S2000 Under The Hood S2000 Technical and Mechanical discussions.

no compression across all 4 cylinders

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Old Nov 18, 2009 | 01:04 PM
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From: chino
Default no compression across all 4 cylinders

just did a leak down and all 4 cylinders are 80% leaking...
after the leak down no air is coming out of crank case or the head???
what could it be??? been in the shop for the past week...
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Old Nov 18, 2009 | 01:11 PM
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Could be that the test is not being done right. Which one did you do, a real leakdown test? Wet?
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Old Nov 18, 2009 | 01:15 PM
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From: chino
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Originally Posted by INTJ,Nov 18 2009, 02:11 PM
Could be that the test is not being done right. Which one did you do, a real leakdown test? Wet?
pushing air into the head through the spark plug...also did the oil in the cylinders..didnt bring up the compression at all???
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Old Nov 18, 2009 | 01:28 PM
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Originally Posted by Kado413,Nov 18 2009, 05:04 PM
just did a leak down and all 4 cylinders are 80% leaking...
after the leak down no air is coming out of crank case or the head???
what could it be??? been in the shop for the past week...
sounds like the car is not timed correctly, or all valves are bent.
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Old Nov 18, 2009 | 01:34 PM
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From: chino
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Originally Posted by mLeach,Nov 18 2009, 02:28 PM
sounds like the car is not timed correctly, or all valves are bent.
timing is okay...if the valves are bent, would you be able to see they are bent or would I need to pull off the head and put it on a flow bench?
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Old Nov 18, 2009 | 01:40 PM
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does the car run??

you should be able to hear the air easily with that much leakage.

listen at the tail pipe, if you hear air rushing out then its the exhaust valves.
Listen at the throttle body, if you hear air its the intake valves
Listen at the oil cap, if you hear air there its the rings or the headgasket.
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Old Nov 18, 2009 | 02:06 PM
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Originally Posted by wadzii,Nov 18 2009, 02:40 PM
does the car run??

you should be able to hear the air easily with that much leakage.

listen at the tail pipe, if you hear air rushing out then its the exhaust valves.
Listen at the throttle body, if you hear air its the intake valves
Listen at the oil cap, if you hear air there its the rings or the headgasket.
yeah, the car runs...after it starts the first time and you turn it off, every time after you try and start it is very hard to start..

I havent tried to listen out of the tail pipe...
nothing out of the oil cap...I think there was slight air coming out of the throttle body..
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Old Nov 18, 2009 | 02:19 PM
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with 80% leakdown the engine isnt going to want to run... id bet either the cam timing is off or the tester is messed up/done wrong. what are the compression numbers.

are you using the stock ecu?
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Old Nov 18, 2009 | 02:26 PM
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From: chino
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Originally Posted by wadzii,Nov 18 2009, 03:19 PM
with 80% leakdown the engine isnt going to want to run... id bet either the cam timing is off or the tester is messed up/done wrong. what are the compression numbers.

are you using the stock ecu?
hmmmm...

I believe the compression on #1 is 90, and the rest is at 50...

running a aem stand alone..have a 2mm cometic head gasket so I think the compression should be around the 120 mark?
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Old Nov 18, 2009 | 02:51 PM
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my aem was doing that.. it didnt want to restart on a warm start up if it died. i replaced 2 resistors and all was good.

but you should have ~150-180psi i think.. its been a while since i have done a compression test on a s2k w/a thick hg.

but with 90 and 50.. its time for a rebuild, no since in speculating. its got to come apart to fix
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