Where is the fuel pump in the cadillac eldorado, and can it be change without taking the fuel tank down.

could be problem pressure regulator --stuck open --and not allowing the pump to build pressure

There may be an access panel built into the underbody panels, either under the rear seat cushion or slightly further back in the forward trunk area. That is exactly what they are used for: to get to the fuel pump module assembly without dropping the tank. Under any padding or carpeting, a little round metal plate with screws holding it on. A lot of Buicks of those years had the access plates, a lot of cool imports have had them for years, maybe stop in and ask your friendly Cadillac service technician if your car is so equipped. It is a real time saver, so easy that every owner could do it themselves. Just like changing a fuel filter in the gas tank of your lawn mower, it's almost that easy, compared to dropping the gas tank, now that is a real job, only outgoing optimists should try. I'm retired now from such endeavors, that's all a pleasant (?)memory, but I have sure contributed a lot of vocal outpourings against rust. and the worse the frustration gets, the louder the venting. Alas, why is cursing so common and quick to thought? It took me years to understand timelessness. Yeah, that's it, take your time if you have to drop the tank, it's really not that hard a job, not like rocket science where a bolt takes days to conceptualize, a nice afternoon enjoying the late sun while you change out a ***** fuel pump.

Pull up the carpet and pad in the trunk to see if there is an access cover. If not then you'll have to drop the tank.

Remove the two fuel tank strap bolts
Drop the fuel tank
Remove the pump from the top

Can watch something similar on You Tube Video

Am working on the same problem. Have narrowed it down to a couple of things. The primer curcuit on my '88 is not work off the computer it will not prime the fuel system. Have found away around that by putting in a new relay off the starter line. The main problem though is that the check valve in the fuel pump is shot and allows all the fuel to drain back into the tank. It takes too much time to get the fuel preasure up if the fuel system is completely empty. Am going to replace the fuel pump and see what happens. The fuel pump relay is located under the glove box, have not found diagram map of the relays there, there are 10 there. If you need a wiring diagram for your car, go to autozone, can print off a wiring diagram there. Good luck.

you have to drop the fuel tank its in the top of the tank.

You will have to drop your fuel tank,the pump is inside the tank

You may need to change the fuel filter. If the tank was emptied, the loose sediment on the bottom of the fuel tank probably got stuck in the fuel filter. Change the fuel filter and this ought to solve the problem.

what year?if its fuel injected its in the fuel tank.if its carb. feed its on the side of the block.

The fuel pump is inside the fuel tank.