[urq] hunting down 4k rpm cutout, idle sw & intake temp OK

[Buchholz, Steven]

... mark me down for being skeptical that the OXS Freq Valve connector
would cause a 4k RPM cutout situation.  I see where you are getting that
suggestion ... from Ned's site ... I don't see the connection with a *4K
RPM* shut down, but it can cause problems ... read below.  

I had a weird one on my car ... it seemed like the ignition cut out at
4k RPM, but it is not documented as a cause.  I verified the static
timing for the crank, cam and distributor and found the dizzy wasn't
lining up exactly.  When I lined up the distributor better the problem
disappeared.  Could the Hall Sender have been set up marginally and the
TDC signal went out of the Hall window?  It seems a bit of a long shot
to me ... 

The IST docs indicate that a faulty IAT sensor or idle switch (always
closed) will cause the engine to limit the RPM to 4000.  Have you
checked out the boost curve?  I think if the ECU sees too high a boost
over a certain RPM band it will shut off the fuel.  

I did have one problem related to the OXS Freq Valve circuit.  The car
would start and idle fine, but would stumble and die any time the
throttle was opened even a small crack.  Eventually I correlated the
occurrence of this phenomenon with a lack of the buzzing noise from the
OXS Freq Valve.  It was an intermittent on my car ... perhaps you have
an intermittent with yours too ... I traced the problem down to a
failure inside the ECU (F/TCU).  

Steve B
San Jose, CA (USA)
> 
> I'm off to the stealer to pick up a new connector and pins for
> the FCV, here's why:
> http://www.istari.com/public/urquattro/maint/cutout4k/index.html
> Any bets I won't have to ascend PP at 3600 RPM if I replace the plug?
> 
> I'm actually fishing for ideas if this doesn't fix it, ones other than
> the IA and SJM
> pages I linked to in the above web page.  I'm also wondering if
> everybody's valve
> is crammed against the wheel well like mine, or somewhere you can get
> the plug
> off without disconnecting the fuel lines for access.