AMT Posted January 26, 2016 Posted January 26, 2016 (edited) Ok I'm used to it, I've had it... including today going home in the stop start traffic...yay *waves hands unenthusiastically*. What exactly causes the jerk? Everythings clean, been for its service and sparks not long ago and nothing is covering anything as far as I'm aware. Known fault but apparently not doing any damage... so what the hell is the engine up to when its bucking at low speed?? lol Just out of sheer curiousity. Mines seems to do it most when slowed right down and your kinda rolling in traffic and no matter whether 1st or 2nd or 3rd when you even gently touch the throttle at times it will 'buck' forward a bit and I'm nowhere near the clutch. And even though I'm not on the clutch I thought it sounded like the flywheel noise at times (but could be wrong), is it something about it hooking up when not on the throttle or is it the actual engine itself Edited January 26, 2016 by AMT Quote
Jez @ H-Dev Posted January 26, 2016 Posted January 26, 2016 We had a car with a similar problem. Turned out to be the ECUs control of the exhaust cam timing - it was overshooting the target by a large amount. Remapped the target exhaust cam timing and it was nice and smooth again 1 Quote
AMT Posted January 26, 2016 Author Posted January 26, 2016 (edited) Awww I thought this was just a 'common' thing haha So my cars got an issue? I won't be paying for a remap any time soonish so is it doing the car any harm or is it just annoying (I can deal with annoying if it means the cars fine haha) and thanks for the reply! Edited January 26, 2016 by AMT Quote
Jez @ H-Dev Posted January 26, 2016 Posted January 26, 2016 If this is the problem affecting your car then it's probably just annoying - shouldn't do any damage I wouldn't have thought 1 Quote
Jp606 Posted January 26, 2016 Posted January 26, 2016 Pretty common on the HRs, mine went away when I got it mapped. Quote
matt89 Posted January 26, 2016 Posted January 26, 2016 Mine has a buck when in slow traffic but not bad enough that I couldn't correct it with careful clutch control. At least my left leg is stronger than ever.... Remap may be the way though if you've already tried every combination of revs and clutch to rule out the simple things. Quote
Mark@Abbey m/s Posted January 27, 2016 Posted January 27, 2016 Yep as Jez said it is an exhaust cam control issue. Old dual mass flywheel doesn't help either we have found. One of those issues that once you notice it you keeping feeling the issue and it drives you made! Quote
rabbitstew Posted January 27, 2016 Posted January 27, 2016 Have to say i never noticed this with my HR! Quote
Jay Kay Posted January 27, 2016 Posted January 27, 2016 Mine does it too, bloody annoying it can be. I assume it was a fuelling/mapping issue, but others seem to be saying in the exhaust cam timing. I have heard that a re-map can make it a lot better Quote
HiddenWomble Posted January 27, 2016 Posted January 27, 2016 mine was quite a bit worse on pop chargers but still has the buck on stock air filters. looking forward to end of the year when i can get a remap Quote
AMT Posted January 27, 2016 Author Posted January 27, 2016 (edited) Thanks everybody! Just wanted to find a bit more detail on the actual cause. I've been with it since 2012 so probably the cars fine and never found any issues on services so... it is annoying but not... fork out loads of money remap annoying. haha Edited January 27, 2016 by AMT Quote
CJRamze Posted February 14, 2016 Posted February 14, 2016 Goddamit, I tried going new exhaust and hfc thinking it might fix it. I'm sure it made it worse Cats throw an eml so decats and a map! Sent from my SM-N910F using Tapatalk Quote
Jay Kay Posted February 14, 2016 Posted February 14, 2016 Think hfc made mine worse Sent from my HTC One using Tapatalk Quote
AMT Posted February 15, 2016 Author Posted February 15, 2016 What exactly does doing the HFC ...do? What benefit is there? (Im not mechanical lol) All I ever see is problems on this about doing it and failed MOTS ... why would you bother, just stick to normal and put an exhaust on it ..no? 1 Quote
Richf Posted February 15, 2016 Posted February 15, 2016 What exactly does doing the HFC ...do? What benefit is there? (Im not mechanical lol) All I ever see is problems on this about doing it and failed MOTS ... why would you bother, just stick to normal and put an exhaust on it ..no? 15 hp or so i guess thats why they are popular Quote
Roscoe Posted February 15, 2016 Posted February 15, 2016 What exactly does doing the HFC ...do? What benefit is there? (Im not mechanical lol) All I ever see is problems on this about doing it and failed MOTS ... why would you bother, just stick to normal and put an exhaust on it ..no? I just kept standard cats and put a cobra resonated on. Still got some extra bhp's with an uprev on standard cats, I didn't want the rasp that comes with hfc's. This is on a HR. 1 Quote
Jay Kay Posted February 15, 2016 Posted February 15, 2016 Hfc shouldn't fail an mot, it's decats that do that. Hfc, or high flow cats, are still cats, but less restrictive than the standard ones Sent from my HTC One using Tapatalk Quote
glrnet Posted February 15, 2016 Posted February 15, 2016 Hfc shouldn't fail an mot, it's decats that do that. Hfc, or high flow cats, are still cats, but less restrictive than the standard ones Sent from my HTC One using Tapatalk Shouldn't do but have been known to. Quote
350Z HR in NZ Posted April 21, 2017 Posted April 21, 2017 I had exactly the same problem when bought my 07 HR a few months ago. I couldnt live with it so took it back to the dealer. In my case they diagnosed the fuel dampers as the fault. There is a fuel damper on each fuel rail. We got some from the US on Ebay, I think they were about 25 USD each and dont take long to install. Mine runs really smooth at low speeds now. It's a lot more enjoyable to drive Dont accept the problem. Give the dampers a go Quote
ConnorW06 Posted April 21, 2017 Posted April 21, 2017 Has this exact same snag with my HR from the day I test drove it, got in contact with Mark at Abbey and got a Uprev remap and it completely rectified the issue! Quote
AMT Posted April 21, 2017 Author Posted April 21, 2017 Oh this threads jumped back lol. I kinda live with it, irrating as hell... watching a DB9 infront of me, going home from work today, with its paddles just smoothly moving along So if I took this to a mapping place and they hooked up some electronic wizardry would this be easily noticed that this ECU exhaust cam timing thing was out?? Quote
350Z HR in NZ Posted May 3, 2017 Posted May 3, 2017 Maybe not. Mine did not throw up an trouble code. They did a re-learn of the exhaust valve timing. They tried this several times but it kept going out of sync. They reckon the faulty fuel dampers caused this to happen. After the dampers were changed they did the re-learn and its been okay since. Quote
raptor07GT Posted October 17, 2018 Posted October 17, 2018 holy thread revival.............. yeah my 07HR does this cough on low rev throttle openings. i thought it was me learning to drive a new (to me car) but it's defo not my pedal control. Damned annoying! Might as well get the exhausts changed and then the remap. I thought n/a's were supposed to be silky smooth ? Quote
cs2000 Posted October 24, 2018 Posted October 24, 2018 FWIW, mine has been "jerky" since it has the UpRev map loaded onto it, ive heard the pops and bangs cause the jerkyness as a side effect Quote
TubbyZ Posted October 25, 2018 Posted October 25, 2018 My car has been remapped at TDI North and had multiple maps on it. I have noticed the pops and bangs map to be the "jerkyest". However once my car is warmed up I notice it doing it quite a bit. Quote
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