Rack and Pinion ? Hard to turn LEFT only?

[tobydale]

Hello,
I have a 97 Deville that is very difficult to steer when turning left only. It feels like there is no power steering at all in that direction. I had a salvage yard rack from a 96 in the shop so I swapped them out yesterday hoping it would solve my issue. After switching them out I flushed the system until it pumped clear fluid. Problem is exactly the same. Turning right is fine and it always returns to center normally after a left or a right turn. I have read that these racks are known to "go bad", but what are the odds of the one from the salvage yard having the exact same problem? When these racks go, do they always fail in the same manner (ie. hard to turn left only)? there is a small spot in the rotation turning left that it feels "normal" but just a very small spot. I have no problems buying a new rack but I want to get some feedback before I do so. I have no codes, the pump does not make any noise and increasing the RPMS does not help the problem. Is there anything else that can cause this left only problem? How does the electronic "magna steer" work?
I assume that is the electrical plug down by where the lines go into the rack. If it is malfunctioning I should still have "normal" power steering correct? The car drives down the road perfect with no pulling or memory steer. Any help is appreciated.

[Tony Silva]

That plug you are referring to is for the speed sensitive power assist system.....Could be faulty computer if you used the junk yard sensor (which I assume came with the used rack). The magna steer works like this::: full power assist at low MILES PER HOUR. Ok, as you increase vehicle speed the magna steer system DECREASES the line pressure making it more difficult to turn the car. (This is good for freeway driving). At lower speeds the pressure is high, making it easy to turn the steering wheel. The computer reads left (turning) input, right (turning) input and centered (no turning) input. That's about all I know 'bout this. My best and only guess would be that the computer is reading left input at low speed.