Noisy Attessa

[Punk72]

Gday all

When pulling up to a set of lights i have a noise that sounds like a pump of some kind, Its not to loud but i am guessing that its not supposed to be there.

You can only hear the noise when pulling up and about half a second after coming to a complete stop the noise will stop, But if you slow right down

to less then walking speed it will still be there no matter how far you roll, The noise doesn't change speed or volume and it doesn't change if its in neutral or clutch in, Could it just be a noisy Attessa pump?

any ideas would be good

I had this posted in drive train and transmission and got no answers,

[_Ryan_]

whilst idling, check the fluid in the rear right of the boot.

[msports180]

As far as i understand the attessa pump isnt running all the time? Only when it needs to be? If it is running though will only be at a small output?

Normally if you get into the car, turn the car "on" but not start it you can hear the pump start, build pressure then stop.

I maybe wrong but thats my impression?

If thats the case then it shouldnt be what your hearing?

[Punk72]

I have checked the rear reservoir and when idling its a little over min

The noisy isn't there when idling or when first taking off just when coming to a stop and rolling to a stop, very strange sounds like a cheap fuel

pump

I assumed it was the attessa pump because i am sure its working all the time (well guessig) i don't know to much about the whole attessa system

its very strange and starting to get annoying not louder just annoying!!!

[iamhe77]

As far as i understand the attessa pump isnt running all the time? Only when it needs to be? If it is running though will only be at a small output?

Normally if you get into the car, turn the car "on" but not start it you can hear the pump start, build pressure then stop.

I maybe wrong but thats my impression?

If thats the case then it shouldnt be what your hearing?

That was my impression too.

Start the car first thing in the morning and walk straight to the drivers side rear wheel, you will here the ATTESA pump building up pressure in the system.

Is that the same sound you described?

Edited May 7, 2009 by iamhe77

[zei20l]

mine clicks on and off, i only notice it when im in the garage.

[KiwiRS4T]

Try bleeding it - 2 bleed points one on end of gearbox extension nr hose and one on top of diff - and if the fluid looks crappy change it with a good quality atf. (BTW if it comes to it i have all the atessa stuff spare - atessa ecu and the stuff that sits on top of the diff).

[Punk72]

thanks for all your help, I know nothing about the attessa system i dont even know where the attessa ecu is and didnt know where the pump

was until 2 seconds ago, , I might try and have a look tomorrow

cheers

Edited May 8, 2009 by Punk72

[mattye]

Actual sounds like the fuel pump....when u turn ur car to "on" the sound is the fuel pump primming.

Fuel pump would be 10 or so years old so its due for a new one anyway.

[mattye]

For your reading Theres a number of different system types but this is the one the Stagea uses.

ATTESA-ETS

The Electronic Torque Split version off this all-wheel drive architecture was developed for usage in Nissan's north-south layout vehicles, and was first used in August 1989 in the R32 Nissan Skyline GT-R and Nissan Skyline GTS4. It utilizes what is mostly a conventional RWD gearbox. Although the Skyline GT-R is exclusively AWD, ATTESA-ETS is also used in Nissan models that are also available as RWD such as the A31 Nissan Cefiro which was the second Nissan to feature the system exactly a year later in August 1990. Drive to the rear wheels is constant via a tailshaft and rear differential, however drive to the front wheels is more complex by utilizing a transfer case at the rear of the gearbox. The drive for the front wheels comes from a transfer case bolted on the end of an almost traditional RWD transmission although the (bell housing is slightly different to allow the driveshaft for the front wheels to pass it, the main body is exactly the same as the RWD transmission, the tail-shaft is different to couple to the transfer case). A short driveshaft for the front wheels exits the transfer case on the right side. Inside the transfer case a chain drives a multi-plate wet clutch pack, torque is apportioned using a clutch pack center differential, similar to the type employed in the Steyr-Daimler-Puch system in the Porsche 959. On the rear differential is a high pressure electric oil pump, this pump pressurises Normal ATF oil (0-288psi) into the transfercase to engage the clutchpack. The higher the oil pressure the transfer case is supplied with, the more the clutch pack engages, this is how the torque to the front wheels is varied. The transfer case has its own dedicated ATF (Nissan special ATF) oil to lubricate the chain/clutch pack. The front driveshaft runs along the right side of the transmission, into a differential located on the right of the engine's oilpan. The front right axle is shorter than the left, as the differential is closer to the right wheel. The front left axle runs through the engine's sump to the left wheel.

The ATTESA-ETS layout is more advanced than the ATTESA system, and uses a 16bit microprocessor that monitors the cars movements at 100 times per second to sense traction loss by measuring the speed of each wheel via the ABS sensors. A three axis G-Sensor mounted underneath the center console feed lateral and longitudinal inputs into an ECU, which controls both the ATTESA-ETS 4WD system and the ABS system. The ECU can then direct up to and including 50% of the power to the front wheels. When slip is detected on one of the rear wheels (rear wheels turn 5% or more than the front wheels), the system directs torque to the front wheels which run a viscous LSD. Rather than locking the AWD in all the time or having a system that is "all or nothing", the ATTESA-ETS system can apportion different ratios of torque to the front wheels as it sees fit. This provides the driver with an AWD vehicle that performs like a rear wheel drive vehicle in perfect conditions and can recover control when conditions aren't as perfect. The advantage to a more traditional ATTESA (Viscous LSD) system is response in hundredths of a second.

ATTESA E-TS system is used in the following models:

· R32 and R33 (1989-1997) GTS4 Skyline

· GT-R - 1989–2003

· Nissan Stagea

· A31 Cefiro

· Infiniti G35x/Nissan Skyline (V35 & V36)

· Infiniti FX

· Infiniti EX35 (with Active Brake Limited Split for side-to-side torque split, as needed)

· Nissan Fuga (Known as Infiniti M in export markets)

· Nissan GTI-R

[scooter_r33]

hey did you ever figure out what this sound was? i have it too..

[pvdm]

I know this is an old post but I have exactly the same problem and just wondering if anyone knows what this annoying pump sound might be? It is exactly as the OP described.

I have just bled the attessa system and it did not stop the noise. As soon as i started bleeding it i knew it was not the same pump sound.

I dont think it is the fuel pump because it seems to be linked to wheel speed. If you are rolling slowly it will keep running until i come to a complete stop. Then it will stop completely until i start moving again. Car is a stagea C34 RS4S factory manual. Hope someone can help!

[Dogzilla]

The pump near the rear of the diff has gears inside that are stripped which are making that noise. I'm going through the same thing at the moment.