nrgetic99

In running to ground a vacuum leak, I found a pair of hoses on the PS pump attached to a vacuum switch on my 93 V6.

One side goes to the air inlet downstream of the VAFM and the other goes to the inlet plenum vacuum.

I am assuming this is another 'idle up' device to keep the idle up when the PS is used at idle ....such as pulling out of parking spot etc.

The only difference vs the AC idle up valve is that the AC version is only active when the AC clutch engages and also has a flow valve in the system which allows you to trim how much the idle comes up. The vac switch on the PS pump is just a fitting with two barbs on it screwed into the body of the PS pump with no visible electric actuator or flow valve.

Anyone confirm as I cannot find any mention in the FSM's I have access to.

Thanks

David

mt_goat

I seem to remember (barely) a valve internal to the pump that actuates when the pump pressure is high, but I'm not sure about that. It has been about a year since I rebuilt my PS pump.

nrgetic99

Thanks for the tip....

...actually, I just got a good hit and found a description of the system which states " An air control valve increases idle speed when the power steering pump is loaded"

So...there you have it !

David