Hello and thank you for reading. I have a 1992 Corvette, ZF-6 speed transmission, LT1 engine, 105k miles. I will attempt to provide as much detail to my problem as possible, which I warn you will be a long post. I'll start at the beginning....

6 weeks ago, I was out for a drive and after a burst of acceleration, my car lurched suddenly. Immediately afterward, I smelled anti-freeze and smoke began pouring out of my hood. I pulled over and my upper coolant hose had a large tear with anti-freeze spewing out! It got everywhere fast. My father helped me get it home with a duct tape bandage (I know, bad idea, but if you knew my father you wouldn't argue with him...). Anyway, I replace the damaged coolant hose and added some coolant. However, the car is now running very rough and with a severe loss of power. My guess is coolant has partially contaminated my optispark distributor causing mis-firing.

Since the thing isn't running that great, I decide to replace various items. I replaced all my coolant hoses with new ones, replaced all the spark plugs and spark plug wires, and the serpentine belt. After this chore was completed, I started up the car and it appeared to be running fine after the initial startup. I decide to drive it and unfortunately after about 100 feet, I notice something peculiar with my sensors. My digitaltemperature sensor reads 110 degrees, but my needle temperature reads around 250! The car immediately begins running extremely rough after it approaches 260. Again, my digital reads way different than the needle. I pull back into my driveway and turn it off. The coolant in the reservoir is fine, no boiling even. There are no coolant leaks that I can identify. The car is now running rough almost all the time, it vibrates the whole car terribly.

I have investigated one of two temperature sensors (my Chilton's manual doesn't tell where the other one is!), and I know at least one of them (the one attached to the water pump) is working normally based on the ohm testing we ran on it.

Here are my questions (if you made it this far, I want to hug you):

Is my Optispark permanently damaged or could it be the cause of the rough running?

Could a bad temp sensor result in my computer attempting to compensate which would cause the rough running?

Anyone know where the sensor is that connects to the needle gauge for the temperature on the dash display?

Again, any advice is greatly appreciated. This is my last attempt before taking it in to a shop, which I don't want to do ($$$$$$$$$$$$$$$).

 

Sensors! That's what deals me a tough blow. I just know some of the basics, and it sounds to me like you're on the right track.

 

The one in the passenger side head is for the needle.Have you took off the cap from your optispark and dried it out?

 

Can the cap to the opti be removed without removing any other parts?

 

Fully automatic assault wallet [sm=shootshoot.gif][sm=violent053.gif], pumpin' a volley downrange. Time to drop in a full magazine (better make it a banana clip)...

 

Bye the way welcome to CF

 

Best I can remember you have to take off water pump.

 

[sm=roll.gif]that makes me feel better.....

@ repo: Thanks for the welcome.

 

Okay. This was your first attack. Why did you think this? Did you do anything directed to confirm this?
isn't after the boil-over? Or was it running bad BEFORE the B/O???

This second Q is the critical Q... How was it running before?

EDIT:
If it was running good before, then you have fouling from coolant residue, or motor heat damage, or both.

If it was running bad before, we gotta' start from scratch - air, fuel, fire.

 

Hello,my friend.Considering the high miles on your car,have you thought of giving it a complete tune up? You know,the whole shebang? Right now it's possible your opti-spark could be water logged.I say replace it,along with putting a new water pump in since you have to remove the old one to get to the opti-spark.Do all that as well as your plugs and wires and do a radiator flush and,well,but I go on.You get the idea.Check everything including all your sensors and replace them as needed as well.You never know,it might end up running a lot better than before.Hope this helps and welcome to the forum.Good luck.Your friend,Joe.