Shuddering (boost Issues?)

[atomaly]

i've recently started feeling some shuddering, or jerking i.e "juddering" and the engine feels like its cutting in and out kindof..

started at 100->110kph, then once the car is quite warm it happens at lower speeds aswell!

i was thinking to check all my pipes and the seal (looks a bit old) below where the BOV is (cos it vents to atmos)

any other ideas??

anyone else had this issue beforE?

(picccccccc)

Tomas.

[FR33K]

You should probably block that pipe off...

[atomaly]

You should probably block that pipe off...

oh so a seal like that doesnt cut it? (it actually looks like a rubber doorstop (possibly IS) )

Edited November 11, 2009 by atomaly

[KiwiRS4T]

Try replacing the stock (plumbed back) bov to se if that eliminates the problem. have you replaced your plugs lately? (With say NGK BCPR6ES gapped to 0.8mm).

[kidafa]

what kinda load? at WOT?

Ive us a bit more of an explanation on when its doing it mate

[atomaly]

Try replacing the stock (plumbed back) bov to se if that eliminates the problem. have you replaced your plugs lately? (With say NGK BCPR6ES gapped to 0.8mm).

i have a problem there. i bought it as is! so no going back to the stock!.. it has only started doing it last few times i've driven it..

and when i got the my front breaks done, i was informed the "door stop" seal looked like it needed replacing!

i havent replaced the plugs as of yet since i bought it about 6 months ago!

maybe a good time to? i'm planning on doing it myself (i havent done it before)

anything i need to be mindful of? i'm a bit of a n00b haha.

and wheres the best place to get the NGK plugs from?

i found this..

Spark Plug Guide for RB25DET

[atomaly]

what kinda load? at WOT?

Ive us a bit more of an explanation on when its doing it mate

when its warm it happens pretty much on medium to heavy boost, but normally starts at around the range of 2500 RPM.

i do remember its always had a bit of dip at that mark, but was never juddery and noticable til now!

when its cold, its not really noticeable (hence when i got my breaks done they couldnt notice it when they went for a drive)

[KiwiRS4T]

i have a problem there. i bought it as is! so no going back to the stock!.. it has only started doing it last few times i've driven it..

and when i got the my front breaks done, i was informed the "door stop" seal looked like it needed replacing!

i havent replaced the plugs as of yet since i bought it about 6 months ago!

maybe a good time to? i'm planning on doing it myself (i havent done it before)

anything i need to be mindful of? i'm a bit of a n00b haha.

and wheres the best place to get the NGK plugs from?

i found this..

Spark Plug Guide for RB25DET

Yep that guide is from the "how to " section in the skyline part of this forum. Ther's another guide there as well. While you've got them out carefully examine the coils for evidence of arcing.

[stageaharts]

Hmmm, maybe a very specific detailed description would garner some more knowledge from people in the the know. I'll put my two cents in though The judder you describe sounds very much like the airflow issue that my car experienced when I put my front mount on. Have you added any new mods to the car recently? Too much airflow causes the ECU to cut fuel until the airflow level is at an 'acceptable' level again, it will do this repeatedly as long as the problem is present which causes a 'misfiring', 'jerking' and 'juddering' sensation. I wonder if the seal has perished then it may be altering the air flow characteristics of the system? I would buy what's necessary to plug that hole tight, get the spark plugs and install and test separately, if you do both at the same time then you won't know what the problem was

harts.

Edited November 11, 2009 by stageaharts

[atomaly]

Hmmm, maybe a very specific detailed description would garner some more knowledge from people in the the know. I'll put my two cents in though The judder you describe sounds very much like the airflow issue that my car experienced when I put my front mount on. Have you added any new mods to the car recently? Too much airflow causes the ECU to cut fuel until the airflow level is at an 'acceptable' level again, it will do this repeatedly as long as the problem is present which causes a 'misfiring', 'jerking' and 'juddering' sensation. I wonder if the seal has perished then it may be altering the air flow characteristics of the system? I would buy what's necessary to plug that hole tight, get the spark plugs and install and test separately, if you do both at the same time then you won't know what the problem was

harts.

