Is there an easy step-by-step process for compression testing? I bought the manual but it was very confusing. It says to disable the fuel pump circuit, crank angle sensor and remove the check valve. I have no idea what and where the check value and the fuel pump circuit is.

Please send me a link to an easier step-by-step process to compression testing.

BTW I bought a compression test gage from the local car shop.

Thanks guys.

 

for a aproximate reading. Just pull the EGI fuse under the hood and pull out a leading plug. Put the guage in the sparkplug hole and have someone turn the starter over. This will not give you a very accurate reading but it will tell you if all of your seals are in good working order. Just look for the needle to bounce three times evenly.

 

The check valve referred to is located in the compression gauge itself. Its purpose is to maintain the pressure reading until released by the mechanic. Since these gauges are designed to be used on piston engines this is a desirable feature.

The rotary needs to have all three chambers checked. Doing so with the check valve in place would give you only the maximum reading of any of the three rotor faces. Removing the check valve will allow the needle to rise and fall with each rotor compression phase. You would like to see three even "peaks" or "bounces" of the gauge needle. This would indicate all three faces (hence the apex seals) are in good condition.

Remember one bad apex seal will cause two rotor faces to lose compression. Two bad seals will cause a loss on all three faces. Ideally you would see three momentary rises to near 80 PSIG. Remember to hold the throttle wide open when doing a compression sheck in order to allow the engine to breathe as freely as possible.

 

Is the check value the little button next to the gage stem? If so, can I just hold the button down when testing? Or do I have to pull the button out? If I do pull the button out will the gage still work on regular non-rotory engines?

Which EGI fuse should I pull, isn't the EGI fuse box containing several fuses?

Thanks guys

 

I tried to screw the compression tester to the sparkplug hole however it is not long enough to screw it in. What should I do?