Re: '91 200q 20v stalls after acceleration & then clutch

[Linus Toy <linust@mindspring.com>]

At 08:00 PM 4/9/97 -0600, Gideon Weisz wrote:
>sometimes (often), if i accelerate rapidly
>and then disengage the clutch (and leave it disengaged)
>the engine stalls.
>1) this has not been repaired by swapping idle control units
>2) i should also note that even when the engine doesn't stall,
>   it fairly often goes down to 250 or 500 rpm, according to the tach,
>   under the conditions i mentioned. my understanding is that that
>   isn't normal behavior either.
>does this ring any bells?

ding ding ding!

check for 
        1) a leaking bypass valve (blow off valve btwn 
                I/C outlet and turbo inlet)
        2) a leaking vacuum control line to the bypass valve  

# 1 is not likely unless you've got high mileage--but it doesn't hurt to
check and clean out any thing in there (should be clean--mine was)

# 2 is quite likely--this is the braided-cloth hose that runs from the back
of the engine (onto the throttle body by the firewall) inside the heatshield
(btwn the wastegate and the cylinder head) then to the bypass valve.  two
typical problems with this hose:  it is too short and gets kinked near the
throttle body where it makes a sharp 90 degree bend) and it gets brittle and
cracks due to too much heat--get enough hose to re-route it to the far edge
of the engine compartment (other side of air box) away from the wastegate.
BTW, the hose is a PITA to remove from the TB--you'll need to remove a bunch
of other stuff in the way, even though you can see/feel it back there.  

As it turned out, this was not my problem, nor was the O2 sensor that I
replaced.  However, this was the first thing Ned pointed me toward when I
reported the same symptoms you have.  But now I know I've got those things
taken care of anyway!

-Linus
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* linus toy                       email:  linust@mindspring.com      *
* mercer island, wa                                                  *
*                                                                    *
*            Insanity is doing the same thing you've always          *
*            done and expecting different results                    *
*                               - Roger Milliken, Milliken & Co      *
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