86 C10 HEI issues - The 1947 - Present Chevrolet & GMC Truck Message Board Network

jricharc · 01-19-2017, 11:00 AM

I recently bought an '86 C10 that has a 350 from a late 70's Camaro in it. Right before i bought it the previous owner said that he put a new cap and rotor on and it was running fine. I pulled the carb off over Christmas week to rebuild it, I put it back on earlier this week and it wouldn't fire. I had a buddy help me troubleshoot it and it's not getting spark so I think the coil and the control module took a crap. I am wondering if this wasn't what may have cause the previous owner to replace the cap and rotor. Is there anything I should look for that may be causing these issues?

I am going to buy a new HEI tune-up kit from Summit to replace the entire top of the distributor but I wanted to see if there could be something causing these going bad before I waste that money and burn that one up.

**VetteVet** · 01-19-2017, 02:41 PM

This will probably start a debate but we've had them before anyway I'd give it a try for the price.
http://www.ebay.com/itm/SBC-BBC-CHEV...item4d521427b8

Had you heard the engine run before you bought it?

jricharc · 01-19-2017, 04:26 PM

Quote:

Originally Posted by VetteVet

This will probably start a debate but we've had them before anyway I'd give it a try for the price.
http://www.ebay.com/itm/SBC-BBC-CHEV...item4d521427b8

Had you heard the engine run before you bought it?

Yes, it ran fine other than a little rough which was my reasoning for the carb rebuild. My buddy that is a mechanic seems to think the coil went bad causing the control module to fry as well. So I plan on replacing those I just wanted to make sure there aren't any usual culprits causing bad coils that I should check for beforehand.

**VetteVet** · 01-19-2017, 05:15 PM

Have you checked the wire at the distributor BAT terminal for 12 volts with the key on. You may Have lost the power to it. You could run a wire from the battery positive to there and then check for spark.
The old style external voltage regulators were suspected of voltage surges to the system causing the modules in the distributor to burn out. I can't swear to that since the PO of my truck never had a problem with his.

jricharc · 01-19-2017, 05:32 PM

Yes we had power with the key on and we checked for continuity between the module and got nothing so that's why I think they both died.

**Wrenchbender Ret** · 01-19-2017, 05:51 PM

I have found most failures especially intermediate ones are caused by the pickup coil going bad. This moves every time the vacuum advance works & flexes the wires. They break inside the insulation & cause failure.

jricharc · 01-19-2017, 05:58 PM

Quote:

Originally Posted by Wrenchbender Ret

I have found most failures especially intermediate ones are caused by the pickup coil going bad. This moves every time the vacuum advance works & flexes the wires. They break inside the insulation & cause failure.

I will check that and make sure it's not shot too, thanks!

starterman99 · 01-19-2017, 07:49 PM

If the distributor cap was replaced make sure the ground strap was put in the new cap to the coil frame. they get overlooked sometimes.

**VetteVet** · 01-20-2017, 12:00 AM

Quote:

Originally Posted by starterman99

If the distributor cap was replaced make sure the ground strap was put in the new cap to the coil frame. they get overlooked sometimes.

Yeah I forgot about that.

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*gmachinz* · 01-20-2017, 09:05 AM

What...? A Chinese built distributor with a part missing?!? That doesn't happen often does it? lol

**Wrenchbender Ret** · 01-20-2017, 12:50 PM

Quote:

Originally Posted by starterman99

If the distributor cap was replaced make sure the ground strap was put in the new cap to the coil frame. they get overlooked sometimes.

Yes. I have run into that also. The ground term has to be transferred from the old cap to the new one. If left out it will cause all sorts of component failure.

jricharc · 01-26-2017, 11:33 AM

Ok so the ground strap was not installed w/ the new cap. I bought a "used" complete distributor off craigslist and was told it was from a running car, the Control module was a brand new high performance version from summit, the coil is an Accel high output model.

So I added the ground strap to the cap that was on the truck along with the new module and coil, I am still not getting any spark so is it possible that something else in the distributor went bad? I guess I will pull the entire old unit and put in the new one I got and see if that works.

**MikeB** · 01-26-2017, 11:41 AM

Hate to see you buy another one and it not work.

Here are some troubleshooting guides:

http://chevythunder.com/hei_troubles...ge_2_coil_.htm

http://www.autozone.com/repairguides...00c15280083b2c

jricharc · 01-26-2017, 01:01 PM

Quote:

Originally Posted by MikeB

Hate to see you buy another one and it not work.

Here are some troubleshooting guides:

http://chevythunder.com/hei_troubles...ge_2_coil_.htm

http://www.autozone.com/repairguides...00c15280083b2c

Thanks, I have a funny feeling its the pickup coil. I will check that and see what the meter says.

