HEI Ignition gurus Help!

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7dart0

7dart0

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So I have a 70 dart with 360 magnum it runs fantastic with an 8 pin HEI. When I replaced my distributor with a new factory style I retimed the car and noticed when I revved the engine up to 3-3500 rpm it was advancing another 10 degrees. This is strange since I have a locked out distributor with an FBO plate.
Since I heard of other people having that 10 degree advance with an 8 pin, I figured I'd change to 4 pin.
Well i wired it up and it starts beautiful but wont rev over 1800 rpm. It breaks up like theres a rev limiter. It was a cheap 4 pin through Advance auto parts, part #CBE4. I tried another one because I thought I got a dud, but it does the same thing. I'll add pics of the diagram I used and of my setup.

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Just checking- I’m running same 4 pin with great results.
12vdc to HEI coil not stock chrysler 9vdc coil? Right?
 
Yes I'm using the gm coil in the picture. It works fine with the 8 pin, and breaks up with 4 pin
 
Flip the wires from the distributor around and i bet itll work. Had the same problen with mine and a very common problem/fix.
 
Sorry did not see picture of coil- right in front of me lol!
I agree to flip pick up module wires.
 
I did flip the wires, it runs even worse and barely starts.
 
Hot wire the module to "known" 12V and make DARN sure it is grounded. If that does not work, it sounds like a just-plain-defective-out-of-the-box module. Remember, "New" does not mean "functional"
 
You did put the dielectric grease between the heat sink and the module right?
Also did you double check the Airgap between the reluctor and the pick up inside the distributor? Brass gauge only and I think it’s .017”- .020”. Double check a service manual.
 
I did put the grease on the module. This is easy to wire I'm not sure why it's not working. The 8 pin works fine with the distributor and the coil.
As soon as I swap my wires to the 4 pin module it starts up fine but breaks up around 1500 rpm. It doesnt even make sense. Lol.
 
Syleng1 said:
You did put the dielectric grease between the heat sink and the module right?
Also did you double check the Airgap between the reluctor and the pick up inside the distributor? Brass gauge only and I think it’s .017”- .020”. Double check a service manual.
Click to expand...

No it's more like .008". Inches not metric. Make certain the reluctor is not striking the pickup. And "work" the connector in/ out several times, there is no real current in there, and it does not take much corrosion to stop the signal.
 
It's not the distributor or the coil, when I switch back to my 8 pin module everything is fine. Is it just a crappy 4 pin module from advance auto.
 
7dart0 said:
It's not the distributor or the coil, when I switch back to my 8 pin module everything is fine. Is it just a crappy 4 pin module from advance auto.
Click to expand...
sounds like it, go to NAPA
 
Most autoparts have a tester for ignition modules.
And dont forget the spare for the glove box.
 
Well I got the napa brand module, still doing the same. Starts fine but rev it up and misses around 1800 rpm. I know the 8 pin is fine but I really dont want that extra 10 degree advance in the module.

Should I try swapping the coil pos and neg wires?

Thanks
 
weird, just to make sure, you are mounting the new ones like you do the old one, heat sink, paste same location, right? need to get rid of all the variables
 
Only change was new distributor?
try a jumper ground from Phillips screw on distributor exterior to ground for module.
 
Last edited:
No the only change was going from an 8 pin hei to a 4 pin hei.
 
Well it has to be SOMETHING

Maybe the dist is on the ragged edge for trigger

Maybe the dist CONNECTOR is dirty corroded, this is a known problem Work the connector in/ out several times. Have you actually checked reluctor clearance?

I asked you about grounding have you actually CHECKED it? With engine running, probe the two eyelets on the module to battery ground and see if there is any voltage. Should be ZERO

Check supply voltage. Both coil + and module should be "same as battery" WHEN RUNNING

I've found coil to be non-critical on these. Many cllaim you must have some special E-coil, but I was running the stock old Mopar coil, no ballast resistor

You might monitor timing while diddling engine RPM.
 
67Dart273 said:
Well it has to be SOMETHING

Maybe the dist is on the ragged edge for trigger

Maybe the dist CONNECTOR is dirty corroded, this is a known problem Work the connector in/ out several times. Have you actually checked reluctor clearance?

I asked you about grounding have you actually CHECKED it? With engine running, probe the two eyelets on the module to battery ground and see if there is any voltage. Should be ZERO

Check supply voltage. Both coil + and module should be "same as battery" WHEN RUNNING

I've found coil to be non-critical on these. Many cllaim you must have some special E-coil, but I was running the stock old Mopar coil, no ballast resistor

You might monitor timing while diddling engine RPM.
Click to expand...

I will make those checks in the morning. But why on earth would the 8 pin be fine but the dumber 4 pin not work right? It makes no sense.

Thanks everyone so far for suggestions.
 
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