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Compression test

Bmaughan

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Any particular compression tester would you guys would recommend?
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Any particular compression tester would you guys would recommend?
Any decent quality one should work.. remember it’s not so much about the over all number but consistency between the cylinders. I like to see less than %10 difference from highest to lowest.
 

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A lot of the Automotive testers on the market are just rebranded OTC and it's what I usually try to buy. Cornwell, MAC and even SnapOn just rebrand a lot of non-standard items.
 

ahl395

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The standard one from Autozone has worked for me for years.

As said watch mostly for consistency between cylinders and make sure to do the exact same amount of cranks on each cylinder or it will skew the results.
 
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Bmaughan

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The standard one from Autozone has worked for me for years.

As said watch mostly for consistency between cylinders and make sure to do the exact same amount of cranks on each cylinder or it will skew the results.
If using the starter, it seems like it would be hard to get it exact since it turns over so quickly. Is there a trick?
 

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Bmaughan

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Any decent quality one should work.. remember it’s not so much about the over all number but consistency between the cylinders. I like to see less than %10 difference from highest to lowest.
A lot of the Automotive testers on the market are just rebranded OTC and it's what I usually try to buy. Cornwell, MAC and even SnapOn just rebrand a lot of non-standard items.
Thanks for the help!
 

ahl395

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If using the starter, it seems like it would be hard to get it exact since it turns over so quickly. Is there a trick?
Just push the start button to start cranking, count, and push the button again to stop cranking. It cranks slower than you think once there's no fuel being injected and its not actually starting since it's not actually turning over. You have to disable the fuel pump when doing a compression test.
 
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Bmaughan

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Just push the start button to start cranking, count, and push the button again to stop cranking. It cranks slower than you think once there's no fuel being injected and its not actually starting since it's not actually turning over. You have to disable the fuel pump when doing a compression test.
Gotcha... do you just unplug the fuel pump control module or is there just a fuse that you can pull?
 

ahl395

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Gotcha... do you just unplug the fuel pump control module or is there just a fuse that you can pull?
You can do either one, the fuse is easier though. It's in the engine bay fuse box
 

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If using the starter, it seems like it would be hard to get it exact since it turns over so quickly. Is there a trick?
Since you will have all of the spark plugs out you can hear when it hits compression on the cylinder with the pressure guage in it. Just count like 4 times you hear that cranking sound change, and stop.
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