Throttle Valve Dashpot Question

[Huw Powell]

> My Canadian 5TQs both have a "throttle valve dashpot" as shown on page 25.29
> of the Bentley manual.  I do not know if US cars have these.
>
> Does anyone know what they are supposed to do?  I assume they are like the
> dashpots on carbureted Fords and control the speed at which the throttle
> closes when you take your foot of the accelerator.

that's what the one on my 90 looked like to me.  it simply slows that
last bit of closing throttle motion.  which seems silly, since once the
idle switch gets closed, the ECU kills the fuel for a moment to save on it.

> However, the dashpots on both of my cars don't dash or pot.  They have no
> resistance at all except the slight spring pressure which certainly cannot
> control the throttle closing speed..

I took mine out.

> I have been having problems with one car stalling on idle (only when the car
> is really warmed up).   The revs drop quickly to ~ 300, then recover in a
> second or so to the correct 800.  Sometimes.  At other times the idle speed
> does not recover and the car gradually stalls (in about 2-3 seconds).

I don't think that is your problem.  Like I said, I took mine out and
basically noticed no change, other than a .03% increase in power due to
reduced weight.

have you measured your idle switch yet?  it is usually on the bottom of
the throttle body, and it tells the ECU to save fuel, but also to use
the ISV to hold an idle.  Without you could get a high or low or erratic
idle.

--
Huw Powell

http://www.humanspeakers.com/audi

http://www.humanthoughts.org/