Hi , I Have A 1987 Mercury Grand Marquis 5.0 , The Car Ran Out Of Gas When I Got To Work, Right After Work I Put About 8 Gallons Of Gas In The Tank And Engine Will Turn But Not Start. My Buddies And I Checked The Fuel Pump Relay And It Activated When Key Was On , Took Off The Intertia Switch And Bypassed The Wires And Still No Start Also Found A Very Small Pin Hole On Bottom Of Fuel Tank. Maybe The Fuel Pump Went Bad, Tow Car Home And Started Taking Off The Gas Tank , Took All The Gas Out , Patch The Pin Hole On Bottom Of Tank, Took Fuel Pump Off, Bench Tested And It Activates /vacuums As It Should.
I Have A 1985 Marquis For Parts And I Used Its Fuel Pump Which Is Also Working Fine (i Did Not Install The Original Pump From The 1987 I Install This Pump From The 1985) Put Everything Back Together And Still No Start, Reaplced The Intertia Switch With The 1985 Mercury Parts Car"s And It Finally Started, When Car Is Running I Can Hear The Fuel Pump Activating The Whole Time .back Before Replacing The Pump/inertia Switch When I Used To Turn The Key On Before Starting I Could Hear The Fuel Pump Activate Once And Stopped But Now I Can Hear The Pump Running All The Time While Engine Is Running??? What Could Cause This?

 

That is the way it works, runs all the time the engine is running or cranking and for one second when you first turn on the key and not cranking the engine.

 

Ok, Thank You , I Had Really Not Noticed This Noise Before When I Opened The Trunk. (little Too Noise)