Compression Check Tip

Compression Check Tip

When doing compression checks, you should always ground the secondary coil outputs for two reasons.
1. because without the load of the spark plugs the voltages go much higher and can cause damage to the ignition module, and
2. because the other 7 cylinders are pumping through the spark plug holes any raw fuel they can find. Sparks are not a good idea. Lit an engine on fire this way in my youth, it makes your heart go pretty fast finding the fire extinguisher!


>I just performed a compression check on all 8 cylinders and all showed
>between 80 - 90 psi - huh.... that's really low??? I got a second gauge -
>same results.

Could it be that you forgot to hold the throttle wide open while doing the compression check? I've seen cases of near heart failure brought on by doing that.

-John White-

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