'91 Steering hang-up

[SHOdad]

I have noticed recently on my '91 (120k miles) that the steering will catch or hang up momentarily when I turn sharp to the left, especially when cornering hard at high speed. Anybody have any ideas what the problem could be and how to fix it?

 

[ThrillSHO]

Sounds like your VAPS (variable assist power steering). At low speeds there is max assist, at high speeds there is very little assist. The amount of assist is controlled by a stepper motor that varies an orifice valve.
First time it happened to me, it was a bit unsettling. Entering a hairpin at 70+, braking hard then turning hard - it felt like my steering had locked up. It happens because the stepper motor can't open the valve fast enough. Under "normal" driving it's rarely a problem. The fix is to insert a switch in line with the stepper motor and shut it off at whatever amount of assist you like. It will stay there until the switch is closed again - regardless of speed.

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ThrillSHO Racing
93 ATX SHO
UDPs, LPM, 80mm MAF, K&N w/CAI Snorkle, 8mm Taylor wires, Koni Struts, High Rate Linear Springs, Camber plates, Adjustable rear control arms, Touque box brace, Poly bushings, 24mm front SB, 26mm rear SB, Alum SFB, Full-length SFCs, Front STB, SS Y-pipe, Borla Cat-back, TransGo Shift Kit, Relocated battery, Five point harness, Five 2" gauges below the CD player, 225/45s on 16x7s
Very Low Very Fast

 

[sdpatt]

The '91s did not have the variable power assist. You can definitely "beat" the power assist using rapid turns of the steering wheel. I have been able to catch the power steering not willing to move as fast as I have asked, but the car wouldn't have been able to make the change of direction without tire slippage anyway. Make sure that your fluid is full and the accessory belt is not slipping.


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Scott

1991, 252K miles, glass hood, police grill, SVO shifter, Catz fogs,
K&N, 73mm MAF, Superchip, PP Y-pipe, Borla cat-back, 190 lph pump
Eibach/Tokico/polyurethane, SHO Shop front & rear strut braces,
16x7.5" Moda R1, 225/55ZR16 Bridgestone RE730, -1 deg camber x 4,
Class II hitch, Silver award at the SHOklahoma Car Show

 

[RStalveyARFF]

I have the same problem also, when the car is cold, there is a "****" almost that will give you feedback, and once you muscle past it it's fine on that side, turn the wheel back and you hit it, and it goes the same way.

 

[WaterRooster]

How do you install that switch, cause mine does the same thing



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Shawn
93 Emerald Green MTX
CAI,PP Y-pipe, Dynomax Catback, 80mm MAF, LPM, Ebachs and Tokis

 

[smokesho]

same here, i've noticed that as well, and at first i thought it was bearing related....

 

[ThrillSHO]

There's a pretty good write-up on SHOtimes about VAPS and installing a switch. http://www.shotimes.com/SHO4VAPSadjust.html

 

[SHOdad]

Thanks for the info!