4 Pin GM HEI module will not work!!!

[Madfaber]

Looking for help on this, I have a 1978 fj40, did not have coil or ignition module when I got it so I am trying to do the 4 pin GM ignition module and standard 12 v coil set up.
The info from this thread
Bypass Toyota Ignition and Coil

I used the parts listed in the thread
Ignition Module from a 1979 GM truck with a 350 CI engine Autozone P/N DR100
Coil from a 1972 Chevrolet k10 4wd truck with a 350 CI engine Autozone P/N C819
Connected as directed.

B = +12v Power
C = Ground to Coil
W = Signal wire from distributor
G = Signal wire from distributor

I have seen several threads on this forum of people using this set up on Fj40 using the 1978 fully electronic dizzy (same as whats in my rig).

I set it up got no spark. I have 12v to HEI 4 pin module, 12 v at the coil. So I thought the elctronic pickup coil in the dizzy was bad. Put in a brand new pickup in, still no spark. Verified air gap was set correct for the dizzy pickup. Tried a different coil, brand new MSD blaster 2 , still no spark. Tried a different 4 pin module. No spark. Ran all new wires between the module and dizzy. It seems to me that some how ignition module is not getting the signal from the distributor to ground out terminal C on the 4 pin module and cause the spark plug to spark. But I do not know why, I have a ground going directly from the module to the negative on the battery so I know its gettin a good ground. Is anyone running this set up ??? i have replaced everything twice and I am totally stumped, please help!

 

[honk]

And you assume that the module is good because why?

I used to run an HEI distributor. What I carried in my glove box was spare module(s). Delco-Remy preferable, IMO.

 

[SuperBuickGuy]

What honk said. I'm on number 4 on my '40. A friend just had his go smokey. I've been doing car stuff most of my life (nearly 50 now) and I've never had such trouble with a part. Test the module, don't even think of using a cheap module.

 

[Madfaber]

Superbuickguy, honk. I assume its good because i have used two different ones brand new out of he box with the same result, no spark, two new coils, no spark, new pickup coil, no spark

 

[SuperBuickGuy]

You can actually test them (which came as a surprise to me). It's probably fine, but we're both suggesting that without testing; you don't know if it's working.
how are you triggering the module? HEI modules can be a bear if the Hall effect rotor/magnets aren't right (not enough of a difference to trigger, or not in phase)

from that link

It ended up being that my distributor was so corroded inside that it could not make contacts. I ended up dismantling it and sanding all the corrosion off the steel parts, i put it back together and its been running fine ever since. So i ditched a perfectly good ignitor and coil for nothing. But i am still glad i set it up like this, so much simpler and stupid cheap to fix if something fails.​

 

[Landpimp]

May I suggest at some point trying to find a fj60 dizzy, coil/ignitor and dented side cover (81-87 fj40 or 60) it's a bolt on OEM dizzy that just works perfect.

 

[Madfaber]

You can actually test them (which came as a surprise to me). It's probably fine, but we're both suggesting that without testing; you don't know if it's working.
how are you triggering the module? HEI modules can be a bear if the Hall effect rotor/magnets aren't right (not enough of a difference to trigger, or not in phase)

from that link

It ended up being that my distributor was so corroded inside that it could not make contacts. I ended up dismantling it and sanding all the corrosion off the steel parts, i put it back together and its been running fine ever since. So i ditched a perfectly good ignitor and coil for nothing. But i am still glad i set it up like this, so much simpler and stupid cheap to fix if something fails.​

SuperBuickGuy ,
I read that two and cleaned up the reluctor and bought a brand new pick up coil, is there something else that needs to be cleaned in the distributor that would effect the signal?

 

[SuperBuickGuy]

Here's what I would check if I were there:
1) the module
2) the ground between the module and the distributor base (this is uber important because if the ground is faulty, the chip wouldn't get the difference in signal from the rotation of the magnet and pickup)
3) the cap for corrosion
4) that there is a good ground between the battery/motor/frame/chassis. You cannot have enough grounds IMO
5) that the points of the trigger wheel line up with the point on the rotor.

Layman's explanation on Hall effect. The closer the steel is to the magnet the more energy that transfers between those two wires. Its signal looks like a sine wave. basically the signal goes from like 1v to 5v - when it's at 5v, that triggers the switch - which, when the switch is open, allows the coil to charge. The chip wouldn't get that difference in signal if the ground was faulty between the two thus keeping the switch open and not allowing discharge. The ground is as important as the positive side of the equation. Going to your situation, you should have very low resistance between the distributor's housing and the module (aka chip). you also could test the magnet by simply doing a continuity test between the two wires that come from the magnet/rotor wheel.

There is something else that bugs me a bit - V6 and V8 modules are different. I have no idea the difference, but one of those 'last things I'd do' is go pull a module from a 4.3 and try that.... but that'd be a last-step.... along with being sure whatever the Toyota uses for it's Hall-effect wheel is similar to the GM one used (number of degrees between the points).

 

[DougAustinTx]

I agree with everything SuperBuickGuy said except for: "There is something else that bugs me a bit - V6 and V8 modules are different. I have no idea the difference, but one of those 'last things I'd do' is go pull a module from a 4.3 and try that.... but that'd be a last-step.... along with being sure whatever the Toyota uses for it's Hall-effect wheel is similar to the GM one used (number of degrees between the points)."

I use a V8 HEI module in my 6 cylinder Triumph TR6 (and I still use the points to trigger it) and I will be putting the same module in a 1972 Honda 600 coupe that only has 2 cylinders. The modules don't care how many cylinders you have. You should make sure there is plenty of aluminum heatsink under the module (with the heat transfer paste) if you want it to live.

 

[SuperBuickGuy]

different part numbers - at minimum there's the difference.
also
the hall effect would be different with 6 points rather then 8

you're using anecdotal evidence - which is fine - but not as accurate as what I just said.... and lord knows, on here it has to be perfect otherwise the world will end.