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

[Charles Baer]

I did one thing last night in the interest of identifying the cause of
the cutout: replaced the wiring from where is was butt-spliced
to the rest of the harness on out to the plug.

No cutouts on the way to work this morning.

It's not conclusive yet.  When I drove to work one day last week
it was OK in the morning but the drive home after the heat of the
day was a solid 3800RPM snafu.

Charlie


Buchholz, Steven wrote:

>... 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?
>>    
>>