No pressure in gas tank

[quk@sievers.com (Phil Payne)]

In message <199704141948.PAA05491@pear.epix.net> Karl Devino writes:

> I have an 86 Audi 5000 CS Quattro and I have yet another problem,I had
> all new injectors put in the car when I found gas in the oil.

I hope it fixed the "gas in oil" problem.
 
> Now the gas tank has no pressure.

Don't understand the question. It _shouldn't_ normally have any pressure in it, 
although Audi define a test in which a few millibars are applied (usually from 
a spare wheel) and only n millibars of pressure drop over x minutes is 
permitted.  I'll look it up if you like, but I don't think it's very important 
unless you have a fuel leak.
 
The only area in the fuel system that is supposed to _hold_ pressure is the 
check valve in the fuel pump.  The idea of this is that it allows fuel to leak 
back until the residual pressure in the fuel system is _just_ below the opening 
pressure of the injectors.  When you switch the engine off, system pressure 
should fall rapidly to around 3.0 to 3.2 bar - after about twenty minutes, it 
should still be above about 2.8 bar.  If it leaks back too quickly, the check 
valve needs replacing.  I suspect this is non-trivial on your vehicle, since of 
memory serves the fuel pump (on which the check valve is mounted) is actually 
_inside_ the fuel tank.  If the check valve doesn't fix it, go for the fuel 
accumulator.

> This car is driving me CRAZY

Be thankful it's not an MB ur-quattro.

--
 Phil Payne
 phil@sievers.com
 Committee Member, UK Audi [ur-]quattro Owners Club