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Opti spark question for Vettelt193 (or anyone )

Cruise

Active member
Joined
Jan 24, 2002
Messages
38
Location
Barrie, Ontario, Canada
Corvette
1994 coupe
I am trying to determine if I need to replace my Opti spark on my '94 Automatic, after 80,000 miles.

The engine is idling irratically, the drop down gear won't work and my ASR service light is on.

I just replaced the TPS and ECM and had all the codes cleared, but the above issues are still occuring.

Any idea what the job is worth and how difficult it is to do?
 
I replaced my opti on my 92, It was backfiring and spark knocking, The job is not too bad you have to remove the damper pully and the water pump I replaced pump also. And plug wires while everything was open. I had about 500.00 in parts and a saturday. Hope this helps.
 
Both waterpump and opti replaced on the 94 at 79600 miles. Its probably time for you too.
 
Thats good for a 94-96 vette. The 92-93 optic spark is different, it has no vaccum plug. In corvettecenter.com it shows on how to create a vaccum line with "T" connectors
 
sorry it took me so long, I went out of town for the long weekend....

My first question is, did all the problems start at the same time??

The only real PITA with the job is the crankshaft pulley... if yours is rusted together, you will have a heck of a time getting the pulley off of the hub without a car lift (it just seems like you need leverage from under the car to get the two peices apart)

-Did you clean out the throttle body when you did the TPS? did you change the TPS because it was running bad? by drop down gear do you mean it won't kick out of over drive? (because there ins't enough power)

-Before you go nuts and change the opti, check all the spark plug wires, make sure none are loose... also, disconnect the battery for about 5 minutes, then re-connect... see if it helps... write back and i can help once the problem is more clear.
 
Crankshaft pull...

When I changed my opti I didn't remove the pully at all. I used a puller to pull the pully..... eh hum

I pulled the crankshaft balencer and hub just far enough to remove the opti. When doing this the balancer is darn near on top of the stearing rack. I fab'd up my own pully to seat in the bell of the pully. However, I have read on CAC that the standard pully can do the job.

Over all the job is not all that bad. Just don't back the balencer into a position that you can't remove OR use it as the installer.

My 2 cents.
 
I appreciate all of your responses.

All of the issues that I mentioned seem to have happened all at once, after a long road trip from Toronto to Boston last year.

When I am driving the car, it will up shift normally, but once I pull out on the highway and accelerate, it won't "downshift" to provide the extra power.
If I shift manually, it is fine but that isn't always feasible once I start to slow down, since it won't drop down to the proper gear.

I did check the spark plug wires and they are all on tight.

Another thing that has just started to occur, is my battery is going dead after a couple of days.
I've checked the obvious things ( interior lights etc ) and I put a call into the garage that changed the TPS and the computer to see if they know why it may be doing it also.

When I first got the car in '96, I had to disconnect the day time running light plug, because it was killing the battery also.
I'll have to look a little closer and see if this new issue is related.

Another question that was asked, regarding the throttle body being cleaned.
Are there any do's and don'ts when cleaning it?
I did try to clean it last year and I am wondering if I may have made it worse.
 
Have you ever changed the tranny fluid? If you haven't, get that done first... it needs it after 80k. The entire problem with rough idle and bad shifting could be tranny related. The power drain problems are not for me to answer, I have no idea:( Your vette has daytime running lights? maybe the previous owner did a bad job of installing and it is causing your electrical problems?

Get throttle body cleaner, spray it on a rag and start wiping out the TB... open up the TB and make sure you get where the blades touch the sides... if it is bad, it will take more than one rag... keep going until you wipe it clean.
 

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