HEI Troubleshoot - The 1947 - Present Chevrolet & GMC Truck Message Board Network

JayDubBlazer · 09-09-2008, 08:31 AM

So I am all excited to start my truck and for some reason or another I am not getting spark. I have an accel HEI and I replaced the coil during the recent rebuild. I am getting power to the coil but no spark. How do I trouble shoot the HEI. I did take the coil off last night to check the resistance (I seem to remember as that being the first step in trouble shooting) it had a resistance of 8.6 on the 20K scale. Is it common to have non-functioning coils out of the box? How do I check the module?

Any help would be appreciated, I only have about a month to get this thing on the road before it gets to cold.

**steelhorse** · 09-09-2008, 09:04 AM

Did you put the button back under the coil?Is the power going to the right terminal?

Shyguy · 09-09-2008, 09:23 AM

If you take the module to either Auto Zone or O'Reilly's they will check the module for free.

I have never had a coil bad out of the box, but anything is possible.

Make sure the coil is grounded.

Danny

68gmsee · 09-09-2008, 09:31 AM

Here's the Auto Zone trouble shooting site for HEI. May help you.

Scroll down to the bottom and click on a pic to see the larger print.

http://www.autozone.com/az/cds/en_us...rInfoPages.htm

JayDubBlazer · 09-09-2008, 10:42 AM

Quote:

Originally Posted by steelhorse

Did you put the button back under the coil?Is the power going to the right terminal?

I tore it apart and the spring is in there with the button and I had it going to the red wire.

Luvlegs · 09-09-2008, 01:47 PM

full 12volts right? I know it seems like a rookie thing but going by the KISS standard, had to ask. Changed the resistance type wire that supplied the points with ~9v over to a good 12volts source right?

Possible you put in a new wiring harness that had the points type set up?

JayDubBlazer · 09-09-2008, 02:59 PM

Quote:

Originally Posted by Luvlegs

full 12volts right? I know it seems like a rookie thing but going by the KISS standard, had to ask. Changed the resistance type wire that supplied the points with ~9v over to a good 12volts source right?

Possible you put in a new wiring harness that had the points type set up?

Somebody mentioned that at work, I'm going to check that when I get home. It is a new wiring harness. It does get the full 12 volts with the assy on.

Andy4639 · 09-09-2008, 03:06 PM

It has to get full 12 volts with key trying to crank the motor any drop in the wire will cause a no crank systom. Make sure it's 12 volts no matter what position the key is in.

piecesparts · 09-09-2008, 04:46 PM

There is always something that slips up and kicks your butt on these things. I had one that had everything but spark and it turned out to be the pick-up coil UNDER the ignition module. this would require the removal of the dizzy shaft from the housing to change out. The first thing I would look at is the module in the dizzy and BE SURE to use dielectric grease.

JimKshortstep4x4 · 09-09-2008, 07:47 PM

While dielectric grease is good to use on electrical connections it is not recommended that it be used for heat transfer applications. A better grease for use between the module and the distributor housing is a heat transfer grease which is a white grease made specifically for heat transfer. Usually new modules come with the grease.

Heat transfer grease is also referred to as Heat Sink Compound.

Jim

kelsfine69 · 09-09-2008, 09:31 PM

Quote:

Originally Posted by Andy4639

It has to get full 12 volts with key trying to crank the motor any drop in the wire will cause a no crank systom. Make sure it's 12 volts no matter what position the key is in.

X2

seen it happen.....had 12v in run but start was 0v

JayDubBlazer · 09-10-2008, 07:26 AM

Quote:

Originally Posted by Andy4639

It has to get full 12 volts with key trying to crank the motor any drop in the wire will cause a no crank systom. Make sure it's 12 volts no matter what position the key is in.

It has 12 Vdc with acc on, and around 11 Vdc when starting. I also read the painless wire instructions and it said if using a HEI wire the pink wire directly to the coil. I have pulled the module out and took it to Advanced Autoparts. Though it is an Accel module they tested it and it appeared to be non operational. I have purchased another one, but in the process to see if I can check it our myself, just to double check.

JayDubBlazer · 09-15-2008, 01:51 PM

I have put in the new module and still am not getting any spark. I have 12v through the coil and 12v going into the modulel. I have also tested the distributor and it is properly grounded. I am starting to get at wits end, I am sure it has to be something simple.

70rs/ss · 09-15-2008, 02:01 PM

IS the 12v during cranking? The reason I ask is that I had it set to acc and it only got 12v on crank, but when i let the key go into run position it had no voltage?

JayDubBlazer · 09-15-2008, 02:10 PM

Quote:

Originally Posted by 70rs/ss

IS the 12v during cranking? The reason I ask is that I had it set to acc and it only got 12v on crank, but when i let the key go into run position it had no voltage?

