Studiogeek

iTrader: (6)

Hi,
Yesterday while I was installing my Goodridge SS lines, a buddy helping me out topped off my power steering. I remembered reading you could easily overfill it resulting in leaks, diminished feel etc. I made a mental note to check it but forgot. On the way home I was concerned with making sure the brakes were perfect, then after a few minutes, I noticed how "twitchy" and light the steering was. It felt light and numb like my Mafia style 80's Lincoln Continental felt.
I got out the car checked it and it was overfilled. I went into the trunk and pulled out my turkey baster that I keep in the trunk after overfilling it once before. I pulled some fluid out until it was just below the hot mark with the car off. I remember reading that keeping the cap off and car off, you turn the wheel lock to lock for as long as your arms last and that will get air out so I tried that. I also tried it after starting the car.
I noticed that somewhere in this process (last 2 days) my power steering had also gotten much quieter, maybe that started after the bleeding and leveling off.
I also noticed that the fluid looked less turbulent inside the reservoir. It was quieter and less turbulent but the FEEL was way off.

Did i break my steering or fix my steering?

Could it be that the heavier steering was the steering malfunctioning, and the light steering is the car working properly? I REALLY doubt it because it does not feel like a sports coupe to me anymore. It feels Cadillac, Lincoln assisted.

I HOPE this is NOT the car running properly because I like the heavier steering MUCH MORE!

You guys wouldn't describe the Sc400 steering as "light" or "twitchy" when properly functioning would you?

Something is not right....

EDIT: I just learned about our "Progressive Power Steering". I think this may be my issue. It perhaps is stuck ON.

NixusSC

iTrader: (2)

I would think lexus steering would be luxurious/ light, not heavy and under assisted.

Every power steering system i've ever repaired or serviced, you always bleed the system with the car running/cap off, steering wheel lock to lock to get the bubbles out .

SC4Paulo

iTrader: (2)

Yeah my LS was stupid light, traded it for the SC it was much heavier to my liking, turns out my PS was dry, topped it off, felt like my LS again -_- not really good when you drift, I don't know which way I'm turned lol

Studiogeek

iTrader: (6)

Yes, i did that as well. I read both so i tried both. It wasn't heavy before, it was perfect to me, solid and firm with lots of feedback from the front end in the way of mild resistance. It's one finger light like my Lincoln was. I thought there was something built in to assist heavily at slow speeds and less so at higher speeds. Thanks..
That definitely helps in my analysis quite a bit. Maybe that is just what happened to me. It was noisy in the winter sometimes and REALLY turbulent in the reservoir. It's totally silent and not so turbulent in there now. It's starting to look like I fixed it, not broke it. Oh well...... ;-)
Thanks

Studiogeek

iTrader: (6)

Apparently we have "Vehicle-speed-sensing, progressive power-assisted rack-and-pinion steering". Perhaps whatever is responsible for the "Vehicle-speed-sensing" is malfunctioning.

Studiogeek

iTrader: (6)

Check THIS link. Coincidentally, it lists changing to stainless steel (PS) lines as the cause of loosing Progressive Power Steering but does not elaborate at all.

Then references THIS interesting link about modifying the PPS for heavier steering feel.

This is surely part of what is going on in my car and maybe Shawtys' car as well.

Studiogeek

iTrader: (6)

This was in a post by member Luxor:

Hey all, after doing some research, the steering connector as pictured by original poster is the power steering pressure switch.

The power steering pressure switch feeds information about demand on the power steering system to the vehicle's computer. At low speed, such as during parking lot maneuvers, the engine produces little power. Instead of waiting for the engine speed to decrease from the increased demand on power steering, the vehicle computer can compensate immediately for the increased load demand to keep the engine running smoothly.

The PPS "Progressive Power Steering" solenoid is a valve that varies the flow of hydraulic fluid to a reaction chamber - a fluid force that actually resists the power assistance. If a lot of fluid is allowed to flow to the reaction chamber, the steering effort is higher. If little fluid flows to the reaction chamber, then the steering effort is lower.

Key point: more fluid flow into the reaction chamber equals a higher steering effort.

Controlling the amount of fluid flowing to the reaction chamber is a solenoid. The solenoid (I assume - I haven't cut one open) consists of a coil, a return spring and the valve. When no current is applied to the solenoid, it opens, allowing more fluid to flow to the reaction chamber and so the steering to become heavier.

The current to the solenoid is varied by means of pulse width modulation - the current is pulsed on and off quickly. If it is on for only half of the time (ie it has a duty cycle of 50 per cent) the coil will 'see' only half battery voltage, and so will not close fully. If the duty cycle is reduced to, say, 30 per cent, then the valve will open a little more.

Note that unlike an injector, the frequency of the pulsing is so quick that the valve doesn't open and shut to the individual pulses - instead the plunger hovers at mid-points.

The PPS is controlled by its own dedicated ECU - a little box. It's a relatively simple box, too, with just one input - road speed. As speed goes up, the duty cycle with which it feeds the solenoid goes down and so the valve opens further, increasing steering heaviness. Or, to put it the other way, as the road speed falls, the solenoid duty cycle increases, closing the valve and so lightening the steering.

Here is a picture of the PPS solenoid


Reference:
http://autospeed.com/cms/title_Modif...8/article.html

and

http://www.ehow.com/info_8748803_pow...switch-do.html

Studiogeek

iTrader: (6)

Any Ideas Gents??



BuMp!

Joey-E

iTrader: (1)

Hmm interesting have you tried bleeding the system of air? Maybe that would help or change a little.

Nevermind just read a bit more and you did.

Maybe you got better response from the lines and its more "light" now.

Studiogeek

iTrader: (6)

Or possibly that I HAD lots of air before and the bleed actually "fixed" it instead of "broke" it. Maybe it is supposed to feel this way, and the heavier steering was as a result of air in the system since I got it. It is more quiet now.
I hoped that was not the case but it may be.

fried_rice

iTrader: (20)

My last sc had a leaky rack so the power steering was almost nothing, it was a track car so I had no problem with it. Before my swap I had PPS and it was really light, way too light for my liking. I have the PPS plug disconnected and the braided line and it feels perfect for me with a 5spd.

Edit: I think the DM hose removes the rpm increase via vaccum when you turn the wheel at idle, was annoying for tunning anyways. Just unclip the plug on the steering rack to see if you like it without PPS.

Studiogeek

iTrader: (6)

Hmmmm.
That is surely helpful. I need to do the PS hose anyway. I'll likely give the Driftmotion a shot.

Thank You!

SC4Paulo

iTrader: (2)

yeah my pump was leaking, i liked how it felt, i didn't like how it sounded :/
studiogeek, great info in this thread!

Studiogeek

iTrader: (6)

Thanks kingShawty!
Your input is helping!

I really don't like this. You could sneeze hard and crash this sucker!