Nathan Plemons

Once again another thread has got me thinking about this. People are so quick to assume that any ignition related problem on the LT1 is immediately the optispark. Personally I always think the opti is the LAST possibility simply because it is the most expensive. I always check out the spark plugs, wires, and coil before even considering the opti.

I know a LOT of people who drive LT1 F-bodies and it is very rare that the optispark really is the problem. I've actually seen 3 people swear up and down the opti was the problem just to find out that it wasn't after a whole lot of work and money to replace it. I've also personally delt with a several cars in which plugs and wires solved the problem, these have the original opti. One has 95k miles, another has 130k.

So I had to think about that for a little bit. Why is the opti so often not the problem for the people I know, yet gets blamed for everything on Corvette Forum? The only answer I can come up with is how much is the car driven. Everybody I personally know with an LT1 uses it as a daily driver. A good deal of people on the forum who complain about the opti obviously are not daily drivers. If I see somebody with a 92 who says they had to replace the opti at 11k miles and again at 20k miles yet only has 30k on the car I just have to roll my eyes and say "well, yeah!"

Cars are meant to be driven, period. This may be especially true of those cars with the vented opti. Think about it, the vented opti is there to allow engine vacuum to pull air through the opti and eliminate moisture. Ok, so what happens if you don't drive the car? Hmm, you draw in fresh, damp air into the opti and then shut the car off and let it sit for a week, a month or more. That moist air will just rust the internal components of the opti and you'll have problems when you start it up. Meanwhile if you drive the car the constant airflow will tend to prevent that rust.

Just some thoughts, please answer my poll so I can test my thoery.

Aggravated4life

Good theory going...but what about the idea or possibility that more Vette owners clean their engines more often and have gotten water in the opti?Seems to have been a "newbie" mistake by lots of new LT1 owners hosing the engine down.Just sort of an afterthought to your post.
I think your on the right track though.
:)

Nathan Plemons

Bill,

That's a good possibility as well but in that case in my mind anyway I can't really fault the opti. Spraying water under the hood of a car, any car has never seemed like a good idea to me. Opti or not it still has an air intake somewhere, countless electrical connectors, etc. If you don't toast the opti odds are you're going to toast something else eventually. The thing is that 2000 miles later when your alternator goes out and perhaps you don't know why you'll never give a thought to that water hose.

I wouldn't even spray water under the hood of my dad's 46 pickup, but hey maybe that's just me.

:cheers:

vette92_1

Excellent theory. Another forum member and I was talking about this exact same theory just last week. I was telling him about my 92, I have told this story on here before. When I first purchased the car, I had no idea that you shouldn't get the opti wet. Needless to say I washed the engine and the car ran like crap, but since I figured it would dry out I just kept driving it with it spittin and sputterin for days. After about 1 -2 weeks it cleared almost completely up except at very high RPM's which eventually cleared up after 1 -2 months.

Here's the cool part...that was 5 years ago, and I have even had 1 radiator hose bust and got the entire front of the engine wet and I had a water pump that started leaking on top of the opti and I still have not replaced the opti yet. It curently has 120,000+ miles on it.

To go along with your theory, for the most part I drive it every day, except when I'm out of town on business, which usually is no more than 2 or 3 days at a time.

JCAIRE2

Hmmm, Chris, Nathan, I think this means we have a consensus going for this theory. Sounds good to me at least. Water on the opti makes the degree wheel rust, and the opti can't see through the slots very well. Maybe if GM made the degree wheel out of a better grade of steel, noone would have this problem. Anyway, I think it's a sound theory and makes sense to me :cheers:

SPD DMN

My wife's 93 has the original optispark. 95K miles on her (the car) and it is a semi-daily driver.

My '94 on the other hand, gets maybe 4-5K miles a year if I am lucky and I have replaced the opti 3 times. The seals are always good on mine that I pull off, but there is always something wrong with it internally. The first replacement was putting a new one in when I put the motor in. Second one was diagnosing a problem that I can not entirely attribute to the opti. Third one was just a few weeks ago and it had green oxide corrossion all inside of the cap and rotor with some rust/sand looking crap all over the sensor wheel. The one I have on there now should be good for a while though ;).

STL94LT1

My car is not a daily driver, and the opti went out at 12,000 miles.

silver & red CE

Lost mine on my daily driver 96 Impala SS after ~30K miles. It set the dreaded random misfire and high res signal lost PCM codes.

Theory's not bad, but there's lots of garage queen L98s that never have ANY distributor problems. Mark McPhail (GM engine guru) spoke at an Impala meeting and admitted it was weak because "perhaps we reached a little too far". IMHO, it's weak compared to other solutions.

Here's the silliest thing about optispark, GM wanted 1 deg angular accuracy for misfire detect (to meet OBDII), so they used the crank driven cam chain to drive the opti's resolution wheel. The joke is that the cam chain has all sorts of production slop, there's no way to have 1 deg accuracy with the opti as long as the cam chain is in the loop. So the reason why they mounted it under the H2O pump never gave GM what it was looking for. Even funnier is that Ford and Chrysler did it (misfire detect for OBDII) with ~$5 worth of electronics (ha,ha).

