[s-cars] Re: S-CAR-List Digest, Vol 11, Issue 15 Low Boost when engine is warm - please help!

[Larry C Leung]

Fred, Taka, Calvin,

Scott Mockry has the procedure on how to do this on
at least the 10V diagnostics page. It's actually quite
simple to do (literally connect the LED across the 
voltage leads to the WGFV, keeping in mind the 
polarity, no big deal, if you're wrong, the LED won't
light.) I've done it on my 10V, there are just two issues.
1 - it's VERY difficult to see the LED except at night
2 - if you want a general idea, it'll work, but once the
boost pressures get much over atmospheric, the light
is blinking so fast to the point it looks like steady light. 
Don't know if it'll discern the diff between 9 psi and 14 psi
boost.

LL - NY


> Date: Sun, 5 Sep 2004 07:38:37 -0400
> From: "Fred Munro" <munrof at sympatico.ca>
> Subject: RE: [s-cars] Low boost when engine is warm- please help!
> To: <calvinlc at earthlink.net>, "TM" <t44tq at mindspring.com>,
>         <s-car-list at audifans.com>
> Message-ID: <ELEILALKJKMBKDDGOMAIOEKHFAAA.munrof at sympatico.ca>
> Content-Type: text/plain;        charset="us-ascii"
> 
> I recall Phil Payne had wired a LED into the WGFV circuit and 
> estimated the
> duty cycle by how fast the LED was flashing. That may be a cheap and 
> easy
> way to check the WGFV function.
> 
> Fred Munro
> '94 S4
> 
> 
> -----Original Message-----
> From: s-car-list-bounces at audifans.com
> [mailto:s-car-list-bounces at audifans.com]On Behalf Of
> calvinlc at earthlink.net
> Sent: September 5, 2004 12:29 AM
> To: TM; s-car-list at audifans.com
> Subject: RE: [s-cars] Low boost when engine is warm- please help!
> 
> 
> Taka,
> 
> With a hard problem like this I guess I would try to get ahold of a 
> portable
> oscilloscope or a multimeter that measures duty cycle and tap into 
> the
> wastegate control signal.  Compare the duty cycles when you are cold 
> and
> everything is working properly to when you are warm and boost isn't 
> getting
> up to full.  You could then isolate between a problem not allowing 
> the car
> to get to full boost mechanically or a problem with the computer 
> not
> commanding it to full boost.  If it is the computer then check each 
> and
> every sensor's signal with the O-scope while driving (two person 
> job
> preferably).  If it is not then I would start by swapping the WGFV 
> with a
> known good one.  Good Luck!
> 
> --Calvin
> 
> 
> 
> -----Original Message-----