I am getting about 11 vdc when cranking and 12.8 vdc when acc is on

70rs/ss · 09-15-2008, 02:32 PM

A pict of the cap and coil might help, but it is dead on right and not 180 out? No spark, as in you have a wire off and spin it over with a plug in it and grounded with no spark?? If so then there is an issue with the module or coil. There is an article in this months Car Craft that mentions there are two coil types for GM hei and they are not interchangeable, maybe you have one of these? Picts might help us to trouble shoot for you??

**CPNE** · 09-15-2008, 02:47 PM

HEI Pickup coil could be bad. Been there, done that.

JayDubBlazer · 09-15-2008, 05:35 PM

It is an Accel aftermarket HEI model number 59107. Ill see if I can snap a picture. And no I am not getting any spark at the plug. The distributor is aligned with TDC, we took the valve cover off.

piecesparts · 09-15-2008, 09:11 PM

Quote:

Originally Posted by CPNE

HEI Pickup coil could be bad. Been there, done that.

Agree on the pickup coil, had one do the same thing and I replaced everything---finally this is what solved the problem.

70GMCer · 09-16-2008, 07:16 AM

Just a thought.....do you have the 12 volt wire plugged into the 12 volt side of the dist. cap, and not into the tachometer side?

JayDubBlazer · 09-16-2008, 07:23 AM

Quote:

Originally Posted by 70GMCer

Just a thought.....do you have the 12 volt wire plugged into the 12 volt side of the dist. cap, and not into the tachometer side?

Yep, and I have 12 vdc going through the coil. I am going to call the Accell tech support this morning and see if they can give me a hand. I did have one thought last night. I replaced the cap and rotor before I put the dizzy back in. I was wondering because I didn't use an Accel brand cap and rotor that I might not be getting any connectivity between the cap and rotor. One more thing to write off the list.

Sorry I wasn't able to get a picture, I will try tonight.

Thanks for all the help

kulturekat · 09-16-2008, 10:05 AM

i was having the same problem justa fewnights ago i replaced just about everything on that hei. what it came down to was somehow one of the wires leading into the cap that hookes to the c b and grd had came loose that hooks to a bolt inside the cap.

also i agree to check on the pickup coil. i would go all the way back through all your connectiuons and look to see if everything is eithe rhooked up correctly or to make sure you dont have any cuts or anything. if all that checks out then id check the pickup coil. i only speak from experience i had a lot of good guys on here help and point me in the right direction.

hootz · 09-16-2008, 10:27 AM

Check the pickup coil with an ohm meter. You should see between 500 and 1500 ohms when measuring from wire to wire (unplugged from the module) . Be sure to wiggle the wires while testing as the pickup coil moves with the advance and the wires can break but the outside insulation remains intact. You should not measure any resistance at all from either wire to ground. Also take a good look at the rotor. They are bad about allowing current to ground out to the shaft through the rotor itself. Take the rotor off and look at it from the bottom in the middle where it contacts the shaft. If you see any purple discoloration suspect a bad rotor.

dznucks · 09-16-2008, 10:27 AM

i have had a similar situation. the ground strap (bent metal strip) inside the cap had broken and i didn't catch it for a few days.

mrein3 · 09-16-2008, 12:41 PM

Quote:

Originally Posted by piecesparts

Agree on the pickup coil, had one do the same thing and I replaced everything---finally this is what solved the problem.

Back when I was still working in the shop I saw a lot of HEIs come in with one of the pickup coil wires broke. If you look at it it looks fine. Take your little screwdriver and put some side pressure on both of the pickup wires. If one is broke you won't have any spark.

09-09-2008, 08:31 AM	#1
JayDubBlazer go cyclones Join Date: Jun 2003 Location: Ames, IA Posts: 1,885	HEI Troubleshoot So I am all excited to start my truck and for some reason or another I am not getting spark. I have an accel HEI and I replaced the coil during the recent rebuild. I am getting power to the coil but no spark. How do I trouble shoot the HEI. I did take the coil off last night to check the resistance (I seem to remember as that being the first step in trouble shooting) it had a resistance of 8.6 on the 20K scale. Is it common to have non-functioning coils out of the box? How do I check the module? Any help would be appreciated, I only have about a month to get this thing on the road before it gets to cold. __________________ Wes PROJECT OLE GREEN 1972 Blazer 4X4 350/700R4 2017 Silverado LT

09-09-2008, 09:04 AM	#2
steelhorse Senior Member Join Date: Apr 2008 Location: Franklinton NC Posts: 1,309	Re: HEI Troubleshoot Did you put the button back under the coil?Is the power going to the right terminal?

