how to test a hei coil - The 1947 - Present Chevrolet & GMC Truck Message Board Network

mtdave2 · 08-03-2005, 06:05 PM

anyone have a link for the testing of a coil? i think mine is dead and i have forgot how to test it.

cdowns · 08-03-2005, 07:47 PM

you can go to most autoparts stores and they
'll test them for free

355 · 08-04-2005, 08:54 AM

Pull the whole dist. out. Put a wire, like tie wire, from one plug wire post to the next and just loop them together in series, but don't connct #1 to #8 and leave a 1 to 1 1/2 foot tail on your wire. Lay the dist. shaft on your front grill support for a ground, hook up a 12v hot wire to the dist. and locate the wire tail close to your grill. Spin the gear and you should see a hard spark from the tail wire every time the rotor passes a plug terminal. Did any of that make sense?

Canadian72GMC · 08-04-2005, 09:08 AM

Or, remove coil, .5 ohms from primary negative to primary positive, and 8,000 to 12,000 ohms from the center button(secondary) to either the primary positive or negative terminal depending on the year of the distributor.

mtdave2 · 08-04-2005, 11:00 AM

thats what i needed that canadian72gmc. i tried the part stores lol, what a waste of skin those guys are. they looked at me like i was crazy.

gregbr · 08-06-2005, 10:39 AM

Sorta agree with canadian72gmc....with the coil REMOVED, reading between coil primary leads (red & white or yellow) should be .5 ohms approx. Checking the secondary side...reading from the button to the metal coil frame or black wire (depending on the coil brand) you should have 6-10,000 ohms. Factory coil has a black lead that is grounded to the metal frame, 50,000 volt super coil does not. With the coil installed and the ignition module wires plugged up, you read the secondary to the primary like canadian72gmc said. Just went thru this myself, secondary side died. New factory type was $18 at AutoZone. Greg

08-03-2005, 07:47 PM	#2
cdowns Senior Member Join Date: Jan 2003 Location: daytonabeach Posts: 22,956	you can go to most autoparts stores and they 'll test them for free __________________ 71c-10 350/2004r/4:11 lowered3/4 longbed/dead by hurricane MEANING OF DEATH::::: SOMEBODY ELSE GETS YOUR STUFF DONT BELIEVE EVERYTHING YOU THINK TAKE MY ADVISE;I DON'T USE IT ANYWAY

08-04-2005, 08:54 AM	#3
355 Registered User Join Date: May 2005 Location: South Mississippi Posts: 81	Pull the whole dist. out. Put a wire, like tie wire, from one plug wire post to the next and just loop them together in series, but don't connct #1 to #8 and leave a 1 to 1 1/2 foot tail on your wire. Lay the dist. shaft on your front grill support for a ground, hook up a 12v hot wire to the dist. and locate the wire tail close to your grill. Spin the gear and you should see a hard spark from the tail wire every time the rotor passes a plug terminal. Did any of that make sense? __________________ 1969 C10 Long Step,355,700r4w/lockup, HEI,Weiand,750 Performer,1.6 rockers,Camel Humps,Comp 262Extreme,Hedman,2 1/2"pipes, tele/tilt,SunRoof,ps,Disc pb,ac,Cragar,eaton,Corvette style roll pan, Bowtie louvered tail gate,lowered 2/2.

08-04-2005, 11:00 AM	#5
mtdave2 newly minted old timer Join Date: Dec 1999 Location: Hudson WI Posts: 3,508	thats what i needed that canadian72gmc. i tried the part stores lol, what a waste of skin those guys are. they looked at me like i was crazy. __________________ ____________________________________________ 72 c20 longhorn 65k org miles and counting! 69 k10 Suburban Last edited by mtdave2; 08-04-2005 at 11:00 AM.

08-06-2005, 10:39 AM	#6
gregbr Senoir Member Join Date: Mar 2002 Location: Rock Hill, SC USA Posts: 1,214	Sorta agree with canadian72gmc....with the coil REMOVED, reading between coil primary leads (red & white or yellow) should be .5 ohms approx. Checking the secondary side...reading from the button to the metal coil frame or black wire (depending on the coil brand) you should have 6-10,000 ohms. Factory coil has a black lead that is grounded to the metal frame, 50,000 volt super coil does not. With the coil installed and the ignition module wires plugged up, you read the secondary to the primary like canadian72gmc said. Just went thru this myself, secondary side died. New factory type was $18 at AutoZone. Greg __________________ 67 Chevy, Small back glass, Factory 4WD, Factory Shortbed, Factory V8, Lifted 4" 70 GMC Sierra Grande, Factory Shortbed, Factory 402/400 turbo, Super Custom Interior. Numbers matching with SPID & Build Sheet. 68K Original Miles. Restored 2010 70 GMC Restoration Pictures http://67-72chevytrucks.com/gallery/...00&ppuser=4424

08-03-2005, 06:05 PM	#1
mtdave2 newly minted old timer Join Date: Dec 1999 Location: Hudson WI Posts: 3,508	how to test a hei coil anyone have a link for the testing of a coil? i think mine is dead and i have forgot how to test it. __________________ ____________________________________________ 72 c20 longhorn 65k org miles and counting! 69 k10 Suburban

08-04-2005, 09:08 AM	#4
Canadian72GMC Registered User Join Date: Mar 2005 Location: north battleford, sk Posts: 30	Or, remove coil, .5 ohms from primary negative to primary positive, and 8,000 to 12,000 ohms from the center button(secondary) to either the primary positive or negative terminal depending on the year of the distributor.



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