I've owned my 94 z28 for a few months now and have been happy with it since (even though I miss my suv and loud subs), but recently my LT1 hasnt been running right. I've read on countless lt1 forums and it seems that many people had the same problems have (as far as running rough as bogging), but without a clear solution. I love this car but I dont like driving it now because of the way it runs.
So first off I'm pretty familiar with lt1 engine itself (how it works, the basic layout ect), but I'm no mechanic. I do all the basics myself (oil change, intake piping, fuel filter ect), but I don't have all the tools to do anything major. So after you read my issues please let me know specific tools i'd need to fix it.
***As for the car I'll explain what I know needs fixing and some symptons the car has, so any help would be greatly apprieciated.
So about 2 months ago I drove into a deep puddle and my cold air intake sucked up some water (my heart sank). The next few days I took out/dried the DS spark plugs and changed the oil 2x. It ran badly for a few days but ran fine after that, and now it's worst than ever.
*I can hear vavle ticking when I'm on it (not so much at idle)
*engine boggs, stutters, and shakes at low and high RPM
-runs rich and backfires when I let off after getting on it
-intake elbow is in bad shape (has rips on the t.b. end)
-has about 120K with cheap Valvoline 5w30.
-exhaust leak at the front of the 'replacement cat' (it looks longer and more narrow than an OEM cat)
-had it scanned before the major problems and O2 and knock sensor code are thrown.

***I know that there are ALOT of problems to address, but please tell me its not hopeless. and I know there's many experts here so any advice would be helpfull!!

 

When your intake sucked up some water, did the engine kill? If it did, did it start right back up again, or did you have to dry everything out first?
Since the water was deep enough to soak the intake, it was also probably deep enough to drown your optispark. The engine running the way you describe are classic symptoms of a bad opti, especially under the "flooded" circumstances.

 

That makes sense...and yeah the car was dead until it dried out. There was a total of at least 2quarts of water. (almost felt like the motor siezed) but luckily it started up and ran a few days later. I have the same oil since the 2nd oil change I did, 2 days after it flooded (about 2months ago). Could that eventually cause noisey valvetrain? Could good synthetic oil help this? And as far as the optispark goes I'm interested to see how much my mechanic will charge to change that...Also if you know the lt1,,would it be easier to pull the motor or work on everything in the car?--------

 

Also are there any addatives or better fluids I could use to help the motor run smoother?

 

I just did my opti last week. And based on that, I would guess it would have to be in the neighborhood of $900 to pay to have it done. A stock opti alone is in the $300 range, without markup. So $600 in labor doesn't seem out of line, considering the amount of time it takes to do. That's also based on the hourly rate where you're at. Also, since you have to remove the water pump to do the job, you might as well put on a new one of those. If your engine has the original opti, then it has lived a pretty good life at 120k miles. If the opti has been replaced recently, you could just remove the cap & rotor and clean it up inside. I'm fairly certain yours is now corroded and damp inside, both of which is an ignitions enemy. Because of that, I really don't think your engine runs rough because it needs a "magic additive".
I took a lot of pictures of my project, and am going to post a thread on it once I get it compiled. There's a few "do's and dont's" and "how to's" that are important to know.

 

Thanks Camaro69 for all your input, I'll probly go to my shop and see what they'd charge for the opti and go from there. But if I were to do it how long did it take you to do...and what tools did you have to use to do it. (besides basic wrenches/sockets)...also is that your Blue 69 camaro? cause that thing looks pretty sick.

 

I took a whole weekend on it. But I was being very meticulous and was doing a lot of cleaning, degreasing, and detailing under the hood. I also had to take time to figure out and make a water pump seal installation tool.
And to your last question, yes and thanks.

 

Thnks once again

 

here is a write up i found for you to look at. The opti isnt that bad its just time consuming. The only annoying part is draining the coolant since it can get messy (especially when you pull the tubes off and waterpump) I have a 94z28 as well and if you need any help let me know since i have done this about 4 times myself. In the write up they dont mention this but i removed the passenger side fan to make more rooom.

http://www.lt1engine.com/tech/93-97-...emove-replace/

 

Man, it isnt hard at all to replace the opti but I would also replace the water pump while i was at it so you wont have mess with that area again. Probably change the wires too since the are a ***** to get to. I would say that is your problem. Also i would run 93 octane and good oil. Replace the knock sensor and 02 sensors. You should do all this yourself. A garage will charge you out the rear for something you can do easily in one day. Good luck.