09-09-2008, 09:23 AM	#3
Shyguy Junior Member Join Date: Dec 2006 Location: Southeast Missouri Posts: 2,436	Re: HEI Troubleshoot If you take the module to either Auto Zone or O'Reilly's they will check the module for free. I have never had a coil bad out of the box, but anything is possible. Make sure the coil is grounded. Danny __________________ '67 Chevy C-20 short stepper - build complete, 454/SM-465. '75 C-30 Single Cab DRW-350 small block/NP-435. '77 GMC-6500 Dump Truck, 427 Tall Deck. '92 GMC K-3500 Duallie, 454/4L80E.

09-09-2008, 09:31 AM	#4
68gmsee Active Member Join Date: Jul 2007 Location: Centrally located between Houston, Austin and Waco. BCS area. Posts: 7,947	Re: HEI Troubleshoot Here's the Auto Zone trouble shooting site for HEI. May help you. Scroll down to the bottom and click on a pic to see the larger print. http://www.autozone.com/az/cds/en_us...rInfoPages.htm

09-09-2008, 01:47 PM	#6
Luvlegs Registered User Join Date: Sep 2005 Location: Smith Mountain Lake Virginia Posts: 1,537	Re: HEI Troubleshoot full 12volts right? I know it seems like a rookie thing but going by the KISS standard, had to ask. Changed the resistance type wire that supplied the points with ~9v over to a good 12volts source right? Possible you put in a new wiring harness that had the points type set up? __________________ "A cat will almost always blink when hit between the eyes with a ball peen hammer" (you don't always have to state the obvious) Wear your PPE! You can eat with false teeth but you can't see with a false eye. 1959 Studebaker Silverhawk 350/400 1972 C10 L6 3OTT 2005 F350 - Built - whew! Last edited by Luvlegs; 09-09-2008 at 01:50 PM.

09-09-2008, 03:06 PM	#8
Andy4639 Old member Join Date: Jan 2002 Location: Liberty, & Garden City S.C. , U.S. Posts: 19,945	Re: HEI Troubleshoot It has to get full 12 volts with key trying to crank the motor any drop in the wire will cause a no crank systom. Make sure it's 12 volts no matter what position the key is in. __________________ 1971 LWB Custom, 6.0LS & 4L80E, Speedhut.com GPS speedometer & gauges with A/C. 20" Boss 338's Grey wheels 4 wheel disc brakes. My Driver Seeing the USA in a 71 Upstate SC GM Truck Club 2013,14 and 2016 Hot Rod Pour Tour http://upstategmtrucks.com/ Get out and drive the truck this summer and have some fun! It sucks not being able to hear! LWB trucks rule, if you don't think so measure your SWB! After talking to tech support at Air Lift I have found out that the kit I need is 60811. Per the measurements I gave them. Ride height of truck inside spring and inside diameter of springs.

09-09-2008, 04:46 PM	#9
piecesparts Parts and more parts Join Date: Nov 2003 Location: Lebo, Kansas (middle of nowhere Posts: 6,821	Re: HEI Troubleshoot There is always something that slips up and kicks your butt on these things. I had one that had everything but spark and it turned out to be the pick-up coil UNDER the ignition module. this would require the removal of the dizzy shaft from the housing to change out. The first thing I would look at is the module in the dizzy and BE SURE to use dielectric grease.

09-09-2008, 07:47 PM	#10
JimKshortstep4x4 Senior Member Join Date: Jul 2001 Location: Muskegon,MI,USA Posts: 6,026	Re: HEI Troubleshoot While dielectric grease is good to use on electrical connections it is not recommended that it be used for heat transfer applications. A better grease for use between the module and the distributor housing is a heat transfer grease which is a white grease made specifically for heat transfer. Usually new modules come with the grease. Heat transfer grease is also referred to as Heat Sink Compound. Jim __________________ 1971 Shortbox step side 4x4, 350 sbc, 3:07 rear end 1965 Impala SS 400 sbc, Muncie rock crusher 1966 Impala SS 396 bbc, TH 400 1969 El Camino, 350 sbc, TH 350 1971 Snowplow built on a Blazer frame 1972 GMC Short bed, stepside, TH 400, 427 BBC

09-15-2008, 01:51 PM	#13
JayDubBlazer go cyclones Join Date: Jun 2003 Location: Ames, IA Posts: 1,885	Re: HEI Troubleshoot I have put in the new module and still am not getting any spark. I have 12v through the coil and 12v going into the modulel. I have also tested the distributor and it is properly grounded. I am starting to get at wits end, I am sure it has to be something simple. __________________ Wes PROJECT OLE GREEN 1972 Blazer 4X4 350/700R4 2017 Silverado LT

09-15-2008, 02:01 PM	#14
70rs/ss Registered User Join Date: Dec 2004 Location: Northern AZ Posts: 7,271	Re: HEI Troubleshoot IS the 12v during cranking? The reason I ask is that I had it set to acc and it only got 12v on crank, but when i let the key go into run position it had no voltage?

