going to check my chevy 5.7L. ...so after removing the plugs and high tension lead and connect the tester on a warmed engine, open the tbi ..when you crank the engine over would't the tbi be shooting fuel into the engine? Never done a compression test on a tbi before.
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if the time ever comes you can't see it, you can lay on your back and do it from underneath.
Maybe, but that bit of gas wont matter...I guess you could hook a jumper switch just to the starter and just crank the engine without the key being on.
Why not just crank the engine over by shorting the relay over at the starter. I realize that disconnecting the harness for the injectors will stop the fuel, but the coil(s) will still be energized. I think some ignition systems might get damaged if they don't have the spark plug installed and grounded.
I think that in all fairness to your cylinders, you should let them know ahead of time so they can study for the test. It's just the decent thing to do. I know I would ... testing them at the last minute, giving them no time to prepare could result in all or most of the cylinders failing the test.
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If at first you don't succeed you do have options ... lower your standards or just plain quit are the two I usually choose from :)
Im not 100 % sure of this , but I think the injectors shut off when cranking at WOT
There are many injected engines that do shut off the injectors if the ECM/PCM has the "Clear Flooded Engine" parameters. Not 100% sure if the 1/2 ton 1988-1995 engines do this or not.
Compression testing should always be done at WOT. I owuld thing that having fuel in the equation might take some of teh accuracy between a dry and wet compression test. Dry showing leaks in the rings and valves, then after introducing some oil into the chamber for the wet test to show any leakage in the valves.
