How to do a compression test LT1
Thread Starter
Racer
Joined: Jul 2019
Posts: 399
Likes: 37
From: Kansas City Metro Area, Missouri
How to do a compression test LT1
Does anybody have a link to a writeup on how to do a compression test on the LT1? The book mentions some things I don't understand. Is it the same as any car? How do I handle the optispark? Thanks!
The things from the book were what does it mean by
"remove the "BAT" terminal and four terminal connectors from the optispark".
The things from the book were what does it mean by
"remove the "BAT" terminal and four terminal connectors from the optispark".
Safety Car
Joined: May 2001
Posts: 4,741
Likes: 1,639
From: Fairfax Virginia
Before doing the Compression test be sure to charge the battery up and keep it charging while you are testing the engine's compression.
Also be sure to secure the throttle body wide open so the maximum air can get through it.
To get a good reading of your engine everything needs to be consistent. While you are at it you might try getting some oil ready for the wet version of the test. I use a small syringe to squirt oil into the cylinder before the wet test.
Don't forget the Anti-seize on the your spark Plugs when you put them back.
Also be sure to secure the throttle body wide open so the maximum air can get through it.
To get a good reading of your engine everything needs to be consistent. While you are at it you might try getting some oil ready for the wet version of the test. I use a small syringe to squirt oil into the cylinder before the wet test.
Don't forget the Anti-seize on the your spark Plugs when you put them back.
Team Owner
Joined: Aug 2004
Posts: 21,543
Likes: 3,216
From: Park City Utah
It's the same as any car. Don't really need to do a wet (oil added) test. If it has poor compression, adding oil isn't fixing the problem.
Remove all the plugs. Disconnect the opti harness under the left injector cover. Hold throttle wide open. Crank. Write down the numbers. Look for less that 10% variation.
Remove all the plugs. Disconnect the opti harness under the left injector cover. Hold throttle wide open. Crank. Write down the numbers. Look for less that 10% variation.
Thread Starter
Racer
Joined: Jul 2019
Posts: 399
Likes: 37
From: Kansas City Metro Area, Missouri
It's the same as any car. Don't really need to do a wet (oil added) test. If it has poor compression, adding oil isn't fixing the problem.
Remove all the plugs. Disconnect the opti harness under the left injector cover. Hold throttle wide open. Crank. Write down the numbers. Look for less that 10% variation.
Remove all the plugs. Disconnect the opti harness under the left injector cover. Hold throttle wide open. Crank. Write down the numbers. Look for less that 10% variation.
Got it done. Getting to cylinder 8 was the biggest problem. Results came out with 6 cylinders at 170, one at 175 and 1 at 180.
