stock fuel presure?

I have an '85 euro 911. What is the stock fuel presure supposed to be. It read 40 psi on the guage. Is this correct?

[asphaltgambler]

I don't have a manual at hand but I believe the motronic pressure to be @3bar so you should be OK. Are you having a particular issue with the fuel system?

I'm experiencing knocking @ 4k rpm under full throttle. I'm guessing this means lean running issues. I'm going to check the plugs next. If they look good, what should I check next?

[asphaltgambler]

Knocking (if it is combustion related) may mean many different things. You may have too much spark advance (aftermarket chip?) or a vacuum leak from hoses, gaskets, connections.

You may have just filled your tank with a batch of poor quality fuel, the air-flow meter potentiometer may be losing contact at that very position causing a momentary lean condition.

[rsscotty]

I have only heard a 3.2 knock a couple times.

First thing I would check is fuel quality...if you are not using premium, then try it. If you have a aftermarket chip installed, remove it and install the stock chip. I have sent chips back to Autothority with a pinging issue and have got back a chip with a different timing curve.
Check your spark plug heat range and please post what the engine has in it.

I have always run 93 octane in the motor. I did change brands when this started happening to see if it was bad fuel,...no change. I then ran a tank of Techron through it,....no change.
I am running a Steve Wong chip. However, I've had the chip in for 20k miles and this problem just started happening in the last 300 miles. I am going to put the stock chip back in and run it to see what happens. Before I do that, I'm going to pull the plugs and have a look see. I will also put a multi-meter in the AFM to see if there are any issues there. Thanks again for the suggestions, please keep um commin'.

[Henry Schmidt]

There is a knob for adjusting advance on the side of the ECU that will help you with too much advance / too low octane.

Henry, I completely forgot about that thing. Can you advise on the settings. clock wise versus counter clockwise, how many clicks there are and perhaps an educated guess as to where I should set mine. Thanks much.

[cgarr]

Here is where I found the info. http://www.911chips.com/fuelsys.html

[Henry Schmidt]

Motronic systems are not my forte', but if I remember correctly there is only a 1/2 turn or so and it's only good for about 3 degrees.
Perhaps someone else has some more specific information.

Craig and Henry, thank you both very much for the info. I'm going to try different setting and test it out. I'll post my findings.