Saga continu.... 100q wont start now

SJ syljay at
Thu Dec 16 23:06:13 EST 2004

From: "Denis" <sparkplugvw at>
To: <quattro at>; "SJ" <syljay at>
Subject: Re: Saga continu.... 100q wont start now

  That s the reply i was expected. I saw somewhere a good explanation of the
CIS-3,,, lost it..

  There is ,,, i have a way to go...
  I ll begin at the beginning.
  Check where the fuel start..... filter in the fuel pump.
  Check the fuel line under the car.

  If its ok... then the regulator.
  I have an extra from a 5000T 1985.

  So the fuel pump is almost new, it should be ok. As you said the regulator
might not working propelly.

**** Assume nothing!

  One more question:
  The fuel  pressure drop instant... at 20 psi when i stop the engine.... is
not suppose to be maintain longer ?

***** Hmmmmm. If you have a problem, the fuel in the pressurized system can
go two ways when you stop the engine.
1. back thru the fuel pump and into the tank. But the fuel pump has a check
valve to prevent that.
2. Back to the tank thru the pressure regulator. But that is set at 90 PSI.
Any pressure under 90 PSI will shut off the regulator.

You are not clear regarding the 20 PSI drop. Pressure drops to 20 PSI and
stays there? Or does the pressure drop by 20 PSI and stay there . . 60 psi -
20 psi = 40 psi ?

If this 20psi stays constant, then its not likely to be the check valve.
Although it could leak only under high pressure and stop leaking under low
The only thing that maintains pressure is the pressure regulator. If you
have a spare regulator, swap it in.

The Bentley has a procedure for checking the fuel pump when its in the
1. Disconnect fuel return line at connection(just in back or side of fuel
2. Insert fuel return line into beaker or container.
3. Run fuel pump for 30 seconds
4. pump will pump out 450 cc's of fuel into beaker

You need to measure the voltage at the fuel pump. Fuel amount is a function
of the voltage at the pump. Who the hell knows, maybe you have high
resistance in the electrical circuit and very low voltage at the pump!
Normally, the voltage should be 10 volts when running the fuel pump.
450cc at 10 volts
590cc at 11 volts
760cc at 12 volts

85 Dodge PU, D-250, 318, auto
85 Audi 4k - - sold but still on the road
88 Audi 5kq
90 Audi 100q
  I did that today:

  At the tank 1/4 i added 99.9%alcool in case of water...
  Changed the batterie; the starting procedure got my batterie. Now it spin
the engine very well.
  Changed fuel filter.
  I ll partout the turbo distr. to get the reg.
    ----- Original Message ----- 
    From: SJ
    To: quattro at
    Cc: Denis
    Sent: Thursday, December 16, 2004 10:08 PM
    Subject: Re: Saga continu.... 100q wont start now

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