thanks! i'll change that rubber seal to start with! maybe replace it with something better? what would be the best way to plug the hole tight? / what to use? (sorry i've never done this before )

i've only noticed the juddering 'since' i got the car serviced and the oils were changed,

and also the gearbox was serviced (which fixed my 4th gear synch issue)

the juddering only happens after the car is warmed up quite a bit. (say 30 mins of driving)

he did mention about the seal being perished when i got the service though!. i had a bit of a fiddle with it last night, and it seems quite stuck-perished onto the pipe! (and i didnt wanna force it off and break it b4 having something to put back on it) haha

Edited November 11, 2009 by atomaly

[_Ryan_]

Try replacing the stock (plumbed back) bov to se if that eliminates the problem. have you replaced your plugs lately? (With say NGK BCPR6ES gapped to 0.8mm).

gapped to 1.1 runs better

i am going to try this "theory" of needing small gap with high boost on the 32 when i up the boost... going to try low-mid 20's psi with 1.1 gap...

stagea stock boost 1.1 is fine, r32 14psi 1.1 or .8gap is fine. if it isnt i would be trying silicon on coilpacks as others have

[atomaly]

gapped to 1.1 runs better

i am going to try this "theory" of needing small gap with high boost on the 32 when i up the boost... going to try low-mid 20's psi with 1.1 gap...

stagea stock boost 1.1 is fine, r32 14psi 1.1 or .8gap is fine. if it isnt i would be trying silicon on coilpacks as others have

just spoke with my mech and he said the same thing NGK BCPR6ES gapped to 0.8mm!

i'll check the coils for arcing while i've got them out!

[BensDR30]

From a 'spark' perspective, if your stock setup misfires at 1.1mm then you've either got knackered plugs, or coils or both.

Running a smaller gap makes is just making life easier for the spark, and on 'mild' engine is simply masking another issue.

(Your economy and power will also suffer when you start closing things up)

[atomaly]

in regards to the BOV return pipe seal being perished... what would be the best thing to use to seal it off this time, and where would i get it from ?

i'm a n00b i know!

Edited November 20, 2009 by atomaly

[atomaly]

in regards to the BOV return pipe seal being perished... what would be the best thing to use to seal it off this time, and where would i get it from ?

i'm a n00b i know!

anyone? i had a look in a few different auto stores but they have nothing even similar to what i need

[stageaharts]

Wouldn't know the definative answer mate, I would imagine it would have something to do with a bung and/or seal with zip ties. Ask your mechanic for a professional solution

[QWK32]

pull the steel pipe off and get a cap welded on. thats if you can afford to have the car off the road while you do it. or get a piece of silicone joiner or similar, put it on the return pipe and use a steel bung to block off the other end of the joiner. this way you can easily put a plumb back bov back on if you want to.

i think you'll struggle to find another bit like whats already on there, i know you get one in a HKS SSQV kit, maybe other manufacturers supply something similar, post up in the Wanted to Buy section and see if anyone has one lying around they aren't using.

[KiwiRS4T]

You could go to a wrecker and get the original hose or go to an engineering supply store and get a short length of hose the right diameter and then either get a steel plug from the same store or if they don't have one from a plumbers supply store or just cut off a piece of solid steel pipe (maybe from an engineering shop) and stick that in the hose and secure it with a clamp.

[atomaly]

okay so i posted in the general Forced Induction Section of SAU.

aparantly its most likely my 02 sensor playing up ( should be changed every 80,000km according to my sources ) . will go for a drive tonight with it unplugged and see how it goes

[scotty nm35]

okay so i posted in the general Forced Induction Section of SAU.

aparantly its most likely my 02 sensor playing up ( should be changed every 80,000km according to my sources ) . will go for a drive tonight with it unplugged and see how it goes

Changed? Bugger that.

Drop around mate and I will try cleaning the AFM for you. If not it could be the solder joints inside. Then start changing things.

Edited November 25, 2009 by scotty nm35