Friggin fragile ignition systems...

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kenh

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Backed the truck out of the shop yesterday and was letting it warm up a bit before taking a 70 mile jaunt. Walked out of the house 5 minutes later and it was not running. First thought was I blew ANOTHER ignition module. Pulled the cap to put my spare in and the center electrode was burnt away and the center of the cap was burned with a bunch of power deposited also. The rotor was also lookinga little rough but cleaned up OK. , I had a new cap, put that on and got a couple pops out of it. Pulled the new cap, installed the spare module and got one pop. $hit... must have fried the coil. Back to the shop for a spare junkyard coil and it runs. So off we go. On the way home it starts to misfire if you lean on the gas a little to hard so thinking the coil is not so good. I have one other so will throw that in. Only has to last until the LS swap is done so not super concerned for the moment.

I've never seen a cap burn down like that one did. It's not very old either.
 

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Orpedcrow

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Hey Zeus crisco, that’s gnarly looking.

Seems like these trucks either have consistent ignition issues or they run forever on original parts.

I had an accel coil quit with no signs of failure. Truck just shut off while cruising down the road. I put my unknown mileage original back on and haven’t had any issues.
 

L31MaxExpress

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Backed the truck out of the shop yesterday and was letting it warm up a bit before taking a 70 mile jaunt. Walked out of the house 5 minutes later and it was not running. First thought was I blew ANOTHER ignition module. Pulled the cap to put my spare in and the center electrode was burnt away and the center of the cap was burned with a bunch of power deposited also. The rotor was also lookinga little rough but cleaned up OK. , I had a new cap, put that on and got a couple pops out of it. Pulled the new cap, installed the spare module and got one pop. $hit... must have fried the coil. Back to the shop for a spare junkyard coil and it runs. So off we go. On the way home it starts to misfire if you lean on the gas a little to hard so thinking the coil is not so good. I have one other so will throw that in. Only has to last until the LS swap is done so not super concerned for the moment.

I've never seen a cap burn down like that one did. It's not very old either.
The old large caps will burn like that if you use the OEM style carbon button or forget the rubber insulating pad.

Vacuum venting the distributor base has seemed to end 99.5% of cap and rotor failures on the vehicles I have tried them on.
 

Schurkey

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If there's anything that describes the various GM HEI ignitiion systems, "fragile" is at the opposite end of the spectrum. HEIs are approximately THE most-reliable electronic ignition systems on the planet. Pickup coil wires, TBI distributor shaft magnets, and the Vortec distributor cap are the biggest problems with them. All easily solved.

If you're having repeat problems, it's because there's something wrong that hasn't been addressed. When the center button burns-out of the cap, it's almost certainly due to a failed coil wire, failed spark plug wires, and/or huge spark plug or rotor-to-cap gaps. High resistance, sky-high voltage + excess heat.

Similarly, when an ignition coil fails, it often takes the module with it. Aftermarket coils--including expensive "boutique hot-rod brands" are infamous for premature failure. Cheap (but not necessarily inexpensive) Communist crap.

When plug wires (or coil wire) fails, the excess voltage is hard on the coil. You begin to see the potential chain of events: A high-resistance coil wire (or plug wire) causes the coil to produce excess voltage; that voltage causes the coil's internal windings to short, which draws too much current from the module. The wire, the coil, and the module are all wounded, and the distributor cap, rotor, and other "downstream" components have their service life shortened, too. It's all interconnected.

Thus I grab any decent OEM ignition-system parts (coils, modules with heat-sinks, and complete distributors) when I visit a Treasure Yard. I avoid buying aftermarket ignition parts where practical. Wire-wound (Helical-wound, sometimes incorrectly called "Spiral-wound") spark plug wires tend to have greater service life than carbon-rope "stock" wires, although I question that they have better "performance". Nearly everyone selling wire-wound spark plug wires whines endlessly about how they're "low resistance" while entirely and deceptively failing to mention that they're high inductance. Either one--resistance or inductance--effectively limits spark current (amperage) and thus radio-frequency interference.
 

kenh

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Hey Zeus crisco, that’s gnarly looking.

Seems like these trucks either have consistent ignition issues or they run forever on original parts.

