[68lemans462]

Need some help here guys I'm about at my wits end. Engine is a 455 with KRE 290 heads and other associated goodies. The HEI was rebuilt by "suntuned" many moons ago, it works great. I'm using a stock cap/coil, and have used assorted HEI modules. I've been through at least 4-5 modules over the past 5 years. Basically, things work great until one day the car wont start. Replace module and problem solved.

I recently installed an MSD module with a rev limiter, as I thought the root cause may be the crappy replacement modules and I wanted the stealth rev limiter capability. Today - my MSD module bit the dust. The engine was sputtering, etc and would just not run. Swapped in a "GM" module and engine fired right up.

I have read that a faulty coil can cause this. Since I'm running a stock unit likely from checker/autozone, I'm wondering if this could be at fault. Otherwise, I'm stumped. Engine is grounded well, 12V to the coil, etc..... Thoughts?

[Bill Hanlon]

Do you have heat sink grease under the module?

[chipster]

Ground strap in place?

[Sun Tuned]

Check the grounding of the deal first. Those metal straps are ok but i much prefer the ring terminaled wire version of that for a grounding strap. I've used the metal type and they work ok but I have come to like the wire version of that deal much better.

The coil may not be bad yet, but likely it is dying and taking modules with it as it goes.

Dont just look to see the grounds are in place but wouldnt hurt to remove them and lightly sand the terminal connections and recoat with some dielectric silicone to slow future corrosion and absolutely insure a solid connection.

Curious, you had any welding done lately on the vehicle?

[Half-Inch Stud]

Does your car battery drain down after sitting a week?

[PONTIAC DUDE]

Have seen it before when the cap doesn't have the right center bushing. Stock is a carbon high resistance unit. I use the 8412 MSD ones.
Make sure you also have the cap with 8 copper contacts inside.

Yes a ground can do it too.

[68lemans462]

Thanks for the suggestions guys!! As for the normal stuff - yes, I'm using heat sink compound. I'll double check the ground strap in the cap - to be honest I HOPE its missing. Aside from this, I think the problem must be a coil going bad and taking out modules with it, as suntuned mentioned.

No welding done on vehicle, also no battery drain. I'm using the MSD low resistance bushing that came with the module.

[Sun Tuned]

That strap deal up in post 3... no telling how many millions of those deals were/are still running around. The problem i found with them is that some caps and some of the straps are not clearanced as tight as they really ought to be and what happens is that you tighten the coil mounting screws down and the coil frame just sits and squashes the flat metal strap on the cap base. Well if it don't do a good job of that then you'll build up resistance and that equals heat... not good. In a pinch I will always bend that hook tab all up higher than needed to at least ensure it makes contact but there is a better deal.

The ring terminaled wire version I use,easily obtainable at any parts store, has a ring terminal with some fairly aggressive teeth that "dig/bite" into the metal coil frame and you pretty well got a good solid ground with that deal.

Maybe I'm just a worrier???

[Formulas]

I dont think the MSD module has the best record for working long anyways.. Not saying thats the problem just a bit of FYI..

From buying distributors from the boneyard my experience is the carbon buttons will vary widely in resistance,
all you have to do is check it with a OHM meter,
even if its MSD wont hurt to check,
cant remember off the top of my head a good reading from bad but i tested about 7 of them threw out all but the best 2.

If you have a u pick n pull boneyard around snag a used coil grab the best ( visually ) and check it against the old coil with a OHM meter and put it in for a spell see how it goes.

I usually run a ground wire from the distributor body to the throttle bracket as well, cant hurt.

[Chris Petersen]

Sorry I dont have anything to add but, How does it run out with my old heads?

Hope you like them, wishing I would have never sold them, but did need the $ at the time.

[68lemans462]

Chris - the KRE's rock!! I love them! This motor is a BEAST!

Update:
I checked the cap and the ground wire is there. It is not a metal strap on mine, but a wire. I replaced the coil with a unit from carquest for good measure, and threw in the old "GM" module from the bone yard. Engine fired right up and ran good.

I called Summit and they next day'd me another MSD 83647 module.
http://www.summitracing.com/parts/MSD-83647/

I installed the MSD unit and attempted to start the car. Same *****!! Car wont run at all with the "new" module. Pulled out POS MSD module, reinstalled bone-yard HEI stuff, car fired right up. I believe I'm going to give up on this POS MSD JUNK. I have no time for useless junk. I have returned both of the faulty MSD units and asked for a refund. Are any of you successfully using one of these?

[Formulas]

Congrats. Its hard to improve on a good working stock HEI except for the spark curve of course.

I used to scour the boneyards quite a bit to find tresures.. it was suprizing just how much new stuff you could find there for scrap prices.

It was obvious quite a few times people would put new parts on a car to find out their efforts were in vain then junk it

I used to find newly rebuilt carbs, water pumps, starters, distributors, coils, whole engines, or just heads, you name it
But now its near impossible to find a rear wheel drive car here

[rod cole]

I run the MSD module but when I installed mine it changed the timing dramatically. I have not changed it back to see if it follows the module. Mine was way advanced after install. Only know total as mine is race car like. Rod

[Pontirag]

that button deal underneath the coil is important.

I dont run a module since I went with a 6al.

also use one of the module fastening screws to ground the distributor to your block and to the fire wall.