Pulsing Gtr

[R.3.2.G.T.R]

My issue is been around for a while now.. Basically when in

gear every 5secs or so, can feel the car pulsing.. Not jerking

in a big way but very noticeable..

doesn't happen when I'm in neutral.. Same size tyre all around

balanced n no flat spots or bumps.. stock gearbox with single plate

nismo clutch.. Gearbox n diff fluids are good

any ideas or suggestions

[blind_elk]

It really sounds like ATTESSA problem. Swap the tyres F<->R, see if it goes away.

[Moodles2]

Watch the torque split gauge for activity, ATTESSA can feel like a rubber band effect when little bits of torque in quick spurts are sent to the front wheel when it thinks there is traction loss. Even try driving around with the 4WD fuse pulled to see if it still happens.

[MrStabby]

Checked tyre pressures recently?

Also, how's your alternator? Mines stuffed at the moment and ATTESSA gets emo on low volts...

[R.3.2.G.T.R]

Great suggestions guys.. will rotate tyres to see if it helps

have driven in 2wd but can still feel the pulsing

my torque gauge does play around sometimes sitting on half

way when I'm highway driving.. if I get off n on the gas it

returns to normal for a while

I should mention my speedo also bounces around +/- 10km

until 80km when it's normal n steady, thinking of getting new

speedo cable but may be related to the pulsing problem

didn't realize attesa is sensitive to battery voltage, my

wrxhoon battery seems to be on the way out, apexi turbo timer

shows ~10v sometimes when starting n always flashes unless

I have min 12.6v

Might have a go at bleeding the attesa system

[R.3.2.G.T.R]

Checked tyre pressures recently?

Also, how's your alternator? Mines stuffed at the moment and ATTESSA gets emo on low volts...

how were u able to determine that the alternator was faulty? Auto electrician?

I'll be getting a new battery as well

[Brandon]

I dont know if its any help but I've got ao similiar problem. No real issue with it but its a lil annoying. Just as you said, it happens after a gear shift and for my case, probably once for a journey (so I'm guess its not really dependent on gear shifting), meaning it only happen once or max twice (rarely) when I'm cruising. Its usually 4th gear or 5th gear (so I'll get it when I'm cruising on highway). Talked to Dan at ERD and he reckon might be the attessa pump but shouldnt be any problem but it might be a start sign of failure etc (not 100% certain on root of problem but just guessing). He told me to note the torque split gauge but dont know if it happens too quickly that I couldnt pick it up or its really not showing anything.

Just a quick description, it just feels like a sudden jerk and it goes away after that. The feeling is like erm... sudden lost of power (not total loss but something like when you're in first gear foot off accelerator and suddenly step on it again) but again its like a split sec feeling.

[Rowdyr32]

Some pfc's do it on cruise. Feels like a cough. Not pulsing though. It can suposidly be stopped by turning the o2 sensors off. Just a different avenue to maybe look at.

[Brandon]

Hmmm... it'll make a LITTLE bit of sense too. Because I got it only after I put the pfc on and this only occur only AFTER the tune (install/tune same day). Dont think it'll do any harm to the car yah? Yea maybe pulsing isnt the right word for it. Cough or I'll call it sudden jerk. It'll make more sense if the problem is pfc as I was told the torque split gauge will have a reading if its the attessa pump's problem.

[Brandon]

Alright. Sorry to hijack the topic but just thought I might confirm Rowdyr32's answer. I've called my tuner up and he's confirm its a very common thing for pfc and it doesnt cause any problem. And yes, it normally just does it once or max twice for my case and typically on cruise, 4th or 5th gear.

[MrStabby]

how were u able to determine that the alternator was faulty? Auto electrician?

Voltmeter in the dash - 10v or less, followed eventually by a stalled motor :-)