Looking for instructions for testing compression...

C@lvin · Post by **C@lvin** » 19 May 2010, 09:22

I did a forum search but couldn't find anything. Could someone provide "how to" instructions or post a link to a procedure description? I picked up a compression gauge at Harbor Freight but the instructions that came with it, among other things, say it takes two people.

Also......I would appreciate instructions on a "leak down" test which I assume would use the same pressure gauge.

Post by **charlyW** » 19 May 2010, 09:27

Best to buy a compression tester that screws into the head and not a push on type as push on ones arent very accurate. These are the instructions found in the UK Spec Haynes Manual

: compression test.JPG (130.11 KiB) Viewed 4029 times

Post by **jblackburn** » 19 May 2010, 09:28

Here's a great article that will probably explain it to you more in-depth than I can, with lots of pictures. Pictures are good!

http://www.automedia.com/Engine_Compres ... 050801cc/1

The link to page 2 is kinda hidden, but you'll see it.

Post by **JDS60R** » 19 May 2010, 09:53

Here is another one for compression

http://www.volvospeed.com/Repair/compression_test.html

For leakdown you need a different testing rig. If you have two guages and a pressure regulator you can use the hose from the compression tester without the valve. Its better to have both testers. The leakdown tester helps pinpoint issues better than the compression guage. But both are very useful in diagnosis.

C@lvin · Post by **C@lvin** » 19 May 2010, 13:32

Great information. Thanks.

If it's not already there (I couldn't find this information searching the forum) it might be helpful to put this thread in the repair database.

Alecw81 · Post by **Alecw81** » 16 Mar 2011, 22:23

Just picked up a compression tester today, is it possible to do this solo?

zanzabar · Post by **zanzabar** » 18 Mar 2011, 23:36

Alecw81 wrote:Just picked up a compression tester today, is it possible to do this solo?

If you can get the pressure gauge sitting in a position that you can see from the driver's seat, sure. But typically as the engine chugs you'll find that the gauge will shift or rotate or whatever and you won't be able to see it clearly. You really need someone else there to read the numbers for you or to crank the engine while you look at the gauge.

Post by **jblackburn** » 18 Mar 2011, 23:43

Sure. My gauge holds the highest reading like a tire gauge until you reset it.

Do the test on a warm engine. Disable the fuel injectors and spark. Then hold the throttle wide open each time and let it crank through a few cycles (about 8 seconds/cylinder or so).

Alecw81 · Post by **Alecw81** » 28 Mar 2011, 16:28

Easiest way to disable the injectors?

I'm guessing disconnect like I did for the PCV fix, but is there something quicker?

Post by **jblackburn** » 28 Mar 2011, 16:55

Yep; you'll be done with that in under a minute. Just pop off the metal cover and squeeze the connector on each one.