Cranking partially disassembled engine for compression test

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Sep 3, 2010 | 01:09 PM

Travis Johnson

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From: Dayton, OH

Cranking partially disassembled engine for compression test

I have my engine torn down a bit and want to run a compression test while I actually have some room. The intake manifold, exhaust manifolds, and water pump are all off. Most of the wiring harness is disconnected. I have the fuel rail tied off to the side.

Would there be any problem just pulling the IGN fuse and cranking the engine for a compression test? Or do I need to hook some things back up?

Sep 3, 2010 | 01:12 PM

SS Junk

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You should encounter no problems. Just make sure any hot wires have been isolated. You have to pull the fuel pump fuse as well.

Sep 3, 2010 | 01:16 PM

PitchblackC3

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From: Noble, OK

Bleed off any pressure on the fuel rail or the injectors will start spraying everywhere.

Sep 3, 2010 | 01:24 PM

Travis Johnson

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And alternator is also off. Forgot about that.

Sep 3, 2010 | 01:30 PM

fergymoto

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You'll be fine. I have compression tested engines on the engine stand before.

Sep 3, 2010 | 02:22 PM

razor02097

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The PCM/IGN fuse disables fuel and spark. You should be fine.

Sep 3, 2010 | 02:22 PM

1badzee

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From: SFL

You'll be fine.. Even if the harness was out, just jump the starter and do it that way. Quick and easy way if you have some jumper cables and battery and you want to check compression on a junkyard engine.

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