Zebisko

iTrader: (3)

Hello, new to the boards, and with my recent purchase, new to LT1s as well. I have a 1995 T/A 6-speed black with 99,000 miles. But I have an issue. My car is getting poor emissions and runs fairly rough. I put in new plugs as the old were worn out, but it didn't help much. I plan on replacing the wires, but my service manual tells me I must remove the crossover pipe in the exhaust, so that will have to wait until I can fix my old car. My plan was to take it down and do all of the work it needs done on it (needs a new freeze plug, heater core, front LS1 brake swap, front main seal, those wires, and fluids all around).

I believe the Opti-spark to be on its way out. Is there a way to take it apart and tell if it is bad or not? I am not getting any trouble codes, so it would have to be a visual inspection. I have read some good things on the Dynaspark, Delteq, and LTCC units, but has anyone had bad experiences with any of those? Cheapest places to get things for these cars? Any advice on anything? Thanks in advance.

96LT1355Z28

iTrader: (2)

Mine ran like crap when it even started, my optispark looked fine. I replaced it and the car started right up. It would make the job easier but you shouldn't have to take down the exhaust to do plug wires. Mine was a dual cat car (now has LT hearers) and I don't rember removing the exhaust. Just make sure the new wires are clear from any exhaust components. I recommend getting a good quality brand plug wire, I got a bad set from AC Delco. Many people blame the opti right away and at 99K it's pretty likley (check for leaks at water pump!). I recommend checking compression and for spark at each cylinder for peace of mind before you go throwing $ at it. You also should keep in mind it could be any number of things, O2 sensor false reading, Clogged cat, who knows. I say start as simple as possible, fuel psi, fuel and air filter, make sure all sensors are plugged in w/ a good connector then move on to ignition and exhaust. It is a frustrating process especially when the pcm isn't setting a code, good luck!

96capricemgr

iTrader: (1)

A cap and rotor are VERY likely all you need to fix the opti, it is a distributor and those are wear items and people as a rule neglect them and then are so ******* stupid they blame the design and swear they need one of the "opti eliminators" that actually need half the opti to still function. The thing is if the LTCC or Delteq "fix" the car all they needed was a cap and rotor. I have put about 180K total on my two LT1 vehicles having bought both of them used and the only "opti problem" I ever had was one needed a new cap and rotor at like 190K miles(no idea actual age I bought at 172k) put a cap and rotor on it and now at 220K it is still running fine.
The other one at 96K on the original opti I boght into the "opti is evil and the source of all trouble" stupidity you find on forums and replaced, it was not my problem, made no improvement atall turned out to be an injector was dead, that base is still on the Caprice at 180K total miles, 15K ago I put an MSD cap and rotor on it, all is good.

The Engineer

I think you're on the "right road" w/ plug wires next. As pointed out above, after the wires should probably be the Opti cap and rotor only. However, you can look the Opti over for wear (loose shaft, Etc.) once you get it out and apart. If you were missing any high/low resolution pulses from the Opti (major problem) you would be getting a DTC.

Also, you may want to pull some easy plugs and read them to see how they look (brown/tan on the ceramic) to see if you have any problems that way. Next would be someone with a scanner to look at all the PCM parameters.

WD

Zebisko

iTrader: (3)

Well, I was planning on looking at the cap and rotor, and most likely replace them, but I wanted to know if I could actually tell if the optical sensor is bad. I have a theory that it just needs a tune-up and cat, but I want to know if the distributor is the cause while I have everything apart, as I only want it apart once. I was also thinking that since my front main is bad it could be slinging oil on the distributor. Well, I will go ahead and do those wires and what-not, and see where that leads me.

The Engineer

The optical module "within" the Opti distributor generates both high and low resolution pulses (two different signals) that are send back to the PCM. If either of those pulses are missing you'll have a DTC. Additionally, if you loose the high, the car will hardly start or run. Without the low, I don't believe the car will run.

Also, you can have the Opti rotor getting loose and have a random high RPM miss.

WD