Yesterday I drove on a highway at high speed. A few miles later the turbo pressure drop from 1 bar to 0.5 bar.

Later, after stop the car for a few hours the turbo pressure returned to normal 1 bar.

What may have happened?

Today I had another problem. I put gasoline and the gas pointer was in the same! what is the problem?

Thanks,

 

los of boost pressure means you devolped a leak, or possibly a diverter valve ended its life. Take it to a Local independant shop and have a boost leak test done.

the second problem is sometimes if you dont put enough fuel in the car the fuel sensor wont change. do a search on it bunch of threads and info about it.

 

Thanks for your help.

My 996 TT has ECU Tune (1 BAR) and new Forge Diverter Valves.

First I thought in a leak, but now the pressure return to normal (1 bar), so I think isn´t that.

The diverter valves are new.

I put 15 liters. Isn´t enough to move the sensor?

Regards,

 

sometimes leaks dont show until your pushing it multiple times and get things hot then it reseals later just have a boost leak test done they are cheap.

 

Sounds to me car has gone in limp mode and after a few hours it resetted itselve
I had it several times on my car with Forge valves,replaced with Bosch valves and never happened again.

 

15 liters is probably just the limit for no fuel gauge movement. These cars have a weird fuel tank that straddles the front diff. As such, the fuel needle is very strange indeed.

As to the .5bar. I'm betting the car was in limp mode.

 

I bet it i the diverter valves. If you have a bad diverter valve, it may not show itself with a boost pressure test because they usually vent boost to vacuum when they fail. When you check the boost you then are pressure testing the vaccuum system too due to the leak. Pull the small vaccum lines off and the DV vacuum line vented to atmosphere and retest. I bet you will have a leak then. Or you can put a small hose on the vacuum side of the DV and suck on it with your mouth until the internal diaphram actuates and hold your tongue over the hose to block the vacuum. After ~20 seconds if you pull your tongue off the hose and the valve diaphram doesn't slam back shut, you have a bad DV.

 

But after a few hours with the car stoped the problem disappeared.

If I have a bad diverter valve is normal the problem disappear?

Thanks

 

Like I said before your car went in limp (safety) mode and after a few hours ecu resetted itselves.
I had the same on my car and I think the reason was that the divertervalves didn't relaese boost pressure quick enough when you loose the throttle pedal or if you shifted between gears.And when boost builds up for a moment above 1.3 bar ecu goes in limp mode.
Maybe you put the stiffer springs in the DV's or you have a bad DV .
I changed the Forge with the upgrated Bosch ones and never had this problem again.
If you have this problem again just disconnect the battery for a few minutes and
it should be back ok.

 

Hi,

I install the forge DV Valves with the regular spring (I think green colour).

Your bosch DV are like the original porsche? If not, could you send me the link for it please.

Thanks

 

That's most likely a limp mode due to overboost, sensor error or something of the sort. Check the DME for codes, there will likely be one stored that will help you with diagnosis.

 

The fuel gauge send information to the ECU about if there are or aren´t fuel in the tank?

If the fuel gauge is wrong and if there are fuel in the tank, can the car stop? (I can´t find answer for this question)

Thanks,

 

Porsche part #993.110.337.50,
also kown as VW/Audi part #034-145-710A,
also known as Bosch part #0-280-142-108