Slant 6 HEI problems

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gilberttitan08

Mexican Hillbilly!!!
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Hey guys, just did an HEI conversion (standard bluestreak ignition coil FD478 and standard bluestreak module LX-301) on my slant 6 68 barracuda, I seem to have a weak spark after I've used a spark plug tester (weak orange spark) but a strong orange spark coming from coil. Do you guys recommend any type of spark plugs wires, I am at the moment running new OEM spark plug wires, would that be the problem? or perhaps the contact on the rotor is to far for arc contact? Or just a bad coil? Got a relay operating my HEI, constant 12v going out to my relay from alternator post then to my coil and a good strong switched 12v operating the relay coil, Car seems to run strong for about 5 min, then stumbles and dies. Starts up again, then after a while stumbles and dies. Has really good throttle response. Car has super six and dual dutra duals, if it helps.
 
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Could be a faulty component (where'd you get the distributor?), a faulty connection, inadequate module ground, insufficient power to the module and coil—did you put in a relay?—could be cruddy cap and rotor (read this whole thread), could be cruddy spark plug wires. Get good plug wires from Magnecor.
 
Hey guys, just did an HEI conversion (standard bluestreak ignition coil FD478 and standard bluestreak module LX-301) on my slant 6 68 barracuda, I seem to have a weak spark after I've used a spark plug tester (weak orange spark) but a strong orange spark coming from coil. Do you guys recommend any type of spark plugs wires, I am at the moment running new OEM spark plug wires, would that be the problem? or perhaps the contact on the rotor is to far for arc contact? Or just a bad coil? Got a relay operating my HEI, constant 12v going out to my relay from alternator post then to my coil and a good strong switched 12v operating the relay coil, Car seems to run strong for about 5 min, then stumbles and dies. Starts up again, then after a while stumbles and dies. Has really good throttle response. Car has super six and dual dutra duals, if it helps.
Just to be clear, this spark checking is right after the vehicle stops running &/or restarts, or is this the spark quality cold before the initial drive? The spark should be bright &
blue with maybe a tinge of orange. What are You using to test the spark? Is the car on the choke for the 5min., how long will it run just sitting idling to warm-up?
 
Just to be clear, this spark checking is right after the vehicle stops running &/or restarts, or is this the spark quality cold before the initial drive? The spark should be bright &
blue with maybe a tinge of orange. What are You using to test the spark? Is the car on the choke for the 5min., how long will it run just sitting idling to warm-up?
I experienced similar symptoms right after finishing an install. When I reversed the two wires that come from the distributor and all was well. I reversed them again and the engine ran poorly. I switched the wires back again and the engine ran well. I think it may have something to do with a sine wave trying to efficiently run the HEI module that is looking for a square wave. Don’t know for sure that i’m correct on this, just guessing.
Jerry in Denver
 
Just to be clear, this spark checking is right after the vehicle stops running &/or restarts, or is this the spark quality cold before the initial drive? The spark should be bright &
blue with maybe a tinge of orange. What are You using to test the spark? Is the car on the choke for the 5min., how long will it run just sitting idling to warm-up?
the spark check was both, checked it this morning, before start up, weak. Yesterday it ran amazing, very response, yes it does have choke, but bogged and died after 10 minutes of idling. Then I'd restart it, it'll run them slowly bog out and die. I used my spark plug tester to check for spark, was getting a very weak spark, when I test the wire straight off the coil, it gets a big orange/ whitish spark. But off the spark plug wire, very faint spark that slowly decipates.
 
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Pickup coil wires wrong way round as in post № 5 certainly worth checking, but runs amazing but breaks down as it warms up usually means a component is getting hot and bothered. Could be the coil, could be the pickup coil in the distributor, could be the module. How did you mount your ignition module? Add that to the other questions not yet answered in post № 3 of this thread.
 
the spark check was both, checked it this morning, before start up, weak. Yesterday it ran amazing, very response, yes it does have choke, but bogged and died after 10 minutes of idling. Then I'd restart it, it'll run them slowly bog out and die. I used my spark plug tester to check for spark, was getting a very weak spark, when I test the wire straight off the coil, it gets a big orange/ whitish spark. But off the spark plug wire, very faint spark that slowly decipates.
"Bogging & dying" sounds like running out of fuel vs misfiring or suddenly shutting off, which is usually what failing ign. components do. What condition is the tank in, new
or ?? Make sure the tank vent is clear & allowing fresh air into the tank as the pump removes fuel, if the tank is aged, rust fines may be getting picked up and clogging the
sock. After the engine stops, the fines can wash/fall off the pick-up and allow the pump to re-prime/fill the carb..only to starve-out again.
 
