1999 Audi A4 2.8 Quattro cranks but won't start
 

Hello, I have a 1999 Audi a4 that won't start. It cranks and cranks but will not turn over. I am aware that this is because my engine isn't getting fuel. I originally thought that it was because my fuel pump had given up. But I found the fuel pump relay, and noticed that it was not making any clicking noise when I turned my key to the on position. I then took the relay apart so that I could manually activate the relay. When I did this, I could hear the pump start to pump, but I'm not sure if it was making the sound it should be making. I then went and purchased a new fuel pump relay only to have it do the exact same thing the previous one was doing. This makes me think that maybe there is an electrical problem. But I know it could also just be a problem with the fuel pump which is causing the relay's not to work properly?

A partial shot in the dark here but try replacing your ignition switch. They're known to be problematic at times and can cause all kinds of screwy issues. Worst case, it doesn't fix it but it's only $25 or so and by replacing it, you may save yourself the hassle of a breakdown later on.

Have you scanned the car for any codes? That's the best first step on these cars when they misbehave.