[QUOTE=chatham;1589699757]
File In Section: 6E Engine Fuel & Emission
Bulletin No.: 87-65-27
Date: December, 1998
Subject:
Engine Miss/Poor Driveability Symptoms
(Install Opti-Spark (ABITS) Distributor Assembly Service Kit)

Models:
1994-96 Buick Roadmaster
1994-96 Cadillac Fleetwood
1992-96 Chevrolet Corvette
1993-97 Chevrolet Camaro
1994-96 Chevrolet Caprice
1993-97 Pontiac Firebird/Trans Am
with 4.3L or 5.7L Engine (VINs W, P, 5 - RPOs L99, LT1, LT4)

Condition
Some vehicles with the above engines and equipped with the Opti-Spark (ABITS) ignition system may exhibit an engine miss and/or poor driveability symptoms.
Cause
The (ABITS) cap and rotor may exhibit carbon tracking, cracking, or water intrusion which can cause an engine miss and/or poor driveability symptoms.
Correction
Perform strategy-based diagnosis. If it is determined that the ABITS cap and/or rotor is the source of the concern, then a service kit may be now implemented instead of a complete ABITS assembly.
Parts Information
There are two (2) variations of Opti-Spark Distributors. It will be mandatory to identify which type is to be serviced for proper parts procurement.


1.Opti-Spark Distributor II (Pin Drive - WITH positive vent system) can be identified by the intake manifold vacuum hose connection (3), air intake duct hose connection (4), or non-splined pin drive (1). Refer to Figure 1.


2.Opti-Spark Distributor I (Splined Drive - WITHOUT positive vent system) can be identified by the splined pin drive (1), or the lack of intake manifold vacuum hose connection and air intake duct hose connection. Refer to Figure 2.


Important :it is necessary to use tool J 39997 (or equivalent) for the Distributor Cap Screws and tool J 39998 (or equivalent) for the Rotor Screws. Parts are currently available from GMSPO.

Warranty Information
For vehicles repaired under warranty, use:
Labor Operation Labor Time J452O (B/D/F Cars) Use published labor J436O (Y Car) operation time


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This is a well known problem and chevy has its TSB for a long time ...I just loo up my all data and its all there......As I remember a few months ago I fixed the last 97' LT1 trans am with the breather vent replacing the non vent original and my local chevy dealer lonestar chevy has the revised vent distributor prts #10457702 all day long ....

 

Petris sells a Gen 1 that comes with a kit to make it vented. Very easy to do and so far with mine it works GREAT! It is not cheap $550, but it comes with a 5 year warranty.

 

why $550 is not cheap ???? ...this is what retail on a legit dealership...no difference than an hp pc form sears ???

 

kcbc, im sure your are just trying to helpful, and maybe its just me, but I find you comments bizarre. also the diagrams above with the alldata info you posted are not even close to the subject matter and they keep changing. every time I look its something different. once it was a steering column and then a northstar engine..... strange

 

This is not helpful, but lol
Maybe it's a connection or wiring issue between the opti and the icm/coil. Make sure all wires are good and that the connectors and clean. Also checking for clean grounds isn't a bad idea when wired things happen to electrical parts.

 

I've been to the "OPTI CIRCUS" too. What a nightmare!
I always autopsy anything that comes off my cars to see what failed and what I can do to prevent that from ever happening again.
The first failed because of a leaky waterpump so I threw money at it with a really beautiful MSD. Built like a tank with very high quality workmanship BUT filled with crap electronics! It took me quite a while to track that problem down because it gave no codes. Stumbled at anything over 4000 rpm and gave an occasional missfire and finally smoked! The next one is an AIP I got through Ebay. It's a cheapie but has a good quality optical sensor. I voided the warranty by taking it apart and modifying it. I tossed their tinplate metal shield and installed my own shielding and grounding. I modified the rotor as well by decreasing the rotor to terminal gap and JB welding the rotor blade to a beefed up base from another old Opti. (That sucker isn't going to come apart) I increased the size of the top vent for more flow and put a vent tube and extra heat sink on the sensor to keep it cool. The IN tube always has to be larger than the lower vacuum outlet to keep from pulling a vacuum inside the cap. You just want air to flow through. If it pulls a vacuum inside it can collapse the cap or make the rotor scrape.
So far my modified cheap Opti has gone close to 10k with no problems. [Now that I've bragged on it, the damn thing probably won't start next time]
Good luck with your install and hope you can get a vent put in with no problems.

