Jump to content
SAU Community

M35 Help - Shudder @ 2500rpm

Blek

By Blek,
in Four Door Family & Wagoneers

 Share

Recommended Posts

Blek Collaborator

Blek

Posted
Posted

Evening all,

Was driving home on the F3 (M1, whatever!) tonight and the just noticed the car 'shuddering' at around 2500rpm. Not a heaps violent shudder or anything like that, but definitely noticeable. I managed to creep my way up to 110kmph, no worries, but anytime I gave it a bit more gas and it would drop to fourth revs go up etc I would get the shudder again. I nursed it back onto Pennant Hills Road, and did a bit of testing and confirmed, definitely shudders at around 2500rpm, irrespective of higher speeds etc.

I know this is about when the turbo starts boosting, but driving the car under 2500rpm seems fine. Can hear the turbo whining per usual. No errors on the dashboard or anything, idles fine, engine doesn't stall. Thinking possible leak somewhere/vacuum lines.

Wondering if anyone else has experienced something similar to this before? Trying to narrow it down.. bit dark out there to go check lol

Car is a 2001 AR-X, stock except zorst., 123,xxx kms.

Cheers

Link to comment
https://www.sau.com.au/forums/topic/465267-m35-help-shudder-2500rpm/
Share on other sites
C34stagRB Newbie

C34stagRB

Posted
Posted

I have a c34 stagea..i have a similar problem when at high revs..it has a shutter loses bit of power..and has a small like shutter when it idles...i think mine is fuel pump..because if i keep tank full or above half doesnt do it once...if i gets down near like quarter tank..it starts happening again...

Daleo Grand Master

Daleo

Posted
Posted

Evening all,

Was driving home on the F3 (M1, whatever!) tonight and the just noticed the car 'shuddering' at around 2500rpm. Not a heaps violent shudder or anything like that, but definitely noticeable. I managed to creep my way up to 110kmph, no worries, but anytime I gave it a bit more gas and it would drop to fourth revs go up etc I would get the shudder again. I nursed it back onto Pennant Hills Road, and did a bit of testing and confirmed, definitely shudders at around 2500rpm, irrespective of higher speeds etc.

I know this is about when the turbo starts boosting, but driving the car under 2500rpm seems fine. Can hear the turbo whining per usual. No errors on the dashboard or anything, idles fine, engine doesn't stall. Thinking possible leak somewhere/vacuum lines.

Wondering if anyone else has experienced something similar to this before? Trying to narrow it down.. bit dark out there to go check lol

Car is a 2001 AR-X, stock except zorst., 123,xxx kms.

Cheers

Hi mate, it sounds like your AFM has failed.

Do you have a light on the dash?

Blek Collaborator

Blek

Posted
  • Author
Posted

G'day Dale.

Thanks for your response. I've read about the troubles with afm's, but symptoms sounded a bit different to mine? ie no errors in the dash and car isn't stalling..? Still, afm is a good thing to have spares of, where are ppl getting theirs these days? Wrx sti compatible or is the verdict out on the cheap Chinese versions?

Btw, I took the car for a short drive yesterday. Seems the shudder/hesitation kicks in around 3000rpm now.. So much more drivable lol :P

Daleo Grand Master

Daleo

Posted
Posted

They don't always fail with the characteristic mil light and no idle, I've had one that would only fail when the intake temp went over 37 degrees, and it would only make the car stall at idle. Everything else was fine.

The current issue doesn't seem like the typical AFM symptoms; but checking all coil plugs and AFM plug is seated properly would be a good start, and making sure all the small vac hoses are connected in the plenum and valley area.

Maybe check all cooler piping for loose clamps and possible split joiners.

Blek Collaborator

Blek

Posted
  • Author
Posted

They don't always fail with the characteristic mil light and no idle, I've had one that would only fail when the intake temp went over 37 degrees, and it would only make the car stall at idle. Everything else was fine.

The current issue doesn't seem like the typical AFM symptoms; but checking all coil plugs and AFM plug is seated properly would be a good start, and making sure all the small vac hoses are connected in the plenum and valley area.

Maybe check all cooler piping for loose clamps and possible split joiners.

Cheers Dale. Hopefully I will get some time to check it out over the weekend.

