I have an 88 740 turbo. The main fuel pump is noisy and I don't know what is causing it. When I turn the key on I don't hear the pump come on and on first start the engine takes just a bit longer to start up than normal. So I was thinking check valve, although this doesn't explain the noise, just the harder start and I can hear the in tank pump running but does this mean that it is in fact working ok? How do I decide if my fuel pump relay is working ok? The car runs fine, but if there is something that is straining the pump I want to fix it. I haven't done an FPR test but that is first on the list. Thanks in advance.

J Studer
88 740T 237k