Power steering surge

Hello Andre, i have a VG30ET. I'm trying to figure out why I am getting a steering pulse on long sweeper turns at higher RPMs (around 3000+ RPMs. It feels like the power steering is (mildly) disengaging the re-engaging. Definitely, not reassuring when try to hold a line on a track or an on ramp. I also experience some power steering loss when drifting, again at higher RPM's. That said, it operates correctly on straights at high RPM's or turns at sub 3000 RPM's. Any thoughts or solutions?

Perhaps your power steering pump is cavitating from the high-load / high RPM combination. What happens if the have the car in Neutral at 3500 RPM, and turn the wheel -- do you feel the same issue when turning the wheel?

Thank you for your reply. I will give it a try and report.

I'd also be interested to know what you're assist control axis' are or if its a set amount of assist?

Recreating pulse in neutral - Unfortunately, I was unsuccessful and recreating the slight pulsation feeling at various RPM's above 3500.

Power assist control - The engine is a 1988 Nissan VG30ET, so the power control assist is surely just mechanical. From this, I would speculate that it is a set amount of assist. It may be that the PS pump needs to be replaced.

Try increasing the fluid level a little, it may just be exposing the pickup.

However, I would suspect the problem is slight belt slippage - can you increase the tension a little, or is it spring loaded?

Something else to consider is if there is a mild undulation through the corner, or variations in track surface, as they will affect the lateral grip and hence loading felt through the steering wheel? There may even be some deflection due to flexing bushings, or other components?

Hello Gord,

I have played with fluid levels without success. Track conditions could be a factor but on / off ramps seams less likely since the road surfaces would be different from one to another with the result being the same. All front end bushings are new but I will investigate serpentine belt slippage but I am most likely to replace the PS pump at this point. Thank you.