voltage to trigger an HEI since the only wire is the 12v wire. The MSD is hooked with 10ga wire to a constant 12v source and the activation voltage is miniscule which is why it runs on with feedback voltage. __________________ 44 Willys MB 52 M38A1 64 Corvette Coupe 68 Camaro 'vert LT1 & TH700 69 Z/28 355 12.6's @110 69 Chevy Short Step 4 1/2"/7" drop 72 Jimmy 4WD 4spd 4" & 35's 02 GMC 2500HD 4x4 Duramax

05-29-2002, 10:04 PM	#2
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	Leave the wires as they are. Who cares if it isn't wired like a later model vehicle? Your run on is becouse the wire you plugged into the dizzy is hot at all times. You'l have to do the under dash boogie again and plug it into one of the IGN-UNFUSED terminals. If it is in one already, your harness is messed up. __________________



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