Low Compression in two cylinders - Club4G Forum : Mitsubishi Eclipse 4G Forums - 2006-2012 Eclipse Authority

dhaliwalmanvir · December 29th, 2011, 03:17 AM

Ok so I have got 2007 GS. My car engine vibrates a lot so I took it to a mechanic. He said it might be because of a bad park plug. But then he checked th compression and he found out that its really low in two cylinders. He said the copmression should be around 160 but I have got only 6 in one and 90 in the other one. The other two cylinders are good and they have compression of 160. So he said the only way to fix it is to replace the whole engine which is quite costly. Any suggestions?

Daxenth · December 29th, 2011, 03:41 AM

gasket check

MFTK · December 29th, 2011, 04:14 AM

Yea. Check ur gasket. If its good. Sry

FeaRlezZ · December 29th, 2011, 07:38 AM

how many miles r on ur car ??

did he do a wet test as well ?? that will atleast eliminate worn rings as the problem.

but ya it could b anything from gasket, valves, worn or damaged piston and rings, lands, etc. . .

Fizzix · December 29th, 2011, 10:16 AM

Which cylinders were low? If the problem cylinders are adjacent to each other then check to see if the head gasket is good.

How clean do the oil & coolant look? Any indication they might be mixing?

NitroGlisson · December 29th, 2011, 11:04 AM

Check the oil and make sure it isn't light brown and frothy...indicates bad head gasket and water getting into oil. If you see that do not drive it! Also check the radiator with the cap off and the engine running...if you see bubbles...bad head gasket and compression leaking through the head gasket into the water jacket. Either of the above...just have the head gasket replaced.

If not head gasket then the rings are shot...I would buy 1 mm-over pistons and set of rods and have the engine bored and rebuilt. Here is your chance to build the lower engine for future power if that is what you want to go for.

Just realized that you have the 4-banger....not sure rods would be neccessary...need to ask someone who knows. The cheapest way out if it is the rings is to just have it honed and add new rings but that still requires major work by a machine shop.

Clovisman · December 30th, 2011, 06:08 PM

Holy-shit 6psi in a cylinder... that cylinder is dead!!

If you have a cylinder with only 6 psi of pressure you should have blue smoke pouring out of the exhaust. If you don't have any smoke coming out of the exhaust then you're lucky, you'll be looking at a head gasket.

deprydation · December 31st, 2011, 08:57 PM

Good article to check for a head gasket leak.

Blown Head Gasket Diagnostic - Tricks Of The Trade - Import Tuner Magazine

December 29th, 2011, 03:17 AM	#1 (permalink)
dhaliwalmanvir Junior Member Join Date: Jun 2011 Vehicle: eclipse gs 2007 Posts: 11 Rep Power: 1	Low Compression in two cylinders Ok so I have got 2007 GS. My car engine vibrates a lot so I took it to a mechanic. He said it might be because of a bad park plug. But then he checked th compression and he found out that its really low in two cylinders. He said the copmression should be around 160 but I have got only 6 in one and 90 in the other one. The other two cylinders are good and they have compression of 160. So he said the only way to fix it is to replace the whole engine which is quite costly. Any suggestions?

December 29th, 2011, 04:14 AM	#3 (permalink)
MFTK Got Stance??? i dont :( Name: Dann Join Date: Apr 2011 Location: LongIsland NY Vehicle: 2009 Eclipse GT Posts: 1,464 Rep Power: 3	Yea. Check ur gasket. If its good. Sry __________________ http://club4g.org/board/members-ride...tml#post603414 http://www.vhoist.com/ride/102112

December 29th, 2011, 07:38 AM	#4 (permalink)
FeaRlezZ tUNED. Name: Brian Join Date: Sep 2010 Location: Boston, MA Vehicle: 2009 4G69 Posts: 3,007 Rep Power: 5	how many miles r on ur car ?? did he do a wet test as well ?? that will atleast eliminate worn rings as the problem. but ya it could b anything from gasket, valves, worn or damaged piston and rings, lands, etc. . . __________________ AEM FIC / UEGO Wideband + POD / Custom Bolted

December 29th, 2011, 11:04 AM	#6 (permalink)
NitroGlisson Soon to be SC'd :) Name: Don Glisson Join Date: Sep 2009 Location: Raleigh, NC Vehicle: 2008 Eclipse GT Posts: 25,383 Rep Power: 30	Check the oil and make sure it isn't light brown and frothy...indicates bad head gasket and water getting into oil. If you see that do not drive it! Also check the radiator with the cap off and the engine running...if you see bubbles...bad head gasket and compression leaking through the head gasket into the water jacket. Either of the above...just have the head gasket replaced. If not head gasket then the rings are shot...I would buy 1 mm-over pistons and set of rods and have the engine bored and rebuilt. Here is your chance to build the lower engine for future power if that is what you want to go for. Just realized that you have the 4-banger....not sure rods would be neccessary...need to ask someone who knows. The cheapest way out if it is the rings is to just have it honed and add new rings but that still requires major work by a machine shop. __________________ Mods: Nitro's Little Girl With Attitude Last edited by NitroGlisson; December 29th, 2011 at 11:08 AM.

December 30th, 2011, 06:08 PM	#7 (permalink)
Clovisman Senior Member Name: John Join Date: Oct 2008 Location: Clovis, NM Vehicle: 2007 Eclipse GT Posts: 2,045 Rep Power: 6	Holy-shit 6psi in a cylinder... that cylinder is dead!! If you have a cylinder with only 6 psi of pressure you should have blue smoke pouring out of the exhaust. If you don't have any smoke coming out of the exhaust then you're lucky, you'll be looking at a head gasket. __________________ 2007 Eclipse GT=Sunset=Auto--20% Tint=Injen CAI=RIPP Long Tube Headers (Jet-Hot Coated)=RIPP High Flow Cat=RIPP BRAT Box=Magnaflow Cat Back Exhaust=Energy Motor Mounts=Ingalls Stiffy=Megan Coilover Suspension=Progress Rear Sway Bar=SP Performance Diamond Cut & Slotted Rotors=EBC Yellow Stuff Kevlar Pads=Diamond Lower Grill=Konig Illusion Wheels=BF Goodrich G-Force Super Sport Tires

		Club4G Forum : Mitsubishi Eclipse 4G Forums - 2006-2012 Eclipse Authority > General Forums > General 4G Eclipse
Low Compression in two cylinders

December 29th, 2011, 10:16 AM	#5 (permalink)
Fizzix Member Name: Stephen Join Date: Apr 2011 Location: Virginia Vehicle: 09 Solar(Y19) Eclipse GS Posts: 59 Rep Power: 2	Which cylinders were low? If the problem cylinders are adjacent to each other then check to see if the head gasket is good. How clean do the oil & coolant look? Any indication they might be mixing?

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