99 chevy silverado Z71--replaced the fuel pump and it still will not crank,sprayed a little starting fluid in throttle body and it wanted to start,checked the fuel filter and it was good,and swith the fuel relay around with another relay and it still would not start,and could not find a fuse for the fuel pump what else am i over looking...Henry

First you need to determine is it is electrical or fuel. Spray some starter fluid into the throttle body to see if it will start. If so then the problem is fuel related. If not, check for spark at the plugs and signal to the injectors. A scanner would really help to pinpoint the reason.

Spray some starter fluid into the throttle body. If it runs then check the fuel system. Fuel pump, relay, fuse. Make sure it has fuel in the tank.

First thing I would check it the fuel pressure at the rail. You can spray some starting fluid or carb cleaner into throttle body. If it want to fire it is most likely the fuel pump. If it doesn't try to fire it is most likely ignition related. Good luck

Could be a clogged fuel filter or a bad fuel pump..

Did you check the fuel pressure before you replaced the pump ?
Can you spray carb cleaner or starting fluid into the throttle body and make the engine want to start ?
If it is throttle body injected, can you see the fuel spray when you crank it hot ?

Sometimes you can straighten the little rod to have it close better using a pliers

Sounds like the fuel pump is bad

Have you checked the fuel pressure? Fuel pumps are a common failure item on those trucks. Pick up a cheap fuel pressure gauge and hook it up to the shrader valve on the fuel rail. With the ignition on and you should have 55-65psi. Even if it's a few psi below spec it could stop the engine from firing.Once you determine the fuel pressure isn't adequate make sure you have a good power and ground at the fuel pump. If that checks out, time for