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Power Steering Switch/Relief Valve

11-29-2009, 08:11 PM
I read reference to a Power Steering Pressure switch/relief valve that affects the idle while turning hard. My wife's 98 - 3.8L is experiencing the occasional engine stall during low-speed hard turns.

I have not been able to locate this switch/valve in any of the documentation I have, nor I have I found details searching here.

Any suggestions on where it may be located and how to test it?


11-30-2009, 09:08 PM
Well....the most common cause of the problem that you are having is a sticking Idle Air Control Valve (IAC).
This is mounted on the upper intake manifold, near the throttle body....held in place by 2 small bolts.
Remove these bolts......and lift the unit off......unplug the electrical connector.
Then....Clean the unit out with Sea Foam "Deep Creep", which is the spray version.
You can also use WD-40.
Hold the IAC unit so that the fluid will run out as you spray it inside.
The idea is to flush the dirt out......leaving the screw drive inside oiled.
Then reconnect the electrical connection.....and re-install using the 2 small bolts.

As for the power steering pressure switch.
AlldataDIY shows this on the steering rack....."next to the steering gear".
I was unable to find it on my '96 windstar, in spite of seeing it listed on Alldatadiy.
It may only be on certain applications?

12-01-2009, 08:11 PM

Thanks for the reply. I'm curious about the IAC also, except that I've been monitoring its response during cold-starts and appears to be working correctly. The engine cold starts and immediately idle jumps to around 1100rpm for a short time. It then properly settles to about 800rpm.

I'll follow your suggestion, I was just curious why its not misbehaving in all conditions.


12-01-2009, 08:21 PM
I noticed mine acting up during parking lot manovers.....low rpm....varying load on the motor.
I guess a vaccum leak can cause this also.

12-05-2009, 08:31 PM

I did the cleaning of the IAC while I was in replacing the EGR and PCV valves. The car has 150K, so for the price I just decided to replace them. I reviewed all my service records and neither had been done. I also replaced a dry and brittle hose running form the PCV 3-way connector to the EVR (?) valve that sits centered on the firewall.

So far I'm still getting occasional rough idle, and some dieing at low parking lot speeds. I haven't gotten any codes yet, but only been driving it a day. The last two codes I had were the 0303 & 0171, but It will have the problems above long before the codes show again.

My next check is going to be a compression check. I want to get an idea what shape the mechanicals are in.

12-06-2009, 07:03 AM
You may be due for a cleaning of the EGR ports in the lower intake manifold.
They tend to start clogging on the driver's side first....leaving the ports for #3 and 4 they get all the EGR flow....causing those 2 cylinders to be starved for oxygen.....causing a misfire.
You have to remove the upper intake manifold to get to them.

My '96 seems to require an occassional treatement with Berryman's B-12 the metal can.
This cleans the fuel injectors up.
I have tried many other products....but, for me, ONLY the Berryman's seems to do the job.
SO....I would recommend you give your gasoline tank the can of the Berryman's to clean up the injectors.
I also recommend that you replace the fuel filter, if not done within the past year or so.
A fuel filter that is clogged.....or restricting the flow will place an additional workload on the fuel pump.

12-07-2009, 06:53 PM

The ports you spoke of in the lower intake manifold, are these the two ports that are fed by the bracket the EGR valve is mounted to? I cleaned the bracket and replaced the EGR valve but didn't think the intake ports themselves would need cleaning.

Do these ports run the length of the manifold and feed all cylinders (as I would expect)? If so, then I would need something semi rigid to feed through the port to get both ends - correct?

Any diagrams that show the routing of these ports?


12-07-2009, 09:08 PM
These ports are inside the lower intake manifold.
To clean them, you have to remove the upper intake manifold, which is the big black part.
The lower intake manifold is alluminum.
Here is a picture, with the upper intake manifold removed....which shows the clogged ports.

From the EGR valve.....the exhaust flows through hollow passages inside the lower intake manifold.....entering the intake at each cylinder......through a 1/4 inch port for each the port that does NOT have the IMR plate.
These ports ONLY clog right where they enter the intake seems that when the exhaust meets the oil vapors from the PCV creates this junk that clogs the EGR ports.
No need to clean down in further than the very the port.
You can clean them by using a small screw driver to loosen up the crud....and a shop vac to suck it up.
You want to avoid getting anything on down into the use care when cleaning.
If you go crazy and spray cleaner......and let it run down....all the crud will be drawn into the cylinders when you go to start the motor.......which would NOT be good.

Here is a big view.....showing the lower intake manifold with the upper intake manifold removed.

Note that the fuel rail does NOT need to be removed to clean the EGR ports in the lower intake manifold.

Sadly, there is nothing you can spray into the intake or add to the fuel to clean these......the only way is to remove the upper intake manifold and do it by hand as mentioned.

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