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Old 01-12-2017, 06:58 PM   #9 (permalink)
Cyborg ECU
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Join Date: Mar 2011
Location: Coastal Southern California
Posts: 6,297

Black and Green - '98 Honda Civic DX Coupe
Team Honda
90 day: 66.42 mpg (US)

Black and Red - '00 Nashbar Custom built eBike
90 day: 3671.43 mpg (US)
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Originally Posted by Xist View Post
Costco replaced my battery for free yesterday and a friend helped me do a compression test. YouTube mechanics said 5-10 seconds, so she did it three, and we got 140, 140, 130, and 130 (Difference: 10, 7-8%). I saw more people saying 5-10 seconds, so I rented the gauge again, drove twenty-five miles to warm the engine, and then realized I was out of time, so I drove straight to my first client's house wearing a t-shirt, shorts, and ratty old shoes instead of a polo, dress pants, and nice shoes. Today I was running out of time again, so I just drove six miles to Costco for gas. I came home and got:
Five seconds: 135, 141, 151, 149 (Difference: 16, 10%)
Ten seconds: 154, 154, 159, 166 (Difference: 12, 8%)
Ten seconds with oil: 166, 172, 174, 181 (Difference: 15, 9%)
Here is my compression test:

Also, I quoted my Honda FSM as saying "compression should be 184psi (nominal), 135psi (minimum), and no variation greater than 28 psi between cylinders."

Your numbers appear acceptable, though only minimally so in the five second dry test.
See my car's mod & maintenance thread and my electric bicycle's thread for ongoing projects. I will rebuild Black and Green over decades as parts die, until it becomes a different car of roughly the same shape and color. My minimum fuel economy goal is 55 mpg while averaging posted speed limits. I generally top 60 mpg. See also my Honda manual transmission specs thread.

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Xist (01-13-2017)