Hi I hve a 1994 Mazda Protege thats having a fuel pump problem replaced fuel pump checked all ground wires replaced fuel injection relayreplaced pressure regulator can hot wire fuel pump and car will start

check fuel pressur, filter and fuel pump...sounds like it isnt getting fuel

bad fuel injectors. bad spark plugs - inspect and or replace -- bad spark plug wires - test ohms resistance of the spark plug wires with a multi meter (5 bucks at harbor freight) -- or simply replace the spark plug wires.
How was it you tested the coil and spark at the plugs?

I'd lean more towads faulty fuel injection, if you go to repai this, please be sure to add a quality fuel tank cleaner like lucas (the larger the bottle the less the cost per ounce - and works VERY well), You may also want to be sure to replace the fuel filter...
Best regards
Ck

fuel injected cars cannot vapor lock, so not the issue, when they replaced the fuel tank did they replace fuel pump? It should have been, but 2 things come to mind, they pinched wires when putting tank in and it shorts sporadically shutting off pump, look around with light and trace wires looking for any breaks in plastic coating, or fuel pump is failing.

TRy replaceing fuel filter.

Listen for the fuel pump to turn on with the key ON. Do you hear it buzz on for a couple of seconds, and then shut off? If you do, the pump is working. If you don't hear it, the pump is bad or the wiring to the pump is not working. Check the relay.
Usually, on a four cylinder with multi-port injection, injectors 1 and 3 fire simultaneously, and then injectors 2 and 4 will fire at same time (because their ground wires are spliced together before entering the computer. When the computer internally grounds the wire, the injectors will pulse). Are you certain that all four are pulsing at same time? If so, that may be the Mazda way. But I think you are right to believe it is a fuel problem. Test the pump as stated above, key on (not start) and listen for pump to turn on.
Good luck.

disconnect the battery cables and undo the belts from your tank drop it and it should be right on top a couple of wires see how they are connected connect them the same way thepump it kind of locked in to the tank you should see a ring you turn to release the pump the pull it out replace it and put it back on just like you take it off.

TAKE OUT THE FUEL FILTER,PUT NEW ONE AND TRY,IF DONT START , TAKE OUT FILTER AGAIN IF DRY THEN FUEL PUMP NO GOOD

u mean the injectors are not working/suppling fuel to the engine? or do u mean the fuel pump is now inop, please explain./

Hello, I am going to make a few assumptions here. The vehicle has an electric fuel pump and you replaced it. The vehicle has fuel injection. The engine is actually cranking, just not starting, when you say "car still won't crank". You are getting fire to the spark plugs at the plug ends. You checked the fuel pump for power at the pump. No power, then you back traced the wire to the fuse block and checked the fuse to see if it was blown. If the fuse is good back trace the power to the ignition switch and/or ECM for power. You have power at the pump, check the ground and make sure it is connected properly. Will the pump run when someone turns the key on? Pump runs, check fuel manifold for pressure. No pressure, check the fuel filter for blockage, or replace it. Fuel pump doesn't run, new replacement pump is defective. There is usually some type of control module for the fuel pump on fuel injected vehicles. Good Luck, RAC