Quote:
Originally Posted by Ardent
Is the VSS input basically used to proportionately control (inversely) the motor's speed and/or turn on sensitivity?
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I am not at all sure. From reading the Toyota MR2 service manual, I gather that the pump itself is basically shut off at speeds above 12 MPH. The Durango certainly does not need power assisted steering above 12 MPH, as my wife proved last week when the power steering pressure hose failed on her.
Quote:
Originally Posted by Ardent
How does it operate when stopped? Is the motor fully off until demand is sensed?
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There is about a 1 second delay from when the unit first receives switched ignition power, then it closes its power relay. The unit appears to then command the pump go to full speed for about another 2 seconds, then it slows the pump down to some intermediate speed. After about another 5 seconds, the pump slows down to some lower minimum speed, and remains there until the steering wheel is moved.
Once that happens, I guess that the pump itself slows down as pressure builds up due to the steering wheel being moved. At this point, the unit speeds the pump up to provide the increased pump power necessary to move the rack to comply with the steering wheel movement. After the unit senses no more pressure is required, it will slow the pump down as before.
This relys solely on sensing pump speed as a demand indicator, and does not require a steering wheel rate sensor.
Quote:
Originally Posted by Ardent
Can any lag be felt between demand and response?
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Yah, I sense a little bit of lag when the Durango is stopped, but it's not really enough to be an issue. I figure that I can live with this tradeoff, if I can get better fuel economy.
Right now, though, I do feel the steering become choppy when I am maneuvering in a parking lot, and it can be somewhat unnerving if you're not expecting that to happen. I think that's due to the fact that the unit thinks the Durango is going 12 MPH when it's really going 6 MPH.