I experienced similar symptoms right after finishing an install. When I reversed the two wires that come from the distributor and all was well. I reversed them again and the engine ran poorly. I switched the wires back again and the engine ran well. I think it may have something to do with a sine wave trying to efficiently run the HEI module that is looking for a square wave. Don’t know for sure that i’m correct on this, just guessing.
Jerry in Denver
Very possibly, I haven't run HEI off of a Mopar pick-up, easy enough to change/check....
 
"Bogging & dying" sounds like running out of fuel vs misfiring or suddenly shutting off, which is usually what failing ign. components do. What condition is the tank in, new
or ?? Make sure the tank vent is clear & allowing fresh air into the tank as the pump removes fuel, if the tank is aged, rust fines may be getting picked up and clogging the
sock. After the engine stops, the fines can wash/fall off the pick-up and allow the pump to re-prime/fill the carb..only to starve-out again.
Car has a good used tank, took it in for cleaning and tank has is full of gas and vent line is clear. The 2 barrel carb was rebuilt and when I open up the throttle, there's 2 strong squirts of gas.
 
Will the car re-start immediately after pumping the carb twice & die, or does it just crank? I'm assuming the carb isn't flooding as You didn't mention fuel smell/leakage.
I'm also assuming this is a Carter BBD w/o a hot-idle compensator port. Is the EGR valve simply blocked off? Have You checked the timing at start-up to verify the
setting, and recheck it while cranking to see if it has changed or dropped out once it stalls? If it's failing like clockwork, I'd be sitting there with that timing light the whole
time watching for exactly what goes down the moment it starts taking a dump. The reason for the first question is the fuel level can drop below proper operating require-
ments, but still have enough to supply the accel-pump bore for a couple squirts. If the carb has the cold idle enrichment valve, is it hooked up, & if so to what? Small 3
screw diaphragm out the back near the air horn.
 
It certainly sounds like the spark is getting weakened through the distributor. OP, measure the resistance through all of the spark plug wires and coils wires. A few thousand ohms is fairly normal for most wires; it will be higher for longer wires. Anything near or over 10k ohms ought to be tossed.

Look under the cap and see where the rotor is pointing when it fires, to see if it is pretty close to the spark tower contacts on the inside. And measure the distance from the center of the rotor to the tip and make the same measurement on the diameter of the contacts on the spark towers. Clean and dry the inside of the distributor cap and look for any carbon tracks or trails. Read the links in post #3. Is this the same cap you were using before the HEI?
 
It certainly sounds like the spark is getting weakened through the distributor. OP, measure the resistance through all of the spark plug wires and coils wires. A few thousand ohms is fairly normal for most wires; it will be higher for longer wires. Anything near or over 10k ohms ought to be tossed.

Look under the cap and see where the rotor is pointing when it fires, to see if it is pretty close to the spark tower contacts on the inside. And measure the distance from the center of the rotor to the tip and make the same measurement on the diameter of the contacts on the spark towers. Clean and dry the inside of the distributor cap and look for any carbon tracks or trails. Read the links in post #3. Is this the same cap you were using before the HEI?
No, cap and rotor are NOS, figured the new cheap caps and rotors wouldn't be up for the task. The wires are fairly new. I'll have to check for resistance.
 
No, cap and rotor are NOS, figured the new cheap caps and rotors wouldn't be up for the task. The wires are fairly new. I'll have to check for resistance.
Roger.... still would not hurt to check the rotor alignment and gap in case the wrong NOS part got in there. Something is really eating up your spark and there are only a few places it could be.
 
If you have a spare cap, drill a hole in it and shine a timing light to see where the rotor tip is relative to the #1 tower when it sparks. This checks "rotor phasing". Search for the Crane XR700 manual for a description, or youtube videos. Some Mopar reluctor wheels have phasing issues. Forgot the details, but Rick Ehrenberg sells a custom reluctor on ebay to fix that. If you have the pickup leads reversed, it will spark when the rotor is between 2 towers, which will definitely make it run funny. HEI works best with an e-core coil, which you can buy cheap on ebay or get a junkyard one for a Magnum 5.2 or 5.9L engine to stay Mopar.
 
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