From: Jay Kempf [jkempf@tds.net]
Sent: Thursday, May 30, 2002 5:51 PM
To: 928
Subject: [928] RE: Won't Rev - "Valet Mode"

Charles,

I think what you are telling me is that you have a minimum of 3.0 bar at
idle at your WUR regulated. That is about 44.1 psi so it is ok but it
shouldn't vary after the car is warmed up. It should start at around 20-25
psi on a cold morning near freezing. Somewhere between 25 and 50 depending
on temperature and it should top out at a setting that is above the injector
opening threshold about 50 psi. The system pressure needs to be around 65
psi minimum or 4.4 bar so it looks like you are fine there and your volume
test looks good. Bar is about 14.7 psi btw.

But.... It sounds to me like your WUR is varying pressure with RPM and that
ain't right. That means that either it is not "regulating" a steady control
pressure or the system pressure regulator is not adequately providing enough
flow/pressure to keep ahead of demand. That is where I would start. System
pressure regulator putting out a rock solid minimum 75ish psi. Clean it and
put it back in. It is on the side of the Fuel Distributor body drivers side
back. Careful not to scratch anything. My theory is that it is providing a
good restriction and pressure at idle then when it needs to open for larger
throttle settings it is sticking. If this is true you should see the control
pressure drop to below 20 or so psi as you open the throttle. leave the
gauge on and drive the car. It won't hurt it.

Next, your timing I think should be nearer 30° with all vacuum advance
disconnected. That could be an issue. If I am confusing 79 with 80 I
apologize. but I run mine near 32° just on the edge of pinging and it ripps.

Last your mention of vacuum. Don't worry about that. That normally only
effects idle and smoothness by introducing false idle air. Like trying to
shut down a woodstove. Should be masked at WOT so would be causing the lack
o power.

I would start with fuel pressure at the system regulator. Then WUR to make
sure. Then timing. Then vacuum leaks. Take em one at a time and you'll
probably get there.

Jay K.

>-----Original Message-----
>From: Charles McGuire [mailto:cfm_studio@NetZero.net]
>Sent: Wednesday, May 29, 2002 10:12 PM
>To: 928
>Subject: [928] Won't Rev - "Valet Mode"
>
>
>I drove out to LRP in "valet mode" last Fri to catch the practice
>for speed
>channel, and had a chance to observe Mark A's white car exiting West Bend
>at speed. What an awesome sound!  Also impressive was comparing the action
>in the paddock: Other crews were all over their cars repairing and
>changing
>things, Mark simply changed his tires and went for a bike ride!
>
>My car is still in need of a "CIS expert". (VT Jay perhaps?) I've
>done some
>more testing, and can rule out some items, but if I can't solve this soon,
>I may have to break down and take it to a shop. Can anyone
>recommend a shop
>in S. NH that still remembers CIS and semi-OB 928s? Here is the info for
>anyone that wants to venture a diagnosis, next step:
>
>The car ran great for a week, but now is exhibiting "valet mode" symptoms:
>At WOT it takes forever to get to redline (1st or 2nd gear). Press slowly
>and it will eventually get there . I've checked for vacuum leaks (using
>WD-40, carb cleaner, etc. It pulls 15-16 in. Hg at idle, a bit low?
>Retarding the timing brings it up to 17ish.) (Cam timing marks are right
>on, timing light is right on, advances to 20 deg BTDC.) Fuel delivery is
>1700cc in 30 sec. (spec. is 1350cc). Warm up regulator is closed when car
>is warm. I put a fuel pressure gauge (couldn't get the one shown in shop
>manuals with the switch) on the pressure regulator: it shows 3 to
>3.6bar at
>idle. Is this OK or low? Manual says 3.4 to 3.8bar with vacuum on intake
>pressure connection of pressure regulator; then it says system
>pressure 5.2
>to 5.8 bar. What should I have there? (ie I inserted the gauge in line on
>the input side of the control pressure regulator as per the manuals.)
>
>Even with 100 "missing HP, it's still more fun to drive than half the cars
>on the road!
>
>Charles 1980 Euro 928S in temporary valet mode
>
>
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+++
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