ATTESA System
Hi All,
I have an issue with my ATTESA System on my BNR32. I've been hunting this issue for years, but with very little success, so am hoping to find someone with a knowledge of this system.
What's happening is that at motorway speeds (60mph+), only on part throttle (1/4 throttle) the car is lurching, vibrating and bucking. When I'm off throttle, it's very smooth, when I put my foot down it's smooth.
When I remove the fuse to make it RWD only, it's completely smooth.
I can see on the torque split in the instrument binnacle that the car is blipping torque to the front wheels, as the needle jumps. Presumably, this is what's creating the lurching.
The engine, prop shaft, rear diff and gearbox are very solid.
I've tried to learn about the system, but I've never really found anyone who's had a similar experience. Most of my driving is low speed around town, so it doesn't normally impact me.
So here's where I'm at...
I understand that the torque split gauge in the binnacle isn't telling me what's happening at the wheels, but is actually telling me what signal is being sent by the ATTESA ECU? If that's the case, and I'm understanding it correctly, root cause is unlikely to be a hardware issue.
In terms of sensor inputs to the ATTESA ECU, my understanding is that it sends power to the front wheels, based on G sensor, rear wheel ABS sensor and TPS readings. Please correct me if I'm wrong here, but these seem to be the inputs which may be most likely to cause this?
I can rule out G sensor, because the system operates ok at low speeds and full throttle. (Or maybe the lurching is still happening, but less noticeable at lower speed?).
I've replaced the TPS recently, and it's functioning ok, so I believe it's unlikely to be causing this problem.
That leaves me with ABS sensors on the rear wheels, next to the diff, or potentially an issue with the ECU itself.
As I say, this has been going on for years, and I've never managed to get to the bottom of it, so would really appreciate any help or guidance from anybody who knows the system well. Even if you can tell me if I'm completely barking up the wrong tree... I really don't want to start firing a parts cannon at it, but I'm concerned that the vibration and bucking will create problems with the hardware.
Thanks in advance.