HEI ignition troubles

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UDUST81

UDUST81

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So I recently hooked up gm style hei on my duster with 440 big block due to being tired of dealing with the Mopar electronic ignition parts and dealing with old wiring as well so I included a relay to bypass a lot of the old wiring as well

When I went to start I had no spark

When I took out my test light to make sure I was getting power I happened to touch terminal "c" on the HEI module (the terminal that goes to the negative side of the coil)

When I did that all of a sudden the I heard a buzzing/whining noise from the coil or the HEI.... Not sure which one as they are mounted close to one another

To my surprise the car fires right up after doing this but if you shut it off and try again It won't fire untill you ground out the negative side of the coil or "terminal c" then it will fire right up again

Not sure what I'm doing wrong kinda stumped on this one any help is appreciated

I will try to attach photo of my wiring diagram as I'm guessing maybe something is wired wrong

Thank you!

IMG_20210603_224828.jpg
 
Make sure the two ferrules on the module are connected to ground [ usually via a heat sink ].
If this has been done, then I think it is time for a new module.

In case you are unaware, MSD make a HEI module # 83647 that gives a hotter spark & also has a built in adjustable rev limiter.
 
Bewy said:
Make sure the two ferrules on the module are connected to ground [ usually via a heat sink ].
If this has been done, then I think it is time for a new module.

In case you are unaware, MSD make a HEI module # 83647 that gives a hotter spark & also has a built in adjustable rev limiter.
Click to expand...
It is grounded via the aluminum heat sink and I also have a ground wire going from one mounting bolt to the alternator case but I can try to make sure both bolts are grounded.

Module is brand new out of the box although I know with electronic parts that doesn't always mean good
 
What I'd do:

1....De-wire the system and "hot wire" it to eliminate all car wiring possible problems. In other words connect a jumper to coil+/ HEI module and jumper direct to battery

2...Double triple check that module is actually grounded. To do that connect your jumper power and stick your voltmeter on a good ground, like the block or battery NEG post. Stick the other terminal on the module mounting holes metal grommets. There should be ZERO reading.

3...Suspect the distributor connector. Those can be problematic as there is no real power there, so a slight amount of corrosion can stop the "works. "Work" the connector in/ out several times to scrub the terminals. Since you have access to the HEI module, connect your meter to the pickup terminals at the HEI with meter on low AC volts. Spin the dist or crank engine. Pickup coil should generate about 1V AC
 
RELAY: Using a relay in the "run" circuit is not at all a bad idea, except in this case you really did not go far enough. "The usual failure" in the "run" circuit, is that voltage drop in that circuit causes the voltage regulator to see low battery voltage, and this causes it to ramp up alternator output, thus actually causing an OVER voltage situation. When you get this sorted out, you should also tie the VR /field into the relay output
 
67Dart273 said:
What I'd do:

1....De-wire the system and "hot wire" it to eliminate all car wiring possible problems. In other words connect a jumper to coil+/ HEI module and jumper direct to battery

2...Double triple check that module is actually grounded. To do that connect your jumper power and stick your voltmeter on a good ground, like the block or battery NEG post. Stick the other terminal on the module mounting holes metal grommets. There should be ZERO reading.

3...Suspect the distributor connector. Those can be problematic as there is no real power there, so a slight amount of corrosion can stop the "works. "Work" the connector in/ out several times to scrub the terminals. Since you have access to the HEI module, connect your meter to the pickup terminals at the HEI with meter on low AC volts. Spin the dist or crank engine. Pickup coil should generate about 1V AC
Click to expand...


I will try all these when I get home from work tonight thank you very much!!
 
All of the tests listed above passed

I've also replaced relay and ignition module and still the same issue

Also ran a wire for ground to battery in trunk as well just to double check grounds are good

Honestly stumped at this point
Could it have anything to do with the ignition coil even tho it runs fine when you jump the c terminal?

Does the ignition coil need to be grounded?

Thanks everyone for all the help so far... I really appreciate it. I'm not very good at electrical in the first place even tho I'm trying to learn
 
I don't know. I dislike "throwing parts" at a problem but it might be time. You don't have a spare dist you can substitute? You don't even need to install it, just connect it and finger spin the shaft

Coils do not need to be grounded. The connections are all done by the two primary terminals and the high voltage tower. Secondary (high voltage) is internally connected to the primary, so it grounds through that
 
67Dart273 said:
I don't know. I dislike "throwing parts" at a problem but it might be time. You don't have a spare dist you can substitute? You don't even need to install it, just connect it and finger spin the shaft

Coils do not need to be grounded. The connections are all done by the two primary terminals and the high voltage tower. Secondary (high voltage) is internally connected to the primary, so it grounds through that
Click to expand...

You may be right

I started this HEI conversion with the idea that it would be a cheep-ish solution to my irregular ignition problems I was having with the Mopar electronic ignition

Come to think of it the only part I didn't change out this whole time was the distributor....

I did change the pickup coil in the distributor bit not the dizzy it's self..... It's there anything else that can fail in the dizzy if it's still turning and the gap is set right for the pickup coil???

Honestly if I could just get it running consistently enough to feel confident to drive across my little town of 5000 people I'd be happy

I've been fighting this ignition issue losing interest and regaining it back and forth for two years now

Once again I want to thank you sir for all your help I don't have many people I know to turn to for these kinds of issues and I appreciate it very much!
 
I don't know. I'm beginning to wonder if some HEI modules and by that I mean different actual manufacturers OR variance in quality control------is some aren't more demanding in trigger levels (the distributor pickup) I just don't know.
 
67Dart273 said:
I don't know. I'm beginning to wonder if some HEI modules and by that I mean different actual manufacturers OR variance in quality control------is some aren't more demanding in trigger levels (the distributor pickup) I just don't know.
Click to expand...


That could be the case

Like I said I'm not very talented when it comes to electronics so pardon my ignorance when I may not seem to know too much

That's why I kind of followed the exact Module and coil slant6dan had in that post

It could be my dizzy is not compatible with the parts I selected

My real question is why does it run so well after the "c" terminal gets jumped to ground and then won't start at all until you do it again?

Obviously i can't leave it/ drive it that way but I can't explain why that makes it run
 
67Dart273 said:
I don't know. I'm beginning to wonder if some HEI modules and by that I mean different actual manufacturers OR variance in quality control------is some aren't more demanding in trigger levels (the distributor pickup) I just don't know.
Click to expand...


Yep. There is a quality issue among the manufacturers. You can sometimes see it on the distributor machine. I can’t wait to get the dyno up and running and hook my scope up to a running engine under load.
 
Btw distributor in the car is just a cheapie pro-form for an rb

Maybe it could be the cause of all my issues from the start

I'm with you I hate to parts change but it may be worth the chance as I'd like to make it to the show and shine here in town next Saturday seeing I've missed the last two
 
yellow rose said:
Yep. There is a quality issue among the manufacturers. You can sometimes see it on the distributor machine. I can’t wait to get the dyno up and running and hook my scope up to a running engine under load.
Click to expand...


Like I was saying earlier the dizzy it's the only thing that I haven't outright changed in this whole process

Maybe it could be the source of my inconsistency in the ignition circuit
 
If the upper bush in the dizzy is severely worn, the reluctor tip could touch the p/up coil & you get no spark on THAT cyl. There HAS to be an air gap for a spark to be created.
 
Tsully said:
@TrailBeast I’ve never seen an HEI conversation use a relay have you?

I don’t have one on mine.
Click to expand...

Never seen one, but there would only be one reason I wouldn’t use a relay.
It unnecessarily complicates the ignition circuit.
(Says the guy with 10 of them on his car) :D
 
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