Defective Opti-spark

[eagle6]

Would a bad opti-spark unit cause a rough and low idle on 94 Lt-1? And how do you replace it also and what is involved.

 

[Aaron71771]

That is one symptom of a bad optispark. They are kind of a pain to replace. You have to pull the waterpump and front main pully to get complete access to it. Not anything too major, just lots of stuff to get out of way.

 

[Vettelt193]

Would a bad opti-spark unit cause a rough and low idle on 94 Lt-1? And how do you replace it also and what is involved.

It is a PITA to get to... the after you get the intake duct/MAF, waterpump, belt, and other various stuff out of the way, you still have to get the crank pulley off (which many times is rusted onto the hub)

Search for opti spark in the forums to read all about them/installation.

Usually, when the opti goes the car won't run at all, so your problem may be something else.

 

[SPANISHVETTS]

(which many times is rusted onto the hub)

I never had an Opti last long enough for the pulley to get rusty, but then I only owned the ´93 for 8 months or two Opti´s (which ever came first).

It is really not that bad a job at all. Since you have the front of the motor exposed you might as well check the timing chain.

 

[jmccloud]

Rough, low speed idle

A defective or slightly stuck open or carbon contaminated (causing stuck slightly open) EGR valve will produce the same sympton.