Daytonaman

Hello all, pulled in shut it off and when started a month later would only run even >2,000 rpm.
Started normally but in a min died; won't idle.
Will restart but only runs above 2k.
Fuel pressure 40psi only after startup.
CEL. came on with a P0001 trouble code : "Fuel volume regulator-control circuit open"
No other issues until now.

Carlo_Carrera

Sounds like a possible fuel pump issue. Specifically a split hose at the top of the pump assembly.

Kevin

I agree with Carlo.. You should be near 55 psi at idle. If your car hasn't had a new pump assy installed >>order one up. Call Sonnen Porsche 866 Sonnen1 Neil, Gina or Ryan

Daytonaman

Thanks to Keven and Carlos
Fuel pump split hoses were discovered and repaired with proper approved fuel line 100 mi ago.
FP is constant @ 3.8 bar at any rpm including idle. No leak down.
The engine runs an over rich condition; smokes @ idle and dies.
This relates to the "fuel volume control circuit open" stored code.
Looking at the fuel system on the Bosch 7.8, it looks like there are 2 fuel pressure regulators on the rails.
The 3.8 bar FPR is on the right engine fuel rail and appears to hold FP @ 3.8 bar.
This regulator has no connections other than a small vacuum line out of the side.
Since there is no fuel tank return on this system, it is unclear how this reg functions.
The other sensor is a fuel volume sensor also located on somewhere on the engine but cannot locate it.
This control circuit apparently gets a signal from the ECU that somehow modulates the FP to control low fuel delivery at low demand.
The error code seems to relate to that circuit.
Currently I was going to just replace the 3.8 FPR even tho I now know that might not be the problem.
I have not seen any fuel volume sensor problems on this site, and don't know how to troubleshoot that circuit
Am I still looking to change the FP?
It is possible that fuel delivery control is actually built into the pump.
Thanks to this board.

Carlo_Carrera

Total shot in the dark, disconnect the MAF sensor and start the car. Report back.

T10Chris

Not much of this right.... recommend taking your car to someone that knows what they are looking at, learning on a fuel system isn't the safest idea.

There is a return line back to the tank. The pump doesn't have any fuel delivery control built in. There are no electronic controls in the FPR, it is a simple manifold pressure reference regulator. There is only 1 FPR. There are no sensors anywhere in the fuel lines/fuel system that monitor flow... etc etc

I'd clear your codes and see if you get anything new or if that fuel control code comes back as active. I've never heard of the fuel volume control circuit code... what is the actual P#### code it is giving? I don't know what you are using to read codes but a lot of times the generic code readers give a generic answer, but Durametric or PIWIS will tell you something more specific.

Daytonaman

Sorry Chris, your right; I was using the NA Carrera fuel system drawings instead of the 996tt.
The Carrera has no return line and an electronic FP w/ ECU control flow rate.
Turbo has a return.
I'm gonna replace the FPR and try and unplug the Mass Sensor.

Carlo_Carrera

Do things one step at a time so you know what is going wrong. Try unplugging the MAF first.

Daytonaman

Thanks Carlo, I unplugged the MAF and car will and idle, and run ok, but smokes a little.
Clean/replace the MAF?

Carlo_Carrera

Yes, try cleaning the MAF first. What color is the smoke?

Daytonaman

White.

Carlo_Carrera

Did it go away after you ran the car for awhile?

Daytonaman

Hey thanks Carlo; car runs significantly better with the Maf unplugged. Still loads up and smokes on idle.
Engine will run above 2k rpm but dies on idle after it loads up.
Removed Mass sensor; looks brand new. Car has 39,00 mi.
Might purchase a Durametric to see what is going on.
Don't want to flat tow it to a shop just yet.
There are no qualified shops in Daytona anymore so I would like to narrow the problem
Car ran perfectly for years until the failure.
Might replace Maf sensor?

Carlo_Carrera

I would clean the MAF with MAF cleaner first, then reinstall and see how it runs. And yes, try and pull some more codes and data.

What part of Daytona are you in? My family has a house on S Atlantic down in Wilbur.

Daytonaman

Going to clean the MAF; CRC MAF cleaner
Wilbur is quiet and beautifull;
I'm up by Belair Plaza.
Where is the best place to purchase a Durametric for the 996tt; I just have a generic reader.