It could be that the guage is not accurate since im getting the same on all cylinder
Engine compression
Thread Starter
Heel & Toe
Joined: Sep 2007
Posts: 17
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St. Jude Donor '12-'13-'14
Thread Starter
Heel & Toe
Joined: Sep 2007
Posts: 17
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St. Jude Donor '12-'13-'14
Pro
Joined: Aug 2007
Posts: 544
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From: Oxnard Ca
No way would you be leaking down that much. Get a new guage tomorrow, retest and repost. Hell I think most places even rent them. Let us know what you come up with on a recheck and we can get some experts in here to go further.
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Joined: Nov 2007
Posts: 57
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From: Port Angeles Wa.
Your miles away from the dreaded 100 LB mark, If compression is within 10 to 15% highest to lowest, motor should Idle sweet, like new. run it! No excess oil consumption, blow by, Bottom end noise right? Why the compression check, looking for a problem, or just curios?
Thread Starter
Heel & Toe
Joined: Sep 2007
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St. Jude Donor '12-'13-'14
Replaced the oil sensor about three weeks ago and shortly after it was misfiring a little bit so I started to troubleshoot by removing a spark plug to see if there was something there and the first spark plug wire that I pulled on came apart with very little effort. Then found that 4 other wires were also damaged. So I decided to replace the spark plugs as well since I bought the Vet last May and don’t know how many miles are on it.
Safety Car
Joined: Jul 2004
Posts: 3,904
Likes: 28
From: Vancouver Washington
I'm getting ready to do that too. What is the correct way to do the test. I was just going to pull all the plugs, install the compression guage and roll it over with the starter a few times on each cylinder.
Former Vendor
Joined: May 2006
Posts: 718
Likes: 1
From: Riviera Beach FL
To get an accurate reading you need to remove all the spark plugs and have the throttle plate wide open. Your readings are not bad, actually with all your readings that close together they are pretty good. Compression testing is really only good for testing pressures between cylinders. If you are really concerned you need to do a leak down test. I would not loose a lot of sleep over this. As Blowa-z states you are a long way from the 100 psi which is what GM considers the low limit.
Thread Starter
Heel & Toe
Joined: Sep 2007
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St. Jude Donor '12-'13-'14
To get an accurate reading you need to remove all the spark plugs and have the throttle plate wide open. Your readings are not bad, actually with all your readings that close together they are pretty good. Compression testing is really only good for testing pressures between cylinders. If you are really concerned you need to do a leak down test. I would not loose a lot of sleep over this. As Blowa-z states you are a long way from the 100 psi which is what GM considers the low limit.
Drifting
Joined: Jul 2006
Posts: 1,700
Likes: 60
From: Springfield IL
Since when is 165 bad?
My engine, at 90/130psi ran like a dream, and only ate a quart every 2500 miles of HARD driving
What was your first puff reading? How many puffs to get to 165? Do it again with throttle open. Measure the first puff, then check after 5 puffs.
My engine, at 90/130psi ran like a dream, and only ate a quart every 2500 miles of HARD driving
What was your first puff reading? How many puffs to get to 165? Do it again with throttle open. Measure the first puff, then check after 5 puffs.
Thread Starter
Heel & Toe
Joined: Sep 2007
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St. Jude Donor '12-'13-'14
With the throttle fully open it was much better. the 5 puffs were as follows. 140, 160, 180, 190, 205. Im feeling much better about this. Tomorrow it gets new spark plugs and new wires and drive this babe again.
Thank you all for the help.
Thank you all for the help.
Le Mans Master
Joined: Mar 2002
Posts: 5,955
Likes: 161
From: PNW
Yes ... throttle wide open is always the best way to do compression tests, and crank engine until the gauge stops climbing. Also, some engine manufactures suggest doing the compression test while the engine is warm if possible. Might make a slight difference.
