HEI Install Problems

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zsn0w

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Trying to test install an HEI module and coil into my car... Having a lot of trouble and I don't know why. Thought maybe the coil was bad. Switched back to the standard coil. I know it can't run that way long but I wanted to test it since it can start on 12v without a problem with the canister coil normally and I know it was running with the normal coil 4 days ago.
So, I wired the positive of the coil to the + of the HEI module and also directly to the battery for testing. Wired the - of the coil to the C terminal on the module. Wired the two reluctor wires in. Grounded the module right to battery ground. removed the original wires from the coil and unplugged the factory ECU so everything should be isolated. As soon as the starter turns, it should start sparking right? No spark... I have 12 volts at the coil. I tested continuity back to the module from both coil sides and it's good. I even took a second distributor I had laying around and wired it up to the battery out of the car and to the module with no coil and spun it by hand. Saw a little jump on the multimeter, so it appears the module is reading and sending something at least... Any suggestions are appreciated. Not sure what I'm doing wrong here. Tested everything separately and it all seems good, but together it just won't work.
 
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Maybe this paragraph explains the problem. Not sure.
 
I use the stock mopar coil just fine, no ballast. If you powered it up AT ALL without the module mounted flat to a heat sink you likely destroyed the module. Was the distributor you are using running on another ignition before this?

If you have ANYTHING else connected to coil NEG remove it. Might be shorting tach wire or bad radio cap, etc

Also some modern coils are tricky to hook up. Some have 4 terminals and are not wired as you might think
 
Also, on some of those modules the aluminum screw hole liners have to make contact with the back side aluminum plate to actually ground.
If the module isn't mounted down during your testing try it.
 
The distributor I'm using in the car is the same one that was running fine with the original ignition. Right now I just have it ziptied to a BIG cpu heatsink, but it's on there pretty good and flat and there was even a little thermal paste left on the heat sink from before. Nothing else connected to the negative on the coil. Just the C terminal on the module. Nothing on the positive besides 12V from battery and + terminal on module. Maybe all the quickly made crimp connections are adding up and it's too much resistance... Wouldn't think that would matter though.

For the ground I took a screw and screwed both a wire directly to the battery ground and the module G pin wire into one of the screw hole liners. There's continuity from the G pin to the screw hole liners, so they're all the same ground. I'm also getting 12V between the other screw hole liner and battery +, so it's grounding as far as I can tell.

Maybe I'll go to the junkyard and grab another module tomorrow and see if that's my problem... It WAS pulsing while bench testing it and spinning a distributor by hand, but my multimeter isn't high enough resolution to actually show the exact voltage being put out.

I am correct in that the stock mopar ECU should be unplugged correct? The wiring over there shouldn't be connected with anything at this point anyway since the old reluctor connections and coil connections are disconnected.
 
67Dart273 said:
Ziptied................I bet you fried it.
Click to expand...
Is there a way to test it? Like I said, I spun a distributor by hand that I had hooked up to it and was getting pulses out the negative side, so some amount of opening and closing is going on inside it still. I don't know how to know if it is doing it correctly, though.
 
zsn0w said:
I am correct in that the stock mopar ECU should be unplugged correct? The wiring over there shouldn't be connected with anything at this point anyway since the old reluctor connections and coil connections are disconnected.
Click to expand...

You are correct, though it shouldn't matter if the new ECU has it's own power supplied, and is the only thing connected to the distributor.
Something is up because these modules are generally really easy to hook up.
 
Got a couple more modules the other day. First one I pulled at the junkyard was an aftermarket one and I don't know if I trust it so I pulled another and figured I should just buy both to mess with them if I need to. Haven't had time to wire them in. I'm going to set one up sometime this weekend hopefully and see if it won't work. If it doesn't, I'll post up pictures of my setup to see if I'm just missing something obvious or what. Hoping it was just a faulty module. Going to have to figure out a good way to mount the module on the heatsink, though. Even though I used zip ties before, it was on there pretty good with a little thermal paste, flat on the big aluminum finned chunk. I'm going to make sure that it is on there as good as possible this time though so I don't have to worry that I could've fried it.
 
dart_68 said:
Thank you. A lot of people are using the 8 PIN and don't seem to be having problems. However, I am having some issues and I'm wondering if this could be the problem.
Click to expand...
Do you have a thread? If not start one many here are very willing to help.
8 pin from what I’ve read seems to be preferred, more tolerant of voltage variations and I like the connectors a little better. First thing most will ask is check for full voltage and check or try switching wires to distributor (polarity).
Also need a good ground, one other thing is electronic noise be sure wires from module to distributor are twisted and routed away from any other wires best you can. Or you can also add shielding.
 
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