Jump to content
SAU Community

Recommended Posts

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)

IMG_bov.jpg

Tomas.

Link to comment
https://www.sau.com.au/forums/topic/295790-shuddering-boost-issues/
Share on other sites

  • Replies 67
  • Created
  • Last Reply

Top Posters In This Topic

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 by 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

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)

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.

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 :D

harts.

Edited by 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 :down: 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 :D:) )

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) :D

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 by 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).

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

gapped to 1.1 runs better :P

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 :P NGK BCPR6ES gapped to 0.8mm!

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

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)

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! :D

Edited by 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 :)

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.

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.

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

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

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

aparantly its most likely my 02 sensor playing up :D ( 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 by scotty nm35

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now



  • Similar Content

  • Latest Posts

    • Essentially, yes. Although I wouldn't put the AFM on the crossover pipe. I'd want to put it into what amounts to the correct size tube, which is more easily done in the intercooler pipework. I bought a mount tube for card stile AFM that replaces the stock AFM - although being a cheap AliExpress knockoff, it had not flange and I had to make and weld my own. But it is the same length and diameter as the stock RB AFM, goes on my airbox, etc etc. I don't have a sick enough rig to warrant anything different, and the swap will take 5 minutes (when I finally get around to it and the injectors & the dyno tune).
    • So to summarise, the best thing to do is to move recirc to between turbo and IC, and maf on the crossover pipe. Meaning I'd need a recirc flange, drill a hole in the piping on turbo outlet area. And drill hole on crossover to fit/weld maf sensor? Either that or put the MAF on the turbo inlet right?  Is an aftermarket recirc/blowoff valve recommended? Do currently have family in Japan so could probably bring something back with maybe a cheeky lil SuperAutobacs run?
    • Yep, so far most have said that it looks like corrosion on the wall from piston not moving. Which then has probably damaged the oil rings and caused those vertical marks. The longest the engine was still after the rebuild, was the winter of 2018 - 2019, plus the boat trip to Japan. When I shipped the car, it had normal gas in the tank but before that winter pause, it had E85 in tank.  In any case, even if either one of those was the cause, it happened close to 6 years ago and the car has been driven something like 30 000kms after the fact. Again, apart from the plugs and the dip stick, there is nothing in the way the car runs that would indicate what has been going on in the engine. I am going to consult a shop and ask their opinion, what would be the best approach. I do have some access to a garage I could use to diagnose further myself, but time is very restrictive. Might end up buying another engine that could be used while this one is being remedied. Without pulling the head, it will be impossible to find out if it needs another bore, but here's to hoping a hone would suffice.  Goddamnit, I would really have preferred this not happening.  
    • Boot is going to be replaced eventually. I just wire brushed what I could and rust converted. Then painted in rust kill primer. the spoiler also got repainted and plugs replaced on the ends. The under side of the bonnet is going to be black also, currently white. But red on the top side, same colour code as the silo to begin.
    • Hi guys, has anyone either purchased or built themselves a rotisserie for their car before? I can only just justify the need for one hence why I should just make one but at the same time, if I make one I can kiss another 4 weeks of potentially productive car working time goodbye because I'm building a bloody rotisserie....  I mainly want it for the application of the body deadener.  Cleaning the old stuff off, priming and then colour over the deadener doesn't worry me, it's just the application using the Schutz Gun that I feel would achieve a significantly better finish painting it side on and keeping the Schutz Gun upright.  I don't think they would work well on the side let alone almost upside down for some areas.  If the product I use (Terosun, etc) could work through a HVLP ok then it might be ok to apply without the rotisserie.   I can get one of these style ones for about $1200 which is pretty good value-     I reckon if I made one it would cost around $500 but it's more the time that it would take is more of a killer than the cost.  They look to hold their value pretty well second hand so I could always sell it after using it and realistically only lose $200-$300 at worst.  Or keep it and buy another project when this one finally sees the light of day... Anyone selling one...? Cheers!  
×
×
  • Create New...