Compression testing

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May 3, 2009 | 08:22 AM

99RTA

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Compression testing

Can someone tell me which relay or fuse to disable so i can crank the engine over with out it starting. I want to test compression in a cylinder.

I have one cylinder that the threads on the spark plug are oily. I think its causing a misfire at idle. The plug doesn't really look fouled though just oily threads. Its number 8. I also notice the engine has a funny knocking noise when it misfires at an idle but only if its in gear. If i give it any throttle the knock goes away??? odd huh?

May 3, 2009 | 03:19 PM

NVR2MCH

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I got the same problem. My 7 is missing and 8 starts after 7. At idle its bad and sounds worst then when im driving or on the gas. Ive posted a thread on the canadian forum, let me know if you figure something out, ill do the same.

May 3, 2009 | 05:05 PM

LS6427

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When I had a leakdown check done years ago the shop pulled the fuel pump fuse, they turned the enigne over for a couple seconds, then did the test.

May 3, 2009 | 05:15 PM

slayerized6

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pull fuel pump fuse and unplug the 2 main coil harnesses.

May 11, 2009 | 10:56 AM

Rhedalert

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I just recently did a compression test. All I did was pull the PCM power fuse. Done.

May 12, 2009 | 07:14 PM

99RTA

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What numbers did you get? All mine are around 160...all of them!

May 12, 2009 | 09:37 PM

Rhedalert

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Mine were all between 145-155 psi. Motor was cold and hadn't been run in a week, and I forgot to open the throttle when cranking.

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May 13, 2009 | 06:24 AM

TedsB4Csled

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I just disconnected the 2 coil pack harness. There's one large connector on each side, right in the middle of the valve covers. I also removed the fuse to the fuel pump. Just like slayerized6 said. ...and block open throttle.