RPM's dip while turning steering wheel?

[dwd1985]

So seeing as how I cant get the power steering return hose for a few days from now (have to have it shipped, local dealership didnt have one in stock) I needed to add some fluid to the power steering. The car was on and in park and fully warmed up. So to make sure that the whole system got enough fluid, I added some, and got in and turned the steering wheel back and forth to fully lubricate the system. While I was doing that, I noticed that as I turned the wheel, my RPM's decreased about 100-150 RPM's. Can anyone explain this to me? It is extremely odd to me to think that the power steering system would somehow be related to the RPM's.

[mbtoloczko]

Originally Posted by dwd1985

So seeing as how I cant get the power steering return hose for a few days from now (have to have it shipped, local dealership didnt have one in stock) I needed to add some fluid to the power steering. The car was on and in park and fully warmed up. So to make sure that the whole system got enough fluid, I added some, and got in and turned the steering wheel back and forth to fully lubricate the system. While I was doing that, I noticed that as I turned the wheel, my RPM's decreased about 100-150 RPM's. Can anyone explain this to me? It is extremely odd to me to think that the power steering system would somehow be related to the RPM's.

The power steering system is driven by the engine. When the steering wheel is turned, this puts a load on the PS system which in turn places a load on the engine. The rpms will drop briefly until the ECU compensates for the engine load.

[Earthworm]

I was going to respond with the same information until I see it's already there.

The ECU will try to maintain a specific idle and when you turn the wheel it will cause the idle to drop. You can actually get the idle above normal once the ECU responds.

[dwd1985]

that weird that its something that I didnt notice until now. thanks for the info.