i've had this on-going problem now for a long time. i have a 97 z28 with the LT1. hooker headers going to 3" flowmaster exhaust. no catalytic converter. k&N cold air intake, bbk throttle body, comp cams roller rockers and lifters and it has a mild cam in it too. i have the fancy schmancy msd pro billit distributor, and an msd 6AL ignition module. my problems started when i got the car, and i think they are the reason the guy sold it to begin with. i don't know how to get ahold of the original owner. i bought it off of a small lot. i had it and it ran great for a while then it started misfiring and acting goofy. i found out that my distributor had somehow got all corroded and when we took it apart it had carbon deposits from arcing all over it. i replaced it and the water pump just to make sure that it wouldn't get wet. about 4 weeks later it was acting up again. we warranty replaced the distributor, but then that one accidentally got a little wet. so we replaced it again. then we found out that the pin on the end of the cam shaft that drives the rotor was too long and it was mashing everything up. so i ground it down as low as i needed to, and it still somehow got all fubered up and went out again! i got tired of taking my water pump off to replace the darn thing, so i went out and got the msd pro billet one that just came out. i did not install it myself, but i had someone who does know what he was doing do it. he said i did not need my msd box hooked up so he left the stock ignition set-up on it. i drove it like that for a while and it progressively ran worse. it would run okay for about 5 minutes, then it would bog down under a load. i was losing at least 2 cylinders when i mashed the throttle. so i hooked the msd up a little bit ago and it ran grrrrrreat!!!! well the other day i went to start it and go get gas. (bp ran out of regular unleaded so they were selling premium for 3.86. great deal huh...) well i crank and crank and crank and no start. i try again and it starts then dies. i hold the throttle down and do it. it revved up to about 3 grand then died. it is exacly what happened every other time my distributor went out. obviously my msd box is the problem, but why. the only thing i could think of is that it is hooked up directly to the battery and not to an ignition wire. that may or may not be the problem. i was just wondering what i could do. im going to unhook the msd and see if it runs. if it does, great, if not i don't know what to do. what do you guys know about the coil pack swaps, and which ones are the best, and i believe the whole bogging issue is due to a timing problem. is there any way to chang timing on optispark past the msd distributors 7 degrees?

anything known or advice would help. thanks.

 

Timing adjustments should be made in the computer, NOT with the opti. The MSD while in theory a wonderful upgrade has failed miserably in the real world.

If it keeps eating optis though I would replace the vent harness. If the feed side plugs and you get vacuum building in the opti that can cause missfire as will the ozone buildup from lack of fresh air flow.
Cost a whopping $10 but most guys just keep replacing whole optis cursing it as a bad deign. Funny thing is there are a lot of experianced successfull guys running stock optis.

 

Stock is the way to go. My MSD quit and left me stranded. Replaced it with a stock one and runs like new.

Get a new stock vented one and you should be fine.

 

i wonder how many msd failures are due to the rotor backing out, prolly 98% of them. i cant see it being the new optical sensor.

 

I might have missed this,but did you heat up the O2 sensors?Sounds dumb,but they do talk to the computer.They like hot.My02.

 

The optical sensors do fail. Rotors do back off, parts do rub.

A 97 comes with heated O2s and if that circuit fails it sets a CEL.

 

Lets clear out the superfluous info, and trace the chronology of events:
How many miles on the car? Was it the original Opti?
What brand Opti did you use for the first replacement? Did you ever check this distributor to see what failed? By "acting up" do you mean the engine went back to "misfiring and acting goofy"? Define "acting goofy"... that's really not a descriptive technical term that would help people analyze the problem.
What brand Opti did you get for the second replacement? Did the Opti actually run OK until it got wet? How did it run after it got wet? Did you have the same problems with misfiring, or did you just replace it because it "got a little wet"?
How long was the dowel pin? How short did you grind it down to?
When did you buy the MSD? Its been out for a couple years. The early ones had a lot of problems. The newer ones aren't much better. How does replacing the factory Opti with an MSD eliminate removing the water pump for replacement of the Opti?
Do you think that this may be pointing to weakness elsewhere in the ignition system? Have you had the coil and IC module replaced? Have you ever scanned it for codes at any point during the course of these multiple Opti replacements? Has a data log ever been run?
Againk, did you scan it for codes? How did you come to the conclusion that "obviously (the) MSD box is the problem"?
Do you always run premium fuel, or did you only buy it because it was cheap? Do you normally run regular?
Its normal to hook the MSD-6 boxes directly to the positive side of the battery, not to a switched source.
You need an Opti with a healthy optical sensor to support the LTCC 8-coli setup. You also need it for the Delteq 4-coil setup, but the developer of the Delteq has disappeared and it would be foolish to consider buying one. It would probably be a good idea to figure out EXACTLY what is causing your problems before you consider going off on a new system. If you don't correct the original problem, you will just be wasting time and money. We all condemn the "dealer" for trying to solve problems by replacing parts.....
How did you reach the conclusion its "bogging" (first time you mentioned that word) due to timing issues? Ifr its run fine for periods between Opti changes, its not a timing issue. Attempting to play with the timing without knowing the cause of the problem makes no sense at all. And as noted by others, you don't adjust timing with the Opti, you do it in the PCM.

You need to stop replacing parts, and concentrate on what's actually causing the problem. Dwayne mentioned the Opti vent system. Is your vent system correctly hooked up and working?

 

And I'm completely confused as to what this has to do with the problem. Please explain.

 

i bought the car with i believe 112,000 miles on it, and i am not sure if it was the original opti. shortly after i bought the car i had a cooling problem so i replaced the thermostat with a 160 degree one. i might have accidentally got the first one wet that way but who knows. all of the opti's i bought were AC delco except for the msd one. i was hoping that if i put the msd opti it would fix the problem and i wouldn't have to change it anymore. when i say acting goofy, i mean it wouldn't start easily. it would backfire a lot, and the tach would work intermitently. the only time i had ever hooked a scanner up to it the codes i got were for the o2 sensors, and for a random cylinder missfire. i bought the msd opti soon after it came out, and i had no problems starting the car with it or anything like that until i plugged in the msd 6al. every time it got wet, it started missfiring. i did hook up the vent tubes correctly, but i will check to make sure they are still hooked up. i always run premium.

 

sorry to bring back an old post. i forgot to update this but i called and talked to msd and they went through the codes i had. none of which were for the opti. i wound up replacing the ignition module. (not the msd box to clear up any confusion.) msd said that it was failing when it was getting warm which explains why it did not want to start on hot days and once it started it did not want to run. $100 bucks later she started right up. still has a miss after it goes into closed loop. losing cyl. 7. gotta look into that. this is just for the guys having opti problems and looking for any ideas as to what the problem could be