 

I have purchased a NOS AC Delco unit that I found hoping OEM will give me the life I need. I have not removed the sac city unit yet as I am waiting until the other arrives and do it at that time. when I do remove it I will open it up and see what it is like.

what appears to be obvious about this issue, through my research and my review of postings on this site recently and over the years, is that no one has the answer. some people are running the original still installed opti and are fine with a 100,000mi. others are on the 4th or 5th ones trying both vented and non-vented some have used non-vented and others swear vented is the only way. venting does not seem to improve the quality or the life of the unit as indicated by the failure rate of each type I am a prime example of that. the original non-vented failed at 80,000mi (not bad)and was replaced with a vented dynaspark that failed at 11,000mi. after opening it up I can say that it failed for possibly two reasons, corrosion and/or perhaps a bad bearing. these two issue are not electrical issues that helped to cause or caused the failure but the collateral effects are electrical issues. it will be interesting to see why the sac city one failed after I open it up. whether you purchase a $700 unit or a $150 unit doesn't quarantee long life.

the suggestions that you should only purchase vented or vent what you purchase may be good advice but it doesn't seem to be supported by the masses who have done it and still have failed opti's. so venting doesn't seem to be the answer. what appears to be the running theme is quality of the opti and most people lean on the optical sensor. after opening up the dynaspark unit I was actually amazed at how simple of a device it is. why such a problem? seems to me with as many of these that are out there some one could solve this problem with a much better designed and built unit. buying a 5 year warranty is great but replacing the unit isn't the problem, getting to it to replace it is the PIA.

so should I vent my NOS opti that is coming? should I run it as is and hope to get 100,000 miles out of it like others have? what is the answer? no one has the answer that I have found. it looks to me like I have a 50 / 50 chance either way of the unit lasting or not.

 

Thanx for pointing out the ambiguous,misleading direction from a TSB
issued by GM --> NOT ME....if u making a living on automotive repair then u should know better than any1 here ...all TSB and recall repair are most a generic of most model they have problems ...all GM models are not setup the same .... professional automotive shop improvise whatever the car they work on and see it fit ..... they don't teach us how to fix the car we work on ..its up to u applying the change info from them ...u have any idea how many midnite oil we pull to figure out crab from these engineer and manufacture bogus as a shop ? ....

 

1st ...critize the diagram to GM not me...this is the ORIGINAL EQUIPMENT general motor issue TSB to their dealership and the industries...try to appreciate your mechanic work to fix ur car in days not months like people here on the forum...more bizzare in what a shop have to deal with when these ambiguous fix that professional have to deal with and most customer expect us to finish it in 2 days ...
welcome to our world

 

whats the difference is that different then u are trying to fix a warranty TV from sears that after warranty repair it only last a year???.......


As I point out early ...they made the product not u .not me...so if there are no replacement part that last longer than 100 K mile after O.E. manufactured ....its no difference than u wanna fix and demand an old tube TV or junks make oversea that are build for dispose....


MY snap on 350 swivel rachet never have problems since I bought it 15 years ago ...but today same model same design only last 6 months ...my mechanic jump on the snap on truck every few months to have those rachet replaceing ......part of progress

 

Clearly I live in a different economic stratosphere than you do, for me $550 is not cheap money.

 

I bought an ebay one and the car wouldn't pull to redline.

I bought an autozone one and it came with a cap vent tube that looked like an extra spark plug wire terminal. I routed a tube from it to manifold vacuum plus made another vacuum vent from the holes on the bottom of the distributor. Car pulls to redline and runs great no problems so far.

My 2 cents with the whole optispark distributor thing is that the more expensive they are doesn't equal how long they will last you.

 

out of curiosity which brand did you purchase, the duralast?

 

Not at all ..its a common double standard ....what u do for a living ??? .... price of product and service in the country is free market ...whatever the price out there it is market driven .... another word if the ebay stuff and brother in law ,autozone ,internet work without the warranty and backing up as retail... then dealership parts will be price out of the market ...so it's the other way around too....when a parts is offer over the internet with no overhead and no origin of R&D... if it goes wrong and set fire on ur car ..that's the differences.... how bout most of the electronics and other copycat counterfeit that is made oversea causing u or most middleclass professional their job ???


I'll make it real clear .... it take much more skills with ur own tools to be a mechanic than a medical equipment service technician ....guess who get pay more ....guess who only work 40 hour week with union protection and job security ...... We replaced 3
brake switch an VW TDI jetta from worldpac and IMC which are the biggest wholesale auto parts to independent auto repair shops....none of them work till we went with an OE from the dealer .. whos paying us to do the research and cover what customer complaining that we dont know what we are doin??? ...
Look up 1999 Ford F150 pickup truck 4.2 liter V6 ....ford change the harmonic balancer 3 times in design and get it right .....we are covered every time because of the wholesale ,retail and repair chains
of relationship ....what about others who have no overhead and no warranty selling those parts over the internet and most of the order don't even pay salestax..... I pay the market price for plumbing,a/c ,medical so as most of us ....so when all the chevy dealer sell for whatever the price its set ...whats the problem?


what u are suggesting is to undermine the market price and circumvent retail and service while expect the same result as the repair from the chains of industrial standard ..whats the difference between BP using substandard lower price parts and causing oil spill ?? ...yes they have to be liable for it and the internet or autozone only good for giving u another 1 .... the part from the dealership is structure to be the same or equivalent as the 1 on the car coming out from the show room when it was brand new ....there are no law in safety standard nor testing as if some1 copy it in china and sell it over the internet or mail order ...that's the difference and that's the consequences for a better deal ....

