[s-cars] Fuel Pump Testing Procedure (for future reference)

[David Forgie]

If you have starting problems and don't know whether its the cam position sensor or the fuel pump,
 you can at least confirm that it is or isn't the fuel pump. Sean D. (quattro20v) and I used this 
technique to test our fuel pumps for delivery rates before we developed the fuel pump relay 
procedure in July/Aug 2004. (Link to relay procedure: 
http://forums.audiworld.com/s4s6/msgs/149790.phtml)

To test the fuel pump, you need a long length of wire with a spade connector at one end, an aligator 
clip on the other end and switch somewhere in the middle - but closer to the spade connector end. 
Once you have that, you need to open up (break) the inlet connection to the fuel rail (hard piping and
 braided hose on the driver's side (left hand drive cars)). There may be some residual pressure so 
only do this when the engine is cold (not a problem if you can't get it started). You need to get a four 
foot long hose over the connection from the fuel pump. Sean had kept a connector from an old fuel 
filter so we attached that to the fuel line and then put a hose on that fitting. Either way, you need to
 get a hose on the connection and be able to run the hose OUTSIDE OF THE CAR to, say, by the
 front wheel. Place the hose in a gas-compatible container. A 2 L measure cup or graduated cylinder
 works well.

With the test fuel line in place, pull the fuel pump fuse, No. 17, from the left hand side dash end fuse
 panel. Stick the spade end of the wire in the right hand side (rear-most) female fuse connector. With
 the switch in the off position, connect the aligator clip end of the wire to the + post on the right hand
 cowl side of the engine compartment. With the hose firmly in place in the measuring receptical, turn 
the switch on for 15 seconds. Then turn it off. At 12v, the fuel pump should have delivered about 
675 mL of fuel in that time (Reference - Pg C20-18 in the Bentley). If you got less, or none, either
 your fuel pump is bunned and you need to replace the pump or there is some kind of blockage in the
 line (i.e. a kink in the hard fuel pump that shouldn't be there). Sometimes, it's a hairball at the end of 
the pump. *This* is one of life's mysteries.

If you need to replace the fuel pump, one procedure is available here:
http://www.elektro.com/~audi/fuelpump/

Hope this helps somebody.

Dave F