I had an accel coil quit with no signs of failure. Truck just shut off while cruising down the road. I put my unknown mileage original back on and haven’t had any issues.
If there's anything that describes the various GM HEI ignitiion systems, "fragile" is at the opposite end of the spectrum. HEIs are approximately THE most-reliable electronic ignition systems on the planet. Pickup coil wires, TBI distributor shaft magnets, and the Vortec distributor cap are the biggest problems with them. All easily solved.

If you're having repeat problems, it's because there's something wrong that hasn't been addressed. When the center button burns-out of the cap, it's almost certainly due to a failed coil wire, failed spark plug wires, and/or huge spark plug or rotor-to-cap gaps. High resistance, sky-high voltage + excess heat.

Similarly, when an ignition coil fails, it often takes the module with it. Aftermarket coils--including expensive "boutique hot-rod brands" are infamous for premature failure. Cheap (but not necessarily inexpensive) Communist crap.

When plug wires (or coil wire) fails, the excess voltage is hard on the coil. You begin to see the potential chain of events: A high-resistance coil wire (or plug wire) causes the coil to produce excess voltage; that voltage causes the coil's internal windings to short, which draws too much current from the module. The wire, the coil, and the module are all wounded, and the distributor cap, rotor, and other "downstream" components have their service life shortened, too. It's all interconnected.

Thus I grab any decent OEM ignition-system parts (coils, modules with heat-sinks, and complete distributors) when I visit a Treasure Yard. I avoid buying aftermarket ignition parts where practical. Wire-wound (Helical-wound, sometimes incorrectly called "Spiral-wound") spark plug wires tend to have greater service life than carbon-rope "stock" wires, although I question that they have better "performance". Nearly everyone selling wire-wound spark plug wires whines endlessly about how they're "low resistance" while entirely and deceptively failing to mention that they're high inductance. Either one--resistance or inductance--effectively limits spark current (amperage) and thus radio-frequency interference.
I was having an endless series of module failures. The previous owner had installed an Accel coil. Finially bought a junkyard coil and threw the Accel away and low and behold no more module failures. Along with the coil I brought home a distributor which was installed with the coil. In the meantime I had replaced the cap and wires with medium of the road components. NO issues for over a year till the burned cap showed up. The ignition issues with this truck have wasted more time and created more frustration than all the other issues combined. Another reason for the pending LS swap.

Ken
 

L31MaxExpress

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I was having an endless series of module failures. The previous owner had installed an Accel coil. Finially bought a junkyard coil and threw the Accel away and low and behold no more module failures. Along with the coil I brought home a distributor which was installed with the coil. In the meantime I had replaced the cap and wires with medium of the road components. NO issues for over a year till the burned cap showed up. The ignition issues with this truck have wasted more time and created more frustration than all the other issues combined. Another reason for the pending LS swap.

Ken
I had so many issues in 30K with the LS coils that I removed them and put a distributor back in. Even the factory LS powered vans have near constant coil issues. Too much heat where they are located and they burn out.
 

RichLo

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I was having an endless series of module failures. The previous owner had installed an Accel coil. Finially bought a junkyard coil and threw the Accel away and low and behold no more module failures. Along with the coil I brought home a distributor which was installed with the coil. In the meantime I had replaced the cap and wires with medium of the road components. NO issues for over a year till the burned cap showed up. The ignition issues with this truck have wasted more time and created more frustration than all the other issues combined. Another reason for the pending LS swap.

Ken

"Medium of the road components' are usually the same as cheap components with a different label and a higher profit margin.

If I am fixing something to keep and not worry about I try to find AC delco or equivalent OEM grade components. Sometimes they have a Made In USA lable on the box. A junkyard distributor could be OEM or it could be an older mystery replacement. Start fresh with top of the line components before spending bunches of money converting to LS... unless you just really want an LS.
 

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I had so many issues in 30K with the LS coils that I removed them and put a distributor back in. Even the factory LS powered vans have near constant coil issues. Too much heat where they are located and they burn out.

I don't know about that, but they pretty much last forever in truck and car use.
 

kenh

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L31MaxExpress said:


I had so many issues in 30K with the LS coils that I removed them and put a distributor back in. Even the factory LS powered vans have near constant coil issues. Too much heat where they are located and they burn out.

I'm curious how you put a distributor in a LS????? I reading your post like you had/have an LS with a distributor.

Ken
 
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