This would be my vote, too. With bad oil rings, as long as the valves are good you will have great compression readings. And guides or seals won't affect compression either, but will dump oil.
Bill Cardell TurboDog's Dad Flyin' Miata 1-800-359-6967 (sales) 970-464-5600 (tech support) www.flyinmiata.com www.fmwestfield.com ________________________________ From: [email protected] [mailto:[email protected]] On Behalf Of Ray Sent: Monday, March 22, 2010 8:13 PM To: Jeff Dooley; Eric McCord; Miata Power Subject: Re: Compression loss? Quite likely the oily plug in 3 is causing severe misfire. Oil would most likely be coming from either the intake valve stem or a frozen oil ring on the piston. ----- Original Message ----- From: Jeff Dooley <mailto:[email protected]> To: Eric McCord <mailto:[email protected]> ; Miata Power <mailto:[email protected]> Sent: Monday, March 22, 2010 6:52 PM Subject: Re: Compression loss? I checked the oil for signs of coolant and the cooling system for signs of oil. Both systems appear to not be mixing. Changed spark plugs and plug wires. O2 is 114 on the LINK with engine idling. Cruising in 4th gear at 3K RPM yields normal O2 readings of 78. The MAP is showing around 55-60 kpa while idling which is much higher than the usual 29 kpa. I pulled the new plugs after letting the engine idle for about 5 minutes. Cylinder 3 plug was wet with oil. The other plugs were black and dry. Performed a few tests with the engine running; Pulled each injector plug and these were the results- Cyl 1 = RPM drops Cyl 2 = RPM drops Cyl 3 = RPM drops only a little Cyl 4 = RPM drops moderately Next I pulled the Plug wires individually while letting the engine idle- Cyl 1 = RPM drops Cyl 2 = RPM drops Cyl 3 = RPM drops only slightly Cyl 4 = RPM drops This is an engine built by The Dealer Alternative about 80K miles ago. It has an FM3 Turbo Kit. Please help! TIA, Jeff On Fri, Mar 19, 2010 at 12:04 AM, Eric McCord <[email protected]> wrote: I had a bad head gasket that was pushing coolant overboard by pressurizing the cooling system. Headgasket is my vote too.... Eric On Fri, Mar 19, 2010 at 2:31 AM, Bob Bundy <[email protected]> wrote: That would be my vote. The last two cylinders could be just pumping charge between the two. ________________________________ _______________________________________________ Miatapower mailing list [email protected] http://list.miatapower.net/cgi-bin/mailman/listinfo/miatapower
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