compression - NoPistons -Mazda Rx7 & Rx8 Rotary Forum

2nd Generation Specific 1986-1992 Discussion


Old 02-08-2007, 05:07 PM
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Hello, I have an 86t2 s4 w/rtek1.7 720's, walbro, intake, exh., ported wastegate, and all the emissions removed also tb mod. I just put the motor in a few days ago it was used out of an wrecked 86t2 the engine only has 42000 miles on it. the engine is now in my 86 gxl shell i have the wire harness, all sensors,complete drivetrain, and new rtek ecu.I did all the wire changes needed and checked them all i also made a code checker and its not showing any thing wrong. I think it could be heavily flooded Ive tryed all the simple ways of unflooding and i trys to start but will not. pull start maybe? I have spark and good spark plugs.

I did a compression check w/piston type i got roughly 60,60,60 then 105 for total in the front and 60,60,80 then 115 rear. I know the 3 strokes should be close together is this too much of a difference in the rear? please gimmie some help with this thanks.
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Old 02-08-2007, 05:51 PM
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Old 02-08-2007, 05:52 PM
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it looks to me like you have low compression
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Old 02-09-2007, 12:19 AM
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roger that JW...

my 86 with 147k has about 90 90 90ish compression (might be 95 but not quite over 100) with a closed throttle.

now I'm not completely sure about this one, and I'd hate to be the one to point you in the wrong direction, but this may be a good time to give the ol ATF fix a try. anyone else?

before you do though, was your foot to the floor when you did the check? check and see if there is anything that might obstruct flow of air/fuel into your combustion chambers, got an O-ring on your compression checker? did you have it screwed in good and tight? before we scrap the motor do your homework, double check everything and try again. let us know.
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Old 02-09-2007, 08:05 AM
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Those compression numbers are definitely low. If you suspect flooding, go ahead and pull the injector fuse and all the plugs and crank it over a few times.

ATF might be a good last resort after you confirm the compression numbers.
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Old 02-09-2007, 11:20 AM
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u could try pull starting if u think its really flooded....
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