 

Honestly I don't remember, but being Autozone I would say more than likely it was Duralast.

I like it. Looks more rubust than the ebay one I had previously installed, plus it came with that cap vent. Around $150? And I know most of the people at my Autozone so I wouldn't hesitate taking it back if I had a problem with it.

I've been beating the crap out of the car all week long, redlining it, banging gears and it hasn't missed a beat. Matter a fact i can't remember the last time it ran so good. For the price and if I couldn't return it I wouldn't hesitate buying another.

 

Vented Opti's must also be careful when running K&N filters. The K&N oil will vent through the air tubes and will eventually fog up the photo sensor lenses. Best to put a separate little paper filter like a dirt bike filter or little fuel filter on your Opti vent tube. A friend ran his vent tube all the way into the cabin. I'm not so sure that is such a great idea either because my car has felt like a swamp in August after sitting outside for a couple of hrs. on some club cruises.

 

Mine goes to manifold vacuum. (matter fact right now its just sitting under the fuel rail cover until I buy the vacuum T) The Vent I have set up to the optical sensor area is on manifold vaccum right now though.

 

Its r&d stuff ..not something right away...look at the recall on takata airbag ....they recall model since 2002 but till last few years problems does not occur till much more miles later ....
that's what the topic on this thread ..why it crap out in 3 yrs or 18 months?? .....I'm TELLING U I BOUGHT MY 09' z06 a few months ago.... I check all monitors ready before I BOUGHT IT ...ONLY 4K MILES .... its got a p0420 when it came off the trailer and never goes away ...I do my test and proof its not the cat but the software .....I flashed it and fixed it ....my point is we have no control on the parts quality belong a standard warranty ...how r u suppose to know the price and spec chevy order from a vendor ..even worse how u know some aftermarket trying to make some without the spec and quality control of Chevrolet ?


the moral of the story is today auto parts quality are no difference than ur flat screen tv .....if don't believe me...ask any1 who owns a landrover.....the value of landrover only worth when it is under factory warranty.....check this out and stop beating on car manufacture ...look at everything in the past 20 years ....the price of a car does not match the price of gas,milk ,cigarette or most of our daily expenses ...so unless consumer are willing to spend 3 times on an entry level vehicle and it will last 20 years .....then some corners are going to be cut ..its that simple ....and I aint complaining ...cuz there are no way I can pay $46 K for my 09' Z06 as a super car performance if the price of cars are same rate increase as others...
my 96 landcruiser had 300K and still on the same starter and alternator and also I went thru water over the head lite 3 times down here during hurricane still working ...but I can tell u I replace all the Yukon ,Tahoe,ck pu' alternator that is 07' and up with around 100K miles ..... the car manufacture have to pay same people same todays living standard to build the car ...also the vendors contracting the parts ....u know it ... gotta cut corner on the parts so u wont buy a car last forever ..or else they are gonna be outta business

 

Chatham- Hope the NOS unit solves your problems and lasts for a long time.

kcbc- What's your opinion on Ball Park franks vs. Nathans?

 

There's an IN and an OUT. The OUT is at the bottom of the Opti to pull moisture out the bottom and should go to your vacuum source on the manifold. The IN is at the top of the Opti and should go to a clean fresh air source. The plan is to have air flow through it but not a vacuum applied inside. A vacuum inside would be bad because it will suck the cap down till it breaks and squash the cap into the rotor and most likely breaking it as well. The stock hookup for air to go inside the top of the opti is on the driver side of the air intake pipe right behind the mass air sensor where it gets filtered air. The IN hose and ports are larger than the hoses and ports on the vacuum side so you can never have more air sucked out than you can get back in to replace it through the top port.
When the engine is running, NEVER put your finger over the fresh air (IN) side vent hose to see if it is pulling air in. It will suck the cap down just like a power brake booster or cruise control diaphragm and you'll get to replace the opti again. ( Had a friend hook up a vacuum gauge to the fresh air side after a brand-new install and the engine went CRUNCH, POP-Backfire and stopped running. Collapsed and broke the cap on a brand new Opti! REDO )