I have a 1996 LT4 6 speed. I am at whits end regarding the opti spark! At 55,673 miles I installed a new water pump and opti spark. At 57,588 miles I installed another unit as mine whent bad???? At 58,401 the opti spark again whent bad??? Now at 58,855 It is bad again???

Counting the origional this will be the 5th unit in 3,000 miles (yes 3,000 miles)

The dealer is saying it is because I do not drive the car a lot and store it over the winter. It is stored in a insulated building on my property with another vintage car. Clean and dry. last year out of desperation I purchased one of these car storage bags. Took the car out this spring and the opti spark lasted 454 miles???

I can't believe I got all these bad units, the dealer will only warrent for 90 days and they claim there is nothing else wrong. Becoming a very expensive car.

Can anybody give me an idea of what may be cusing this?

I drive the car and it runs great, pull in the garage and when I go back to use it again, nothing but crank. It has happened this way each time where I have to have the car towed to the shop. This makes no sense to me!

Any help would be appreciated

tmach

 

Could the dealer be hooking up the vaccuum harness wrong? I heard if this happens it can pull the cap into the rotor.

Has the bad optis been disasembled to determine the cause of the failures?

Does it have an aftermarket camshaft? Dowel pin could be too long.

 

Time for an opti autopsy.

From the OP, "Now at 58,855 It is bad again???"

Is it bad again? You have a cranks but won't start condition again? No spark and you've got DTCs that point to the opti?

If you're willing to do the work or hire a mobile mechanic I'm sure the collective wisdom of this forum can uncover the root cause.

 

I do not have a problem doing the worl. When each one is replaced they keep saying moisture??? there is a little green on the points but barley anything and as stated the car is store in a dry enviroment and now in a bag.

When the first one went the car ran terrible, than better, would stall then hard starting, etc. But after the first one, it has been car runs perfect and the next morning its dead. Will crank and crank but not even the slightest of hint of wanting to start. After the first I replaced the coil and a few sensors with no luck. had the car towed to the chevy dealer and they said it was the OS. Same thing on 3 and 4 and now 5. I have not taken the car to the dealer for 5 as it is the same senerio and it is getting expensive for them to tell me what I can't belive is correct

tmach

 

I would start with the basics. I would test at this point to see if there is spark with a spark test tool on #3 since it is the easiest to get at. (various shade tree spark tests work too)

I would also scan for DTCs. Do you have any lights on the DIC? SES?

 

I do not accept that the opti has caused this problem repeatedly. I don't doubt that the opti might have been bad in the first instance, but not the second, third, fourth and fifth.

The second-generation, actively-vented optis tend to be immune from the condensation-related failures that plagued the first-gen, passively-vented units, and NONE of them will fail due to non-use in such a short time. A condensation build-up will almost always result in cross-firing (backfiring into the intake, etc) just as though plug wires are crossed, and you report none of that.

Furthermore, I've NEVER heard of an opti that operates flawlessly one day, then won't fire a single cylinder the next morning.

If, and only IF the opti-related DTCs are being set repeatedly, the fault is most likely in the ECM harness connector on the opti, and it was most likely caused by the installer of the first replacement unit.

Get your car to an expert diagnostic technician who knows how to troubleshoot and has the proper equipment to do it well. Then go back to that dealer and retrieve a lot of your mis-spent cash. This is BS.

Live well,

SJW

 

Obviously, this is not normal or acceptable at all.
Something is very wrong here. Either bad parts or bad install procedure.

As mentioned above, you need to find out exactly what is causing this.

I have over 109,000 miles on my LT4 and it still has the factory original Opti.

 

electronic control module ? mounts next to, under coil.

my 96 has been stone cold reliable, opti wise. original (?) opti got new cap and rotor 4 years prior to finally dying at 145,000 miles. when I took the old one apart it was in terrible shape, heavy moist green corrosion everywhere. it was winter, cold and wet, vehicle parked outside in the rain, had aggressively cleaned the engine with a power washer ....everything that you're not supposed to do to an opti car had been done....and still the car had run and run strong.

what I did find was problems with the vacumn harness.

the small hose that brings clean air to the opti had been cut through by the fan belt. (this hose comes off the metal barb on the opti body and runs to the rubber air coupler ahead of the intake manifold). that was the obvious damage.

less obvious were where both hoses ran under the waterpump, under and through various brackets, oil and heat had softened and deteriorated these hoses to the point of failure.

its not enough to merely rehook up the factory vacumn; the harness must be throughly inspected along its entire length.

in my opinion, I don't think the factory vacumn harness is worth replacing; cost and availability issues notwithstanding, you can replace it with much sturdier hose available at any parts house.

other issues include the filter and check valve located in the hose just before the intake manifold; both must be clean, functional, and unrestricted (this hose provides vacumn; it comes off the intake manifold and runs to the 5/16th inch barb on the distributor cap).

the original opti gm a/c delco; the replacement is gm a/c delco; zero problems so far....others who have used various aftermarket units report problems.

good luck; I admire your tenacity




i

 

p,s. where the wiring harness plugs into the opti, there was terrible corrosion, for this short length of harness the dealer wanted $250. found new on the internet for less tha $50. this small harness could be a source of intermittent, repeat problems,

 

I have no warning lights on and I have a handheld code scanner and no code are comming up

tmach

I am going to the dealer tomorrow with some of these comments in hand to have some (not so kind) discussions

 

I cleaned the contacts on the harness and still no luck. Where did you get the aftermarket harness

 

www.eficonnection.com/lt1_pigtails.apx or 814-566-0946 has connectors. You want the 18 inch pigtail from the connector under the FI rails passenger side to the Optispark, about $35 I thnk.