Low Compression all 4 Cylinders - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

240sx_LokiS14 · 12-13-2012, 02:57 AM

So i took my car to a friends shop to have them compression test it. reason was that at times when i drive it. It will bog under load and the rpm pick's up really slow i can hear the turbo spool and everything but the car just doesnt wanna go but then after a little while all the power will come back. This is while im driving this happens once in awhile but i would check my spark plugs n they would be black AF and i would switch them out and it would run fine..but i notice everytime i switch my spark plugs it doesnt act up until later on down the road..n theirs no type of smoke comming out my tail pipe.
any ideas?

My reading's were.
1st:110
2nd:110
3rd:110
4th:90

waxball88 · 12-13-2012, 03:11 AM

Well for starters it seems like you need a rebuild. Thats VERY low compression far out of factory spec. If your car has black plugs, and bogging, i'd bet your tune is very rich. Do you have a wideband in car?
Running rich for extended periods of time will lead to the cylinders being washed causing ring wear, which seems to be what the deal is for you.

240sx_LokiS14 · 12-13-2012, 03:19 AM

Quote:

Originally Posted by waxball88

Well for starters it seems like you need a rebuild. Thats VERY low compression far out of factory spec. If your car has black plugs, and bogging, i'd bet your tune is very rich. Do you have a wideband in car?
Running rich for extended periods of time will lead to the cylinders being washed causing ring wear, which seems to be what the deal is for you.

mhmm..that sux. nope i do not have a wideband. theirs no way to save it now is there?

waxball88 · 12-13-2012, 03:20 AM

Nope.
Grab the mad scientist so you can rip apart the block to replace those piston rings you fried.

240sx_LokiS14 · 12-13-2012, 03:22 AM

Quote:

Originally Posted by waxball88

Nope.
Grab the mad scientist so you can rip apart the block to replace those piston rings you fried.

LOL well guess its time..thx for the input man

240sx_LokiS14 · 12-13-2012, 03:40 AM

Quote:

Originally Posted by waxball88

Nope.
Grab the mad scientist so you can rip apart the block to replace those piston rings you fried.

4got to tell u i have no smoke cmon out of my tail pipe..is that normal? i thought when ur rings went bad u would get sum kinda smoke out of ur tail pipe?

Croustibat · 12-13-2012, 04:31 AM

Did you do your test with a fully charged battery and the throttle wide open ? If not, do it again like that (and pull fuel pump fuse and ignition power transistor first) .

If you want to confirm the problem comes from the rings, do the compression test again but pour a spoon of oil in each cylinder before testing. If that is enough to get high compression again, then your rings are fubared.

If the rings are worn, engine power should not come back... this can be caused by a dodgy CAS though. Check your CAS splines (you will need a timing gun to set it again after that).

Also you could be everfueling because the temp sensor is gone. Have you done an ECU check ? Try it too.

Finally, if you can hear your turbo going and all ... check for a boost leak somewhere too, it could be a joiner or a silicone hose moving under pressure.

codyace · 12-13-2012, 04:42 PM

If the car runs great after new sparkplugs, then eventually looses performance I'd check into a vacuum leak (if you are on a stock ecu/setup) or to make sure all is well. Sounds like you're fouling plugs more than anything.

240sx_LokiS14 · 12-14-2012, 04:00 AM

Quote:

Originally Posted by Croustibat

Did you do your test with a fully charged battery and the throttle wide open ? If not, do it again like that (and pull fuel pump fuse and ignition power transistor first) .

If you want to confirm the problem comes from the rings, do the compression test again but pour a spoon of oil in each cylinder before testing. If that is enough to get high compression again, then your rings are fubared.

If the rings are worn, engine power should not come back... this can be caused by a dodgy CAS though. Check your CAS splines (you will need a timing gun to set it again after that).

Also you could be everfueling because the temp sensor is gone. Have you done an ECU check ? Try it too.

