module testing - The 1947 - Present Chevrolet & GMC Truck Message Board Network

tx71smallblock · 08-25-2007, 05:35 PM

i think i spelled it right?
is there a way to test an HEI module without going to the autoparts store?
wile im at it, i tryed to start the truck today and had no spark could the module be the only problem? the distributor, cap, rotor, wires and plugs are all new the only old part is the module.

BurnoutNova · 08-25-2007, 06:51 PM

the only correct way to diag an ignition module is to test eveything else... seems dumb, but those pos testers at the auto parts store just test continuity. sometimes modules will only act up at certain temps, and the parts store cannot recreate the same environment and bad modules will test good somtimes

tx71smallblock · 08-25-2007, 06:59 PM

well i took it anyway and he said it was good and that it maybe the pickup coil. im not good at the electric part of the motor so i really dont know what that is.

A.P. · 08-25-2007, 09:04 PM

The pick up coil is on top of your distributor. Unbolt it and check continuity on the primary and secondary with an ohm meter.

http://67-72chevytrucks.com/vboard/s...ht=distributor

ChevLoRay · 08-25-2007, 10:07 PM

What I found in my HEI problem was the wire to the reluctor in the distributor was broken. It would make contact and when letting off of the gas, the vacuum advance would move and the wire connection would be broken. I fixed that problem with an Accel HEI replacement distributor. No problems since that time.

I can fix the old HEI with a new part from NAPA, but the whole distributor would need to be rebuilt...bushings, etc. It has a new 4-pin module in it and a nearly new Vette vacuum advance.

So, it may not be your module, as I found out....after replacing the distributor.

When you replace the module, if that is what it takes, be sure to use the dilectric grease in mounting the new part....that's what takes the heat away from the module. Without the grease, it just won't last.

67ChevyRedneck · 08-25-2007, 10:34 PM

Also, check your dizzy cap to be sure that you have the metal ground that goes from the cap to the coil! I've seen it missing quite a few times. There should be two grounds in the cap. I fried a coil and module because I was missing one.

If your pretty sure it's your coil and module, I think coils are like $16 bucks and modules are about the same. Be sure to use dielectric grease on everything when you reinstall.

**VetteVet** · 08-26-2007, 12:04 AM

If you care?
http://www.rustpuppy.org/ignition2/Ignition%202b.htm

08-25-2007, 05:35 PM	#1
tx71smallblock Registered User Join Date: Jun 2007 Location: Georgetown , TX Posts: 166	module testing i think i spelled it right? is there a way to test an HEI module without going to the autoparts store? wile im at it, i tryed to start the truck today and had no spark could the module be the only problem? the distributor, cap, rotor, wires and plugs are all new the only old part is the module. __________________ 70 Chevy C-10 short step 250/3 on the tree Owned: 71 longbed Cheyenne 70 swb

08-25-2007, 06:51 PM	#2
BurnoutNova Registered User Join Date: Mar 2004 Location: CA Posts: 2,057	Re: module testing the only correct way to diag an ignition module is to test eveything else... seems dumb, but those pos testers at the auto parts store just test continuity. sometimes modules will only act up at certain temps, and the parts store cannot recreate the same environment and bad modules will test good somtimes

08-25-2007, 06:59 PM	#3
tx71smallblock Registered User Join Date: Jun 2007 Location: Georgetown , TX Posts: 166	Re: module testing well i took it anyway and he said it was good and that it maybe the pickup coil. im not good at the electric part of the motor so i really dont know what that is. __________________ 70 Chevy C-10 short step 250/3 on the tree Owned: 71 longbed Cheyenne 70 swb

08-25-2007, 09:04 PM	#4
A.P. Black 72 Chevy Join Date: May 2002 Location: Los Angeles, California Posts: 662	Re: module testing The pick up coil is on top of your distributor. Unbolt it and check continuity on the primary and secondary with an ohm meter. http://67-72chevytrucks.com/vboard/s...ht=distributor __________________ 72 Chevy, SWB, 350engine, TH400

08-25-2007, 10:07 PM	#5
ChevLoRay Old Skool Club Join Date: Jun 2001 Location: Benton, AR "The Heart of Arkansas" Posts: 10,880	Re: module testing What I found in my HEI problem was the wire to the reluctor in the distributor was broken. It would make contact and when letting off of the gas, the vacuum advance would move and the wire connection would be broken. I fixed that problem with an Accel HEI replacement distributor. No problems since that time. I can fix the old HEI with a new part from NAPA, but the whole distributor would need to be rebuilt...bushings, etc. It has a new 4-pin module in it and a nearly new Vette vacuum advance. So, it may not be your module, as I found out....after replacing the distributor. When you replace the module, if that is what it takes, be sure to use the dilectric grease in mounting the new part....that's what takes the heat away from the module. Without the grease, it just won't last. __________________ Member Nr. 2770 '96 GMC Sportside; 4.3/SLT - Daily driven....constantly needs washed. '69 C-10 SWB; 350/TH400 - in limbo The older I get, the better I was.

08-25-2007, 10:34 PM	#6
67ChevyRedneck Hittin E-Z Street on Mud Tires Join Date: Nov 2004 Location: Greenville, SC Posts: 23,090	Re: module testing Also, check your dizzy cap to be sure that you have the metal ground that goes from the cap to the coil! I've seen it missing quite a few times. There should be two grounds in the cap. I fried a coil and module because I was missing one. If your pretty sure it's your coil and module, I think coils are like $16 bucks and modules are about the same. Be sure to use dielectric grease on everything when you reinstall. __________________ Jesse James 1967 C10 SWB Stepside: 350/700R4/3.73 1965 Ford Mustang: 289/T5-5spd/3.25 Trac-Loc 1968 Pontiac Firebird: Project Fire Chicken! 2015 Silverado Double Cab 5.3L Z71 2001 Jeep Wrangler Sport 4.0L 5spd 2020 Chevrolet Equinox Premium 2.0L Turbo 2011 Mustang V6 ~ Wife's ride American Born, Country by the Grace of God 1967 CST Shop Truck Rebuild! My 1967 C-10 Build Thread My Vintage Air A/C Install Project "On a Dime" Trying my hand at Home Renovation! 1965 Mustang Modifications!

08-26-2007, 12:04 AM	#7
VetteVet Msgt USAF Ret Join Date: Jan 2005 Location: Kalamazoo, Michigan Posts: 8,718	Re: module testing If you care? http://www.rustpuppy.org/ignition2/Ignition%202b.htm __________________ VetteVet metallic green 67 stepside 74 corvette convertible 1965 Harley sportster 1995 Harley wide glide Growing old is hell, but it beats the alternative.

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