Another Knocker
Thread Starter
Advanced
Joined: Oct 2005
Posts: 61
Likes: 0
From: Oklahoma City Oklahoma
Another Knocker
Hey Guys I'm new here so be easy on me. I just recently bought my 93 lt1 and I must say it's a great car. I have had a little trouble with it just minor things until now and I have researched to see what the problem should be, but I wanted to see what you guys thought. I hear a knocking coming from the motor under slight load from 1500rpm to 2300rpm, on the highway there is no problem. I am guessing it is the Optispark from all of the old posts I have read. I plan on replacing the Optispark with some new wires is there anything else it might be and do I need to buy the cap and rotor also? Thanks for the help.
Race Director
Joined: May 2001
Posts: 14,165
Likes: 9
By knocking do you mean like deep banging, or light pinging? Curious what would make you think opti? Experience has shown time and time again that the opti is always the first culprit for nearly every LT1 problem but it is very rarely the actual problem.
Give us as many details as you can about the problem and we'll be happy to help.
Give us as many details as you can about the problem and we'll be happy to help.
Thread Starter
Advanced
Joined: Oct 2005
Posts: 61
Likes: 0
From: Oklahoma City Oklahoma
It is a deep knocking but only when it is underload,if I lightly give it gas I won't hear any knocking but if i'm a little harder on the accelerator there it is. When I'm sitting at a stop light it will miss on occasion and when I take off it hesitates a little. This only happens in the city, when I'm on the highway everything is running fine I can hammer it and no problems at all. It's almost like the fuel is not being burnt all the way. Does it hurt to drive the car when it knocks? It has puzzled me I don't want to just start replacing parts and it just kills me to take it to a mechanic. Also every now and then when I start it up it hesitates then makes a horrible hammering sound almost like the distributor cap is cracked.
Racer
Joined: May 2005
Posts: 279
Likes: 0
From: houston texas
Originally Posted by ripped_78
Hey Guys I'm new here so be easy on me. I just recently bought my 93 lt1 and I must say it's a great car. I have had a little trouble with it just minor things until now and I have researched to see what the problem should be, but I wanted to see what you guys thought. I hear a knocking coming from the motor under slight load from 1500rpm to 2300rpm, on the highway there is no problem. I am guessing it is the Optispark from all of the old posts I have read. I plan on replacing the Optispark with some new wires is there anything else it might be and do I need to buy the cap and rotor also? Thanks for the help.
Race Director
Joined: Nov 2000
Posts: 17,103
Likes: 39
From: stop the fun suckers
you need to get a steoscope from harbor freight (6 bucks) and listen to your engine at idle.. listen to the oil pan, the valve covers and.. beliveve it or not.. the cat coverters... if the guts inside the converter melt sometimes they knock in weird situations and give people the false belife the engine is shot... just listen and try and narrow your problem down.. if nothing can be heard at idle we can go from there.. but you need to use the steoscope
