Q: 2001 BMW 740il fuel pump replacement

If the pump has failed, depending on the failure mode of the pump, you can diagnose the fuel pump yourself. Turn the key to the ignition (run) position. At that instant, you should hear a momentary whirring noise from the fuel tank (you must be in fairly quiet environment) as the fuel pump pressurizes the fuel lines. The whirring will be quick. If you hear nothing, then check for battery voltage on the harness that plugs into the fuel pump. If there is momentary battery voltage at key on, and yet in the prior step the pump did not function, you probably have a dead pump. You can also power the pump directly just using a battery to get additional confirmation. If you apply power directly to the pump and you hear nothing the pump is dead. This only covers the "pump is totally dead" failure mode. The pump can make noise and not pump fuel. To test that, you just look for pressure on the fuel rail. YourMechanic performs mobile repairs and diagnostics and a diagnostic on your issue, and any required repairs, can be performed right at your location. If you desire that service, just request a no start diagnostic. With regard to Ebay, that can be hit or miss when it comes to automobile parts. I have had a few notable misses. Unless you buy a lot of auto parts on Ebay, and thus are familiar with the significant and meaningful risks (junk, expired products, counterfeits, gray market, store returns, damaged goods, and on and on ad naseum), I wouldn’t recommend a fuel pump for a BMW as your first experience. Furthermore, brand new parts can be cheaper at retail than Ebay now. Ebay is not necessarily a bargain and an item such as a fuel pump would be a risky purchase. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.