09-15-2008, 02:32 PM	#16
70rs/ss Registered User Join Date: Dec 2004 Location: Northern AZ Posts: 7,271	Re: HEI Troubleshoot A pict of the cap and coil might help, but it is dead on right and not 180 out? No spark, as in you have a wire off and spin it over with a plug in it and grounded with no spark?? If so then there is an issue with the module or coil. There is an article in this months Car Craft that mentions there are two coil types for GM hei and they are not interchangeable, maybe you have one of these? Picts might help us to trouble shoot for you??

09-15-2008, 02:47 PM	#17
CPNE Resident Curmudgeon Join Date: Dec 1999 Location: NH Posts: 6,664	Re: HEI Troubleshoot HEI Pickup coil could be bad. Been there, done that. Attached Images __________________ Currently on or near the homestead: 67 Chevy SWB 2WD stepside 350/3 on tree (Pat's) 67 GMC SWB 2WD Fleet 402/auto (Brian's under construction) 67 Chevy 3/4 ton 2WD 402/auto (Business Hauler) 67 Chevy 1 ton dually 2WD 396/4 speed (Former business hauler, Needs TLC) 68 Chevy 1/2 ton Suburban 2WD 250 six/3 on tree (Brian's Needs TLC) 70 Chevy 3/4 ton 4WD 350/4 speed (Pat's - Disguised as a 68 GMC) 71 Chevy SWB stepside (Crushed by tree - parts donor) 72 Chevy 3/4 ton 4WD (Parts donor) 72 Chevy 3/4 ton 4WD Suburban (Parts Donor) 72 GMC 3/4 ton 4WD 292 six/4 speed (Mine - Disguised as a 67 GMC) 81 GMC 4WD Dually Dump Body 350/4 speed (Business Hauler) 82 Camaro Z/28 355/Super T-10 (Pat's toy) 93 Caprice 9C1 (Brian's Cop Car) 02 Toyota Camry (Reliable but a souless steel and plastic hulk) 2011 2SS RS Camaro M6 Factory Hurst Shifter Maybe I need to sell some of this crap Yet another Bozo with a sawz-all

09-15-2008, 05:35 PM	#18
JayDubBlazer go cyclones Join Date: Jun 2003 Location: Ames, IA Posts: 1,885	Re: HEI Troubleshoot It is an Accel aftermarket HEI model number 59107. Ill see if I can snap a picture. And no I am not getting any spark at the plug. The distributor is aligned with TDC, we took the valve cover off. __________________ Wes PROJECT OLE GREEN 1972 Blazer 4X4 350/700R4 2017 Silverado LT

09-16-2008, 07:16 AM	#20
70GMCer Senior Member Join Date: Apr 2005 Location: Joppa, Maryland Posts: 4,408	Re: HEI Troubleshoot Just a thought.....do you have the 12 volt wire plugged into the 12 volt side of the dist. cap, and not into the tachometer side? __________________ 1997 GMC Sierra Ext 1965 Mustang

09-16-2008, 10:05 AM	#22
kulturekat Registered User Join Date: Dec 2007 Location: stillwater, oklahoma Posts: 566	Re: HEI Troubleshoot i was having the same problem justa fewnights ago i replaced just about everything on that hei. what it came down to was somehow one of the wires leading into the cap that hookes to the c b and grd had came loose that hooks to a bolt inside the cap. also i agree to check on the pickup coil. i would go all the way back through all your connectiuons and look to see if everything is eithe rhooked up correctly or to make sure you dont have any cuts or anything. if all that checks out then id check the pickup coil. i only speak from experience i had a lot of good guys on here help and point me in the right direction.



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09-16-2008, 10:27 AM	#23
hootz Registered User Join Date: Feb 2008 Location: Rogers, AR Posts: 15	Re: HEI Troubleshoot Check the pickup coil with an ohm meter. You should see between 500 and 1500 ohms when measuring from wire to wire (unplugged from the module) . Be sure to wiggle the wires while testing as the pickup coil moves with the advance and the wires can break but the outside insulation remains intact. You should not measure any resistance at all from either wire to ground. Also take a good look at the rotor. They are bad about allowing current to ground out to the shaft through the rotor itself. Take the rotor off and look at it from the bottom in the middle where it contacts the shaft. If you see any purple discoloration suspect a bad rotor. __________________ Never say Never!!

09-16-2008, 10:27 AM	#24
dznucks Registered User Join Date: Feb 2006 Location: Smyrna, Ga Posts: 1,647	Re: HEI Troubleshoot i have had a similar situation. the ground strap (bent metal strip) inside the cap had broken and i didn't catch it for a few days.

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