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Running Rough Rb25/30

8znR33

By 8znR33,
in Engines & Forced Induction

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8znR33 Proficient

8znR33

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Posted (edited)

OK hopefully this is the right section for this:

my 25/30 recently has been running rough on n off but now its staying like it even more, my mate says it sounds like i dropped a cylinder but it still drives normally except for it sounding kinda like a V8 (best wat to describe it i think) but i did a compression test and its pretty even through out all cylinders.

I hav shecked the spark plugs and changed them, tested the splitfires they are fine, checked the plugs for the injectors (injectors were cleaned and tested b4 they went in), it has a bit of smoke now form the exhaust doesnt really smell like fuel just normal exhaust fumes when in a carpark is just more noticable. i have found theres some oil seaping from the head gasket but not heaps, i have checked the vacume lines and think i will change all the lines this afternoon to see if that helps.

i have also earthed the head to the chassis of the car and the block is earthed and these are not loose as i have already check them.

the head is a stock rb25 with vct, and the bottom end has forged pistons stock crank n rods, if you need more info on the specs to help please let me know.

any help would be appericated

Thanks

Lok

Edited by 8znR33
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SargeRX8 Grand Master

SargeRX8

Posted
Posted

Hmm, my mates camry had a leaky headgasket. Be aware noise can escape the headgasket. You will lose.... well alot of everything, oil, pressure, power etc. Wipe away the oil and take it for a normal drive. If there is oil coming out then you need to change the gasket. If there is no oil, take it for a hard drive and then check again. Driving hard increases oil pressure and that will cause it to seep from a leaking gasket.

Just to double check, you don't have any intake or vac leaks? All intercooler piping connected nice n tightly? Just double check. Also check if you've got any cracks in your headers.

8znR33 Proficient

8znR33

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  • Author
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Hmm, my mates camry had a leaky headgasket. Be aware noise can escape the headgasket. You will lose.... well alot of everything, oil, pressure, power etc. Wipe away the oil and take it for a normal drive. If there is oil coming out then you need to change the gasket. If there is no oil, take it for a hard drive and then check again. Driving hard increases oil pressure and that will cause it to seep from a leaking gasket.

Just to double check, you don't have any intake or vac leaks? All intercooler piping connected nice n tightly? Just double check. Also check if you've got any cracks in your headers.

its got good pretty high oil pressure reading on the stock gauge in the cluster, i wsa told its normal for the high oil pressure, and with the seaping its only leaking out the side of the block but its not mixing with the coolent etc, i cant really hear much of the noise in the engine bay but mainly through the exhaust, i will double check all the piping and swap out all the vacume lines this arvo.

if i had to get a new head gasket would i need to get the head n block re-decked? its only run for 950kms cause its a run in tune. havent been boosting it just been taking it easy cause the tuner told me i shouldnt boost it for the first 1000kms.

my intake is a modified stock to be forward facing and the exh manifold is steam pipe and im pretty sure they arnt cracked. im pretty sure all piping is nice and secure but i will check again

8znR33 Proficient

8znR33

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heres a video of how it sounds.

if the video didnt work heres a link: http://www.youtube.com/watch?v=MEQpQBIOjh0

<object width="425" height="344"><param name="movie" value="http://www.youtube.com/watch?v=MEQpQBIOjh0&hl=en&fs=1"></param><param'>http://www.youtube.com/watch?v=MEQpQBIOjh0&hl=en&fs=1"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/watch?v=MEQpQBIOjh0&hl=en&fs=1" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"></embed></object>

8znR33 Proficient

8znR33

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if the idle is rough also then disconnect 1 coilpack at a time and see which one DOESNT change the engine idle,

this will help diagnose which cylinder it is.

how rich was the run in tune?

new injectors or ???

i've checked all the coil packs they are firing and the compression in all cyls are pretty much the same new sparkplugs, its a run in tune ( but was running fine b4, at first it was just on n off and went back to normal but now its staying like that, the injectors are second hand but i had them cleaned n flow tested.

8znR33 Proficient

8znR33

Posted
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Posted (edited)
sounds like mine when it was running on 4 cyls. it idled and drove ok but sounded like a WRX.

yea it does sound like a wrx when driving, did you find out what was causing it to happen??

Edited by 8znR33
TiTAN Grand Master

TiTAN

Posted
Posted

in mine it was two fouled up spark plugs, replaced all 6 and it went fine again.

find out which cyl/s are missing and move on from there. with the car idling disconnect each coil pack one at a time if the idle gets worse its not that one, then repeat except disconnecting an injector instead.

8znR33 Proficient

8znR33

Posted
  • Author
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in mine it was two fouled up spark plugs, replaced all 6 and it went fine again.

find out which cyl/s are missing and move on from there. with the car idling disconnect each coil pack one at a time if the idle gets worse its not that one, then repeat except disconnecting an injector instead.

really? damn i've changed all my sparks already but i guess ill have to check again.

Cheers

8znR33 Proficient

8znR33

Posted
  • Author
Posted

soo cyl 6 isnt firing, im not sure what is up the splitfires are firing and new plugs are in and did the compression test, does anyone know why my car is being such a piece of crap??? lol. think might just have to take it to the shop.

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