Finally, if you can hear your turbo going and all ... check for a boost leak somewhere too, it could be a joiner or a silicone hose moving under pressure.

Right now i have a little ass tractor battery that im using to start my car cuhzz i have no room under my hood until i reroute my battery to the trunk.
& the rest imma have to check it out

240sx_LokiS14 · 12-14-2012, 04:01 AM

Quote:

Originally Posted by codyace

If the car runs great after new sparkplugs, then eventually looses performance I'd check into a vacuum leak (if you are on a stock ecu/setup) or to make sure all is well. Sounds like you're fouling plugs more than anything.

yea it seems as when my spark plugs go bad thats when it acts up but when there brand new the car doesnt act up at all..

12-13-2012, 02:57 AM	#1
240sx_LokiS14 Join Date: Jan 2012 Location: Temecula, CA Age: 29 Posts: 28 Trader Rating: (0) Feedback Score: 0 reviews	Low Compression all 4 Cylinders So i took my car to a friends shop to have them compression test it. reason was that at times when i drive it. It will bog under load and the rpm pick's up really slow i can hear the turbo spool and everything but the car just doesnt wanna go but then after a little while all the power will come back. This is while im driving this happens once in awhile but i would check my spark plugs n they would be black AF and i would switch them out and it would run fine..but i notice everytime i switch my spark plugs it doesnt act up until later on down the road..n theirs no type of smoke comming out my tail pipe. any ideas? My reading's were. 1st:110 2nd:110 3rd:110 4th:90 Last edited by 240sx_LokiS14; 12-13-2012 at 03:29 AM..

12-13-2012, 04:42 PM	#8
codyace Post Whore! Join Date: Dec 2004 Location: Poconos, PA Age: 36 Posts: 8,030 Trader Rating: (58) Feedback Score: 58 reviews	If the car runs great after new sparkplugs, then eventually looses performance I'd check into a vacuum leak (if you are on a stock ecu/setup) or to make sure all is well. Sounds like you're fouling plugs more than anything. __________________ *Want Air Conditioning in your SR20 Swapped car? Check out www.sr20acbrackets.com for more information! Quest Alternator Conversions for SR20!* Check my Group Buy! Tired of lousy internal gates? Go external wastegate with one of my manifolds, Check out my group buy

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12-13-2012, 03:11 AM	#2
waxball88 Zilvia FREAK! Join Date: Jun 2009 Location: Gainesville Posts: 1,061 Trader Rating: (9) Feedback Score: 9 reviews	Well for starters it seems like you need a rebuild. Thats VERY low compression far out of factory spec. If your car has black plugs, and bogging, i'd bet your tune is very rich. Do you have a wideband in car? Running rich for extended periods of time will lead to the cylinders being washed causing ring wear, which seems to be what the deal is for you.

12-13-2012, 03:20 AM	#4
waxball88 Zilvia FREAK! Join Date: Jun 2009 Location: Gainesville Posts: 1,061 Trader Rating: (9) Feedback Score: 9 reviews	Nope. Grab the mad scientist so you can rip apart the block to replace those piston rings you fried.

12-13-2012, 04:31 AM	#7
Croustibat Nissanaholic! Join Date: Aug 2011 Location: France - Toulouse Age: 41 Posts: 1,851 Trader Rating: (0) Feedback Score: 0 reviews	Did you do your test with a fully charged battery and the throttle wide open ? If not, do it again like that (and pull fuel pump fuse and ignition power transistor first) . If you want to confirm the problem comes from the rings, do the compression test again but pour a spoon of oil in each cylinder before testing. If that is enough to get high compression again, then your rings are fubared. If the rings are worn, engine power should not come back... this can be caused by a dodgy CAS though. Check your CAS splines (you will need a timing gun to set it again after that). Also you could be everfueling because the temp sensor is gone. Have you done an ECU check ? Try it too. Finally, if you can hear your turbo going and all ... check for a boost leak somewhere too, it could be a joiner or a silicone hose moving under pressure.