01-19-2017, 11:00 AM	#1
jricharc Registered User Join Date: Jun 2016 Location: Manassas, VA Posts: 112	86 C10 HEI issues I recently bought an '86 C10 that has a 350 from a late 70's Camaro in it. Right before i bought it the previous owner said that he put a new cap and rotor on and it was running fine. I pulled the carb off over Christmas week to rebuild it, I put it back on earlier this week and it wouldn't fire. I had a buddy help me troubleshoot it and it's not getting spark so I think the coil and the control module took a crap. I am wondering if this wasn't what may have cause the previous owner to replace the cap and rotor. Is there anything I should look for that may be causing these issues? I am going to buy a new HEI tune-up kit from Summit to replace the entire top of the distributor but I wanted to see if there could be something causing these going bad before I waste that money and burn that one up. __________________ 1986 C10 LWB 350 1970 C10 LWB 350 - Sold

01-19-2017, 02:41 PM	#2
VetteVet Msgt USAF Ret Join Date: Jan 2005 Location: Kalamazoo, Michigan Posts: 8,703	Re: 86 C10 HEI issues This will probably start a debate but we've had them before anyway I'd give it a try for the price. http://www.ebay.com/itm/SBC-BBC-CHEV...item4d521427b8 Had you heard the engine run before you bought it? __________________ VetteVet metallic green 67 stepside 74 corvette convertible 1965 Harley sportster 1995 Harley wide glide Growing old is hell, but it beats the alternative.

01-19-2017, 05:15 PM	#4
VetteVet Msgt USAF Ret Join Date: Jan 2005 Location: Kalamazoo, Michigan Posts: 8,703	Re: 86 C10 HEI issues Have you checked the wire at the distributor BAT terminal for 12 volts with the key on. You may Have lost the power to it. You could run a wire from the battery positive to there and then check for spark. The old style external voltage regulators were suspected of voltage surges to the system causing the modules in the distributor to burn out. I can't swear to that since the PO of my truck never had a problem with his. __________________ VetteVet metallic green 67 stepside 74 corvette convertible 1965 Harley sportster 1995 Harley wide glide Growing old is hell, but it beats the alternative.

01-19-2017, 05:32 PM	#5
jricharc Registered User Join Date: Jun 2016 Location: Manassas, VA Posts: 112	Re: 86 C10 HEI issues Yes we had power with the key on and we checked for continuity between the module and got nothing so that's why I think they both died. __________________ 1986 C10 LWB 350 1970 C10 LWB 350 - Sold

01-19-2017, 05:51 PM	#6
Wrenchbender Ret Registered User Join Date: Oct 2005 Location: Overland Park, Ks. Posts: 5,190	Re: 86 C10 HEI issues I have found most failures especially intermediate ones are caused by the pickup coil going bad. This moves every time the vacuum advance works & flexes the wires. They break inside the insulation & cause failure.

01-19-2017, 07:49 PM	#8
starterman99 Registered User Join Date: Jun 2008 Location: santa maria,ca. Posts: 312	Re: 86 C10 HEI issues If the distributor cap was replaced make sure the ground strap was put in the new cap to the coil frame. they get overlooked sometimes. __________________ 1957 3100 1950 5 window

01-20-2017, 09:05 AM	#10
gmachinz Account Suspended Join Date: Jun 2011 Location: Des Moines, IA. Posts: 4,143	Re: 86 C10 HEI issues What...? A Chinese built distributor with a part missing?!? That doesn't happen often does it? lol

01-26-2017, 11:33 AM	#12
jricharc Registered User Join Date: Jun 2016 Location: Manassas, VA Posts: 112	Re: 86 C10 HEI issues Ok so the ground strap was not installed w/ the new cap. I bought a "used" complete distributor off craigslist and was told it was from a running car, the Control module was a brand new high performance version from summit, the coil is an Accel high output model. So I added the ground strap to the cap that was on the truck along with the new module and coil, I am still not getting any spark so is it possible that something else in the distributor went bad? I guess I will pull the entire old unit and put in the new one I got and see if that works. __________________ 1986 C10 LWB 350 1970 C10 LWB 350 - Sold

01-26-2017, 11:41 AM	#13
MikeB Senior Member Join Date: Jul 2000 Location: North Texas Posts: 3,423	Re: 86 C10 HEI issues Hate to see you buy another one and it not work. Here are some troubleshooting guides: http://chevythunder.com/hei_troubles...ge_2_coil_.htm http://www.autozone.com/repairguides...00c15280083b2c __________________ Mike 1969 C10 LWB -- owned for 34 years. 350/TH350, 3.08 posi, 1st Gen Vintage Air, AAW wiring harness, 5-lug conversion, 1985 spindles and brakes. 1982 C10 SWB -- sold 1981 C10 Silverado LWB -- sold, but wish I still had it! 1969 C10 (not the current one) that I bought in the early 1980s. Paid $1200; sold for $1500 a few years later. Just a hint at the appreciation that was coming. Retired as a factory automation products salesman. Worked part-time over the years for an engine builder and a classic car repair shop. Member here for 23 years! This is the very first car/truck Internet forum I joined. I still used a dial-up modem back then!



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