Yup, happened to me, too (may have been the problem all along). The Optispark on my 94 FIrebird Formula is about dead (148,000 miles original part). I was looking at fixing it and realized now would be a good time to upgrade to an MSD opti and ICM. While searching I noticed that MSD has two very similar products with huge difference in price. Being not so familiar with this car (first project car really), I need some schooling and/or advice.

Exhibit A (searched for distributor): MSD part# 8481 (distributor cap and rotor). About $160 (almost half the cost of an AC Delco)

Exhibit B (searched for optispark): MSD part # 8381 (Pro-Billet distributor). About $510

What is the difference? Which should I buy? I have saved enough for the more expensive one, but as always would like to get the best bang for my buck. It does seem odd to me that MSD would produce a part that is cheaper by that much than OEM.


A little history. Car was stalling. Replaced fuel pump, ICM, and fuel pressure regulator). Worked (for a while). Started stalling again, but only on long road trips (Southern Utah to Tucson). Restart after a few minutes and unplugging then replugging battery, no more trouble for several months. Stalled again (another trip to Tucson). Made it much further, but this time no restart. Replaced fuel pump again, this time OEM part. Still wouldn't restart, so upon further troubleshooting found out it was teh anti-theft system, used my spare key and problem ceased. For about 6 months ran great (a little rough idle and odd smell but nothing serious). Another trip, this time after picking up the wife and grandbaby in Vegas, car was running good, stalled south of Kingman, restarted alright, but would stall every 2-6 miles. After taking a break for several hours, made it to Phoenix and problem started up again. Found a guy with an old Snap-on OBD1 code reader (no check engine light, but figured I had to reset the AC codes anyways, so let's take a look). Code 16. AHA! Renewed hope for the project.

 

O.k, if it's the original opti, this is what I'd do.

Pull the opti and take it apart (if the optical sensor has a Mitsubishi logo on it, it's original and likely still good). You'll probably find it is dirty.

If dirty, clean it making sure to get the lenses on the sensor as clean as possible. Think of it as a CD player (basically how it works). Reassemble with loctite on the rotor screws. And install a new cap and rotor (the $160 MSD is the cap and rotor ONLY). Replace the timing cover seals and reinstall the optispark.

If it's not dirty, get an AC Delco, Delphi, or MSD optispark (the $500 MSD is the entire Optispark, so sensor with base plus cap and rotor).

 

As he ^^^^^^^^^^^ said....the price difference is bc 1 your just getting pretty much a couple new parts for your opti an the 2nd is a whole new opti. Hints whys its 500 bucks. Now my opinion with these optis, the msd optis are over rated. Theres ridiculous in price bc of their name I think. Ive always used either an dephi's or ac delcos. But then again ive used the 260 dollar optis from autozone (forget the brand but it was the cheapest one they had) an the car ran perfect for over 40k miles..(sold the car) but im sure its still running fine with the autozone opti. I never recommend replacing just the cap an button..1 its not exactly a walk in the park to change these things, an 2 once your in there why not just replace the whole damn thing so you KNOW its all new?! Also, if you do choose to take your old opti apart, regardless weather its fatory or not, an weather theres any signs of moisture, cleaning it may not always fix it. Ive tried just about everything with these damn things an the only way ive made it with trouble free optis is just simply spending a few more bucks an replacing the whole thing! Now one thing is forsure an I bet everyone on this forum would agree, do NOT buy the cheapy 50-70 dollar optis off amazon or ebay. Ya get what ya pay for

 

If there's a Mitsubishi sensor in the opti, they are Damn near bullet proof. Too often the new opti (the cheapo ones) fail within 90 days. I just replaced a friend's 90 day old Oreilly Opti and ICM. At that price point, you're better off keeping the Mitsubishi sensor and replacing the cap and rotor.

Agreed the MSD is over priced, but it's the third best option that has proven far more reliable than anything other than an AC Delco or Delphi unit. And the MSD is the only one you can get brand new, not remanufactured. MSD also rebuilds them for about the cost of a cheapo optispark.

AC Delco and Delphi brand new are the best choice, but good luck finding one.

 

The main advantage I've noticed with an MSD over a Delco is if it ever goes bad, you can send it back to MSD and have them rebuild it for a fraction of the price of buying a whole new opti. Last I checked, it was only about $120-150 to rebuild it which is way better than $400+ for a complete new one. Having said that, I've got an MSD running trouble free for about 4 years now

 

I have a billet MSD for sale (new) if interested, PM me.

 

Well damn, I paid $258 for a Delphi back in 2014. Seems they dried up and AC Delcos are $375.

 

Had both spline and cam driven msd optis, def loctite the screws, other than that they worked flawlessly