Last point, I wonder if the OEM platumin tipped plugs are a big cause of opti failure. When the puck pops off, the effective plug gap goes to over 0.1", the ionization voltage to breakover the air/gas mixture and spark is much larger than GM expected, this could be the cause of the carbon tracking seen inside of failed optis. All my plugs had lost their pucks on my Impala....

Eric


[Modified by silver & red CE, 12:47 PM 5/4/2003]

Squareseven

I have 61k miles on my 95, and as far as i know the opti is still original. :cheers:

Strick

You have a valid point. At first, I thought you had a flaw in you thinking, but after thinking about it, you might be on to something. You are right, I'm the first to look immediately at the opti for the symtoms given. Why? Because I took mine out and looked inside and saw an incredible mess. And my water pump had a small leak at the weep hole of the pump. To me it seems that the opti will leak not only around the seal/gasket, but at the connector that goes to the ECM. Having a 92, I vented my new opti and it doesn't appear to me that cold damp air could get to the opti as the engine compartment is warm which would dry anything out. So, what's the answer to our opti problem? Who knows, all we can do is keep trying to come up with answers. The C-4 is too nice to let this keep it down.

This is why I like the forum; good thoughts and good answers. :grouphug:

:flag :flag :flag

Nathan Plemons

Strick, you bring up an excellent point as well. I may well be flawed in my reasoning! I didn't post this as a "know it all" solution, I'm just trying to see if my theory makes sense to anybody else.

There have been some excellent points brought up already and the thread is just a few hours old. Lets keep them coming :cheers:

jz94

When I got my car, the first thing I did was spray the engine with S100, scrub, and hose down the whole engine compartment! That was before I discovered Corvette Forum. But at least I used compressed air to dry everything immediately. My car has 76k miles and I assume the orig. optispark and waterpump. I haven't had the (optispark?) symptoms people have described. (Insert knock-wood avatar here). I agree with the daily use theory for ANYthing mechanical. Perhaps living in AZ has helped, too. (It's a dry heat.) :yesnod:
Thanks to all the people sharing their experiences here. I'm learning alot.

Strick

Let me hear an "A-MEN" One more time "A-MEN"

:flag :flag :flag

96GS#007

I like the plug theory Eric had...seems to fit my situation. 1st Opti died at 36k miles and was replaced under warranty. At that time, they also found that couple of the plugs were missing their pucks. 2nd Opti just went at 68k miles. 6 of 8 plugs were missing their pucks.

Although my engine is clean, it's never seen water from a hose. It's also not babied :D

96GS#007

...and one other thing...It's always surprised me that they bothered with the Opti. After all, the LT5, the 3.1L V6, and engines from other manufacturers at that time were already using DIS. Random thoughts.

Mr Mojo

Nathan, I agree that usually other things should be checked as well before assuming the worst.

In my case, one of the wires was rubbing on the water pump.

In another case, I had two plug wires touching the exhaust manifolds, which I replaced the set with new plugs also only to find that the problem is still there.

Get this, this is on my '93 which is not a daily driver and the non vented opti. The car runs fine on a sunny day, but any hint of rain or rain the night before, the car is a sputtering idiot.

Car doesn't even have 40,000 miles on it and the opti has crapped out.

I have the greatest solution for it and I will post about it after I get it going.

bogus

I only replace, or recommend replacing, the opti as a last resort - or - when the code 16 is shown. Mainly, because of cost and the pain factor for installation.

And even then, only after a couple of occurances of the dreaded code 16.

I agree that the opti is problematic, or, at the very least, perceived to be problematic.

There have been a number of problems listed, sometimes, depending on mileage, I will recommend the opti, or, at the very least, ask mileage for reference to maintenance intervals.

Personally, I think the number one problem with the ignition is related to those garbage AC Delco platnum plugs that people insist on using - just cause GM says to. Those POS will loose their platnum buttons by 50k miles... the car will run like crap. When you install those plugs, they measure at .050 - as they should... after the button's fall, the gap grows to .065!!!!!

BTW, I recommend NGK. The iridiums seem to rock.

biggrizzly

Mine has 103k on it, is a daily driver and runs great. No idea what early history was. Although this car sat somewhere for some time before I bought it.

LT4Sam

I just replaced mine last week with the Dynaspark. I eliminated all other possibilities before I did so and the car now runs as it should. I believe that in my case the aftermarket coil caused the premature failure.

Sam

Half Fast

I agree that bad plugs and wires can cause optis to prematurely fail. Electricity will always seek the path of least resistance. Increasing the voltage with an aftermarket coil or ignition box will stress it also. I would love to be able to get heavy duty dielectric caps with bronze posts for the opti. I had heard that someone was working on it with an aftermarket supplier.