Hydroboost/ps pump issues?

[AvalancheSVT]

so the car does really great, the only thing is that if i stand on the brakes (like in a way that you'd never do even driving spiritedly) the engine will die if at idle.
its really an edge case so it doesn't bother me too much but i would like to get this sorted.
any body got any ideas? its definitely the hydroboost or ps pump thing.

 

[Mustang5L5]

Do you have U/D pulleys at all?

As you press the pedal the load on the PS pump does increase. As you’ll note, applying unrealistic pressure to the pedal will increase load to the point the engine may stall.

I have hydroboost on my fox and note the same thing but it’s not an apples to apples comparison since mine is a retrofit and I do not have the same pump. I can load up the engine pretty well, but like you said, to do this requires leg pressure that I’ll never use during actual driving. My car stops well with very little pressure which does not load up the engine like it does of I stand on the pedal

I had an 03GT but it’s been years since I had it so I don’t remember how a new, stock new edge behaved.

 

[AvalancheSVT]

pulleys are all stock. there is a pressure relief valve internal to the pump which should open bypassing the pump entirely when it reaches a certain pressure. this is to prevent the system from overpowering the rotor and thusly stopping it (as far as I understand it).

so I set up a test. this is a power drill on the pulley with me pressing the brake pedal inside the car. it stops the pump every time.


View: https://youtube.com/shorts/NFnbvs-JWRU?feature=share

 

[AvalancheSVT]

Why is a pressure control valve necessary on a power steering pump?

Answer (1 of 3): Power steering pumps free flow hydraulic fluid till power steering Assistance is needed by turning the steering wheel. When turning the steering wheel in a hydraulic steering system fluid is restricted on one side of the system and cause the hydraulic pressure to rise on Desired ...

www.quora.com

 

[Mustang5L5]

Do you hear a hissing/buzzing noise from the relief valve prior to the pump load stalling out the engine?

 

[AvalancheSVT]

It was the tune. She runs great now.