OK, Corvette sitting too long now in the garage waiting on me to act. I'm not 100% sure what is wrong with it but I highly suspect the optispark is ailing. Here are the symptoms:

Car always starts right up. No problem. But when it warms up, it will run as rough as a car can run until it finally cuts off and you roll to the side of the road. After waiting for some time, assuming the car cools down a bit, it runs again but this time, will die sooner as it's already heat soaked to some extent.

I pulled codes and got these codes:
- Module 4
-- H16 H36 H42 H48

- Module 9
-- H62

I cleared out the codes and when they come back, there is some variation but also some similarity. Also got these codes once or twice:

- Module 4
-- H16 H36 H42 H33

- Module 9
-- H62

I have the Helms manuals so I can look up what needs to be looked up. Just wondering if anyone has any first hand experience with a failing optispark? Does it come and go? I hate to bleed to replace this part, only to find out it was unnecessary.

Car has 65K miles and is a 1994 LT1. I've been considering replacing the waterpump with an electric pump (WP118HD) and getting a MSD Opti since it appears Dynaspark is dead. Any advice would be appreciated.

I need to fix this machine as the urge to drive it is becoming overwhelming now.

Billy

 

This does not sound like the classic opti problems that I have had or am familiar with from other complaints. Usually, the opti will not cause engine to just die. If the low resolution pulses are a problem, it generally wont start. The cap if bad will cause poor running but generally won’t kill the engine.

I would first look to some other areas. The ICM is a solid state device which can be heat sensitive. It basically just is an amplifier to drive the coil but they are known to cause these type problems. My next thought might be the coil being defective.

One additional thought would be before I run off into the world of ignition and spark, I would on principal check the fuel pressure to make sure the pump is not failing.

I have heard that Autozone can check the ICM, however on a problem like this, true operating conditions can not be duplicated and substitution maybe the only way to get a competent check. So as the ignition coil. If all else comes up negative, you might end up right back at the opti. But your symptoms warrants other investigation.

The only other far reaching thought might be that you lost the 5 volt pulse from the PCM that drive the ICM. Usually the PCMs don’t cause these problems and I would tend to think not.

 

Your symptoms remind me of when the coil went on my 92.
I'd check the ICM, coil, ?MAP sensor?(not sure if you have one on the 94) And whatever the Helms tells you the errors mean.

 

Yes the 94 has a MAP sensor.

 

Sounds like classic ICM/coil problems. (Ignition Control Module, sits with the coil)

 

I threw most of the same codes about 3 weeks ago. First I did the coil, and then I had the ICM checked, fuel filter, new plugs and wires. I was trying not to spend $515 so I replaced the cap on the optispark. None of these things did the trick.

I put in the MSD optispark yesterday, and the car is fine. Don't waste your time, replace the Opti with the MSD unit, it is worth the $515.

Jack

 

My ride sounds like it is doing the same thing. After New plugs & wires, fuel pump and filter and MAP, its doing the same thing. Looks like I will invest in the MSD!

 

I would strongly sugest you have the ICM thoroughly checked first...

 

I can tell you I have just bought a new optispark about 7months ago, and it is failing now. I was looking though gmtech mag, were I noticed a company called pace performance that eliminates the opticrap system by relplacing it with an ingnition modules and coils like on the ls cars. I have seen it done in an issue of gm tech were it was a huge success, The kits are around 650.00. When my opti dies I am going to give this system a shot. My car is doing the whole surging at high rpms now it wont even rev to 5500rpm. God, I hate the optispark, Its an expensive hard to reach piece of ****

 

Got some real bad news for you JSLT1, you need a perfectly working optispark for the coil pack system to work.

The Optispark distributor is a fantastic system, any distributor with a cap and rotor that will do 100,000 miles and still run no problem with no servicing is good. Its also very accurate spark delivery to boot. Its very commonly bashed on here by alot of people and 9 out of 10 of them wouldnt have a clue what they are talking about or know anything about the system anyway.

 

The technology of accuracy far exceeds most systems for the wide dynamic range of operation. Granted it a bit of a pain to get to, and failure rate is high, but these are on cars 10+ years old and as said 100K on the clock.

Before just throwing an opti at it and assuming is bad, basic checks should at least be made or you just wasted several hundred dollars and a pile of time.

 

The opti is used only for an optical signal while eight individual ls1 coils provide the spark itself or you can use msd coils and msc blaster coils pn (82458) in lieu of the stockers. Thunder Racing provides an ls1 coil relocated kit pn(82458) which comes with mounting brackets and custom cut to fit talyor wires. You may have had great luck with the opti but, not me. Even though I dont have a clue of what I am talking about I think they are pieces of ****. I will be trying one of the new alternatives that are out.

 

How can something that has a high failure rate be considered technology that exceeds?

 

I did not know that Dynaspark was gone!

I bought a unit from them and I really love it, it has been the best investment on my 94 Vette, the peace of mind that comes from having such a high tech piece of equipment.

Anyway I have heard that MSD has a nice replacement to the OEM that really sucks!

 

It is, its exceptional. The cap and rotor are more prone to failure than the optispark, i filled mine with water 2 years ago (it was original and untouched, seals were almost dead), a new cap and rotor went on (under statutory warranty from a dealer over here), still original distributor and its still going strong.

With a cap and rotor 2/3rds full of water, the engine would still start on occation, just wouldnt run real good for obvious reasons. If i hadve thrown a Delteq at it then, it wouldve also fixed the issue straight away. Was my optispark distributor rooted? No.

Im not saying dont bypass the high volt side, cause the multi coil system is better, but you still need a working optispark for the multi coil systems to go

 

quick question here for the ones talking about upgrade to LS1 style over optispark.

I found this and figured it is what you are talking about...

http://www.fuelsystemparts.com/itemd...CC~eq~~Tp~.htm

my question is are there any other companys out there that offer something like this? I mean this setup is $399 plus u have to buy the coils and figure out how to mount them plus your opti must at least be working so it can get proper readings.

 

I'd like to get a Dynaspark but they keep putting me off by telling me that they don't have any inventory. So it looks like the only opti available is the MSD, at least the only one recognized as a high quality product.

Anyone care to comment on this?

Billy

 

Wilson why would you go a Dyna Spark over an MSD mate??

Yeah mate, the Delteq system uses 4 coils instead of 8.

 

First lets differentiate between a part that has low reliability and a part that is operationally superior. A part can have poor reliability and work well, or have great reliability and work poor.

The point is the opti works great because has direct drive so no gear slop. And it sends back crankshaft positioning every degree per revolution or 360 data bits per revolution. This coupled to the ECM/PCM which basically is a computer, which can take this data along with the other engine sensor inputs and make highly accurate computations for timing. Loading, RPM, temperature, throttle position, knock and such are just some input factors that the computer can take to deliver the optimum timing made possible by the optispark high precision of output data.

For more detail: http://www.gmhightechperformance.com...htp_optispark/

Now for the failure rate. Mine failed (stumble on acceleration) with 12 years of service on it. Of course in these years you are going to see failures, but that’s with lots of time and mileage on it. The failure rate was lower when the car was new during the first few years and performance was the same. Or to say another way, the failure rate is higher now because they are 12-13 years old, but the operation is superior to most other distributor systems.

Twelve years of operation and no maintenance performed, not bad. Show me other distributors with no service in that time frame. Putting things into perspective, I would like to see how the MSD system (or others) holds up in the year 2019 (12 years).