Is it blowing smoke at all? Mine had similar symptoms to what you're describing plus the smoke blowing.

mmmmm Not really.. just a normal amount of white vapour-like smoke which disperses quickly, not something I would worry about. What was the issue with yours in the end, Duncan?

Dunc Mentor

Dunc

Posted
Posted

mmmmm Not really.. just a normal amount of white vapour-like smoke which disperses quickly, not something I would worry about. What was the issue with yours in the end, Duncan?

Split in the silicone hose on the cold side of the FMIC, took ages to find.I think I replaced every other silicone hose before I got to that one, as well as coil packs, spark plugs, hose clamps etc. Heres what it was running like:

  • Like 1
West Grand Master

West

Posted
Posted

Split in the silicone hose on the cold side of the FMIC, took ages to find.I think I replaced every other silicone hose before I got to that one, as well as coil packs, spark plugs, hose clamps etc. Heres what it was running like:

So is it fixed or it's still missing? Sounds awesome, like anti-lag :)

Ben C34 Grand Master

Ben C34

Posted
Posted

Split in the silicone hose on the cold side of the FMIC, took ages to find.I think I replaced every other silicone hose before I got to that one, as well as coil packs, spark plugs, hose clamps etc. Heres what it was running like:

https://www.youtube.com/watch?v=0QotAsFh7mc

A pressure test would have found the leak instantly.

Dunc Mentor

Dunc

Posted
Posted

A pressure test would have found the leak instantly.

Yes, if I'd had a kit or anyone I know had a kit I'd have used it.

So is it fixed or it's still missing? Sounds awesome, like anti-lag :)

Fixed ages ago, it was a pig to drive getting on to boost as it basically leaking air and over fuelling (as you can tell) at about 3-3.5k

  • Like 1
  • 2 weeks later...

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
 Share
Go to topic listing


  • Similar Content

  • Latest Posts

    • GTSBoy
      Leak from Tokico BM50 Brake Master Cylinder

      By GTSBoy · Posted

      HFM BM57 has a "bad" knee point, IIRC. It's not the same thing as the later R chassis MC.
    • Duncan
      Who has a Infiniti Q60, Q50 (V37)?

      By Duncan · Posted

      The ATTESSA is functionally identical to R34; there were a bunch of JDM models that continued ATTESSA including Fuga/Q70, Skyline/Q50, Cima etc as an option. All with Auto only and I think mostly for snow regions. AFAIK there were no AWD VR30DDTT sold in Australia - it is on my to do list to check regs for racing a LHD car in Targa/ATR/AASA/CAMS events because if I can get the auto to work it would be interesting to run a 4wd car The Ecuteck TCM tuning is the same model as their ECU tuning, they already have it for R35 and Dose's favourite, BMW. You buy "points" to allow your computer to be tuned, buy either a bluetooth (phone app) or bluetooth+USB+Key (phone and PC) dongle, and pay for a tune that will be locked to your tuner ( ). You can also access the tuning software yourself but 1. it is mega expensive and 2. these computers have a billion parameters that intersect, so how could you ever spend enough time on it to get a decent result.
    • MBS206
      Who has a Infiniti Q60, Q50 (V37)?

      By MBS206 · Posted

      Or, is it a case of what it is like owning an R series Skyline? NFI what the previous owner has done or fiddled with... Ha ha ha After reading through this thread, I went on a bit of a research about the Q50/Q60. Now I'm quite intrigued by them! Is the AWD in them more like a WRX where it's always AWD, or is it more like the ATTESSA in the GTRs? By the sound of this TCU tuning, this sounds like a case of someone has made some real software for it, and you just need the right piece of hardware, and then you license that specific vehicle/TCU. Or is this a case of the software will be really expensive so only a few tuners have it, and you still have to pay a license per vehicle?
    • CF.Panda
      R34 25GT Engine Light 21

      By CF.Panda · Posted

      By popular demand.. it was a coil. Got my hands on 1 new OEM coil, replaced with the one that made the less noise difference when I unplugged it while the car was running and started the car up. No stutter and the engine light was gone. I guess I’ll buy the other 5 they have lol
    • joshuaho96
      R34 25GT Engine Light 21

      By joshuaho96 · Posted

      No, code 21 is very straightforward. It can only be the things described in that diagnostic flow. In fact it has no way of knowing that the spark plug resistance is out of spec.
×
×
  • Create New...