Steering wheel/RPMs????

[Bowman9]

Okay this is going to sound odd.

Standing still listening to the radio with the car idling, I turned the steering wheel to straighten it before going to shut off the engine when I noticed the the RPM's increase. So finding this odd I continued to turn the wheel back and forth all the time the needle is going up and down, not by much but enough to be noticed.

Is this normal? Should I be concerned?
Let me know if the rest of you have noticed this also.

[Marauderman]

Okay this is going to sound odd.

Standing still listening to the radio with the car idling, I turned the steering wheel to straighten it before going to shut off the engine when I noticed the the RPM's increase. So finding this odd I continued to turn the wheel back and forth all the time the needle is going up and down, not by much but enough to be noticed.

Is this normal? Should I be concerned?
Let me know if the rest of you have noticed this also.
Mine has done this since the begining--I take it as been normal --maybe increasing the rpm's to assist the pumps for the steering......my guess......is that possible????

[RF Overlord]

maybe increasing the rpm's to assist the pumps for the steering...

Exactly...turning the wheels while the car is stopped requires much more force than when the car is moving...the PS pump loads down the engine, and the ECM gives it more fuel to compensate, trying to hold the idle at the correct speed.

[RoyLPita]

What RF said.

[TripleTransAm]

I reported this in another thread a few months ago...

If the conditions are right (wrong?) you can almost get the car to stall. I think it's something like having A/C on, being on the brakes, and flicking the steering left/right/left/right real quick... (also, I think I found it easier to reproduce while backing up slowly)...

I actually had a dash light or two come on very briefly, indicating my idle had fallen to disturbingly low RPM...

I'll try to get a more reliable way of reproducing it.

[engine23ccvfd]

Wish it idled up to run the AC compressor :)

[MENINBLK]

Exactly...turning the wheels while the car is stopped requires much more force than when the car is moving...the PS pump loads down the engine, and the ECM gives it more fuel to compensate, trying to hold the idle at the correct speed.

This is *almost* true.

The Power Steering system has a pressure sensor switch inline.
When you turn the wheels, it increases the hydraulic pressure which closes the switch and alerts the PCM to the pressure rise in the Power Steering system.
The PCM then pulls slightly on the IAC to let more air bypass the throttle which raises your idle to compensate.
When you let go of the steering wheel, the pressure drops, the pressure switch opens, and the PCM returns the IAC to its normal position for idle.

This is the simpliest explanation of what happens, and it happens a lot faster than your 3.4GHz Pentium 4 could process it and react.

[TripleTransAm]

Not fast enough, it would seem.

I noticed that it was easier to reproduce this severe idle hunting while the car was actually moving, and while pumping the brakes, making the car jerk (much like its owner ;) ). Explains why I only used to occasionally notice the red dash light out of the corner of my eye as I'd inch backward while turning out of my parents' driveway onto a rather busy street.

No big deal for now... but if my car ever stalls on me from such a mundane operation as what I've described above, it'll be a death blow to my opinion of the low end on this motor (I still think the 550 rpm idle is a nod at fuel economy, since this car guzzles so bad at idle compared to my other cars with much bigger motors).

It can also be frustrating when negotiating the car into a tight spot in a parking garage with many pillars around... the little surges from the changing power steering effort are REAL eye-openers on some mornings...

[MENINBLK]

Not fast enough, it would seem.

I noticed that it was easier to reproduce this severe idle hunting while the car was actually moving, and while pumping the brakes, making the car jerk (much like its owner ;) ). Explains why I only used to occasionally notice the red dash light out of the corner of my eye as I'd inch backward while turning out of my parents' driveway onto a rather busy street.

Pumping the brakes reduces the vacuum in your intake manifold which reduces your idle quality.
When the car is coasting slowly enough to reduce the transmission idle load on the engine this also reduces your idle quality.
Add to this your playing with the steering and I can understand why your engine wants to stall.
Your PCM is trying to keep up with all of these changes and apply what it thinks
will counteract all of them, and it will not correct all three events.
If your problem is reproduceable, you may want to contact your dealership so that they
can capture a data stream from your PCM while this happens, and submit it to Ford Technical support
so that they can correct it in a future PCM Firmware upgrade.