vainot4u

...Always the best way to start an Opti thread!

Ok so I believe my Optispark is bad on my 94 Firebird Formula. I bought the car back in July sometime and at that time the previous owner had told me he had replaced he optispark, however I think he replaced it with whatever the Auto Zone brand was... ...why I'll never know. I've ran through the test's listed on shbox.com to test the opti, ICM, and coil, and all the test check out - minus the AC Voltage which should be coming while the car is cranking (Port B on the ICM Harness)...or in other words the pulses that trigger the coil to fire.

...Anyhow moving on...

My question is: As I understand the 94 AC Delco Opti is considered the NON Vented style which is the poopy design that GM had to redesign one short year later...sigh...but it is OEM and I've read that's supposed to be best. However, there is an MSD Opti that comes vented with vacuum tubes in the kit (MSD 8381). So the challenge here is do I buy the MSD because it is vented or stick with AC Delco and pray it doesn't get wet?

Also worth mention is that the Delco one is more expensive almost every place I look so another note worthy consideration...

TeeTopZ

iTrader: (8)

You can get the MSD cap for the early opti. It comes with the vent kit. Then just use the AC delco opti, from what I have read it is still the best

nascarnate326

iTrader: (1)

I have had great luck with my Chandler Opti. Some people have bad luck. Take it for what you will but I spent $90 on mine and its performed perfectly. I know Chandler makes both vented and non vented.

I would replace the plug wires while you are doing it. Autozone brand on mine and it runs perfect.

Check out mifbody.com for local help if you need any.

defaultexistence

iTrader: (11)

Advanced auto part "cardone select" all new opti with lifetime warranty $200 here with an MSD vented cap and rotor kit , 2years DD and multiple redlines ,zero issues.

shbox

I would consider the MSD opti a viable option for people that have spline drive optis. It will provide a venting option (of course, just using the MSD cap will too, as previously mentioned). The non-vented GM opti can be had for a reasonable price. You just have to look to find it.

BOLO

iTrader: (40)

In order to utilize the vented GM optispark, you will need to change the cam pin, since the vented opti is pin driven. You will also need a 95 timing cover(big hole in the middle), a 95-up cam sprocket as well. So, it maybe wise just to get the MSD unit,imo.

96capricemgr

iTrader: (1)

This way he could keep it unvented inviting future problems, great idea.


What about the opti seems bad? You think it is a cap or rotor problem? If so get the MSD cap and rotor kit as already mentioned it will add a vent.

If you suspect an optical sensor issue that is a harder decision to make, could do Delco or Chandler and either do the MSD cap and rotor now or wait till you think the cap needs replacing anyway and do it later.

The MSD unit is so expensive, troublesome and lets people cause themselves huge issues with the timing adjustment it should not be a consideration unless you plan on a keyed hub, degreed damper and fabricating a timing pointer and have the pcm editing software so you can verify timing with it.

noice

I have to say I've had the least amount of problems with the original Opti, when I started mixing the MSD Cap and Rotor I ended up with some rubbing on the rotor and a couple of failures.

vainot4u

Thanks for all the replies guys. I am having the car taken into the shop tomorrow, usually I'd undertake this job myself but with it being December in Michigan and no heat in my garage - I'm not really feeling up to it. I "may" go with whatever part they recommend simply because I know this mechanic and I know if it fails he will fix it again at his cost.

The only thing that really indicated that it was the actual optical side of the opti to me was that none of the ignition system was sparking. as I understand it -paraphrased in a way I understood it- if the optical sensor part isn't working correctly, no signal is sent to the PCM telling the ECM/Coil to fire?? When I went through the tests I found that the one AC voltage test was NOT working which was indicative of the opti having failed.

Thanks for suggestion on the plugs and wires, I would do them except I already did this fall when I put my Pace Setter Headers on.

I'll definitely take everyone's advice in mind when I have this done, and share it with my mechanic...until then cheers guys!

RamAir95TA

iTrader: (2)

Avatar thief!

jit11375

iTrader: (1)

fwiw delphi unit can be had for about 360ish....thats what i decided to run a few months back and its still going strong...and came with a 3 year warranty...guys over at cz28 told me it was oem....once again just me .02 cents

shbox

I saw that, LOL.

OP, I'd go with the AC-Delco/Delphi or if you must vent it, put an MSD cap kit on it. Not all "mechanics" know what they are doing in regard to the LT1.

Big Al

iTrader: (1)

Let me add something for the guys running MSD boxes and coils. If a plug wire comes off the MSD will kill the Opti's cap. Make damned sure the plug wires are secured and never remove a wire to check for spark unless you have a grounded old plug on the end.

Al 95 Z28

vainot4u

Ah but mine's bigger

Yeah I am VERY careful about who I allow to touch my car, this mechanic is well known by our family and is trusted...thanks for the advice everyone!

food nd cars

I would recommend taking it apart and putting some loctite for added insurance.