Compression test questions

[GNandTTA]

Just did a compression test on my GN. Engine was semi warm and I had the throttle cracked open. I just disconnectd the ECM orange wire by the battery. Doesn't that shut off the injectors as good as pulling the injector fuse(s)? The compression #'s I got were not as good as I hoped. All 6 were between 100 and 115. Seems a little low. Maybe the compression gauge is bad? I am chasing a low vacuum condition. Vacuum fluctuates between 12 and 15 at idle. Already checked all the vacuum lines with a mityvac.

 

[turbobuickman]

Those are low numbers. They should be around 145 to 150 I think. The good news is since theyre all pretty equal it might be the gauge. How many miles on the engine? Ever had any valve work done? You said the engine was "semi-warm", try bringin it up to "fully-warm" and retesting.

 

[441120]

vacuum

Idle vacuum of 15" is Ok. I'd try another compression tester.