[EricTopless68 Camaro]

I need GM HEI help before I go nuts! I have a coil in cap-style HEI on my 68 Camaro 327. The distributor is a ProForm unit, and has about 3,500 miles on it.

I have been chasing a miss and carb calibration, and I finally got the carb right. I ordered an MSD HEI upgrade kit (cap, rotor, coil, and module) and MSD wires to address the miss. Well, I found the miss (one of the boots on my old Blue Maxes was melted), but decided to install the rest of the upgrade anyway. I put it all in, cranked it, and have no spark. I have a full 12 V to the hot side of the coil. I checked continuity on the coil, and had none (and infinite resistance), so I sent the coil back and had Summit send me a new one. In the meantime, I got an OE replacement coil, checked continuity on it (it was good), but couldn't install it because it did not come with a rotor bushing and I didn't feel like installing the old one.

So, today I go to put in the new coil, checking continuity first. It had none! Then I checked the new OE replacement coil, and couldn't get continuity there either! I decided to put everything together using the MSD coil anyway, and lo and behold, no spark.

So here are my questions for the gurus:

1) Are there diagnostics I can do to confirm a bad coil, other than the continuity/resistance check?

2) Are these coils just a bad design? I had one go bad on the car once during winter storage, but I can't believe this new OE replacement coil went tango uniform sitting in the box on my workbench.

3) Any suggestions? Please?? I'm begging here!

Thanks!
Eric

[Jmark]

Been a while since I did any HEI testing, mine just keeps going and going! LOL

But I found a Mallory trouble shooting site. Clicky here!

[Heavybreather]

Unless you actually have a "coil tester" your pretty much left with the resistance tests. You should have very low resistance usually 0 between the TACH terminal and the BAT terminal, that's your primary. You should have between 6K and 30K ohms between the BAT terminal and the rotor button (secondary). You should also have that same reading between the rotor button and the TACH terminal. There should be NO continuity between any terminals and ground. Be sure every thing is disconnected when doing these. I thought I'd write down the steps just in case. It's pretty easy to probe the wrong terminal and chase a spark in the wrong direction. Good luck

[Edge-Net]

Ok 1st thing I love the GM HEI, It keeps on going and going. I think your main problem is the GM module. I have 2 spares. Too bad you don't live in the Toronto area. I would have let you try one. Next best thing I can do is sell you one for $20.00. I always keep a spare. The coil and the rest of the items in the dis. never go defective.

[RedSled]

Just a sanity check here. Did you test the battery in your multimeter??

[Forsaken502]

if you know someone with a GM HEI igintion system you could ask them to switch in your coil to see if it works.

[TooMany2count]

did you put the ground STRAP (fixed the spelling ) back on for the coil????..joe

[Walker]

Hey toomanytocount what exactly is a ground SPRAP? Is it similar to an air SPRAP? lol

[TooMany2count]

Originally posted by Walker
Hey toomanytocount what exactly is a ground SPRAP? Is it similar to an air SPRAP? lol

damn these big fingers it should read "STRAP"

[propaniac]

thats what she said

[EricTopless68 Camaro]

Edge... thanks for the offer, but I have the OE module I can put back in. The module that is in it now is the MSD unit that came with the upgrade kit, MSD #8364.

I'll try some of the diagnostics on that Mallory page, and then if that fails I will just put all the OE pieces back in and try it. If it works, I guess I'll send the MSD stuff back to Summit. I have to admit, the MSD module scares me a little, since it isn't an exact drop in for the OE-style. You have to pull the capcitor and all out for the OE unit, then the MSD unit drops in (only has pins on one end). I don't know if the MSD unit would last longer than the OE-type, but because I have had those go bad, I too carry an extra module at all times.

Thanks for listening and offering help. I'm just frustrated, because I have so little time to work on the car these days (3 year old boy and 2 month old girl keep me busy), and I want stuff to work the first time.

Eric

[Edge-Net]

Eric

I stick to the GM HEI, I have used those suckers in all gm products and I have never been let down. The aftermarket stuff in most cases is of poor quailty In MSD's case your engine would have to be redlined at above 6,000 rpm to take any advange of it's performace. If your engine is redlined at 5,500 then the GM dist. is the only way to go. Here at the local bone yard they sell the complete HEI for $60.00. Let us know on how you make out

[EricTopless68 Camaro]

I just wanted to come back and say that I found my trouble. The MSD module was bad (as was the coil that came in the same shipment...the box from Summit didn't LOOK abused). I put my OE module back in, and she runs great now.

Just wanted to say thanks for the help!
Eric

[Edge-Net]

Originally posted by EricTopless68 Camaro
I just wanted to come back and say that I found my trouble. The MSD module was bad (as was the coil that came in the same shipment...the box from Summit didn't LOOK abused). I put my OE module back in, and she runs great now.

Just wanted to say thanks for the help!
Eric

You are welcome. I am an electrical Guru