I'm working on a 1994 Formula with a pretty stout 396 LT1 in it. We recently had a dynaspark crap out, so we installed an MSD opti.

The new opti works great, no problems with starting or intermittent shut down like the dynaspark. However, there is a new problem. Almost every time you get in the throttle, at some point in the upper RPM's the car will die for a split second. On the dyno, the dyno equipment loses spark signal when this happens. That coupled with the fact that the problem has only surfaced after the installation of the new MSD opti makes me think there is a problem with the new opti.

I called MSD and they are sending me a new encoder for the opti. I was wondering if anyone had any other suggestions or had experienced the encoder failing?

 

Did you check to see if the rotor is getting loose in the MSD Opti? The OEM #6-32 Phillips head screws used on the MSD rotor have a big problem loosening.

If a loose rotor is your problem, see my other posts on how to fix the problem. Basically, longer #6-32 Allen socket-head screws with flat washers and red thread-locker.

If the optical module was bad, you should be getting some DTCs (high or low-resolution pulse missing).

WD

 

REALLY??!?! Why not just have the dyna rebuilt?

 

Is Dynaspark currently in business? And if so, what is their address and phone number?

WD

 

An aquaintance had troubles with the MSD during burnouts, went back to a stocker with a modded stock rotor, he wont tell me what he does too the rotor to mod it though.
Seeing as he has been invited to the PGD the last two years he must be doing something right.

 

The rotor mod is usually just grinding a slope into it so if it makes contact it just skips off instead of catching and tearing the opti or itself apart.

It's a long story with Dynaspark, the unit was replaced/repaired several times under warranty. I don't think the Dynaspark is in business anymore, so that option is out. The turn around on their warranty work was so horrible, that even if they were willing to repair this unit, I doubt we'd of gone that route.

We took the Dynaspark apart after it crapped out and found the problem. Where the harness attaches to the module, inside the opti, the wires were touching. It looks like Dynaspark is taking the end of the stock harness, the long 4 prong plastic piece, and cutting the last 1/2 inch or so off it. They are using that piece to keep the wires from touching one another where they attach to the module.

Our 1/2 inch long piece of stock connector was missing the dividers inside it, so the wires would make intermittent contact with one another. You could see where the dividers were at one time, but for some reason they had rotted or melted off.

Thanks for the tips on the screws Engineer, I'll check that out when I am replacing the encoder.

 

I just came from Speed Inc over by Chicago and I have the exact same problem, at 5300 rpm hp drops off by 60 hp and picks it back up and drops off again @ 6300, motor is setup to pull well into lower 7000 range but MSD box is set @ 7000

 

See my reply in your other post.

 

If you think the MSD Opti is the problem (high RPM miss), step one is to remove the distributor cap and see if the rotor screws have worked loose.

WD

 

We took the cap off before we put the MSD in, but it was more to just look inside out of curiosity than anything. Unless one of the screws was visibly loose, we wouldn't of caught the problem.

I am fairly certain it's the MSD opti because the problem wasn't there until we installed the MSD unit.

The free replacement encoder from MSD should be here in a few days. When I pull the opti to replace the encoder I'll check the screws then.

Once it's all back together, I'll report my findings here.

Thanks for all the help!

 

Ever since i put mine in it spits at wide open throtle

 

I don't think the module is your problem (high RPM miss), but we'll know when you get it apart. Again, probably a loose rotor.

WD

 

It appears that the higher horse cars have the problem most of the time. I thought i read a post that if you use some thread lock it actually causes some problems making the screws work loose sooner. Something happened and it held worse than if you actually left it alone as i did.

 

Red thread-locker "will not" attack the plastic resin in the MSD rotor as someone alleged and posted in another thread! I can say that with complete certainty. I’ve removed and inspected the rotors for that problem and the rotors were perfect.

Blue thread-locker can attack some plastics; however, I don’t know that it has been proven to be a problem with the MSD rotors.

True, a high HP engine with a large cam will have more valve-train vibrations and harmonics. However, the potential for the rotor screws to get loose is there in all engines (low and high HP).

Again, I recommend the slightly longer Allen socket-head screws with flat washers and red thread-locker. That combination is working for me!

WD

 

Well, the car went back together today.

I took it apart this last weekend, one rotor screw had falled out entirely, the other was loose. I tightend the screws and installed the new encoder. The car runs great now, no high RPM miss or dropping out.

Obviously, the problem was more than likely the rotor screws. I can't say that was the problem with 100% certainty because I did install the new encoder at the same time, but I'm pretty confident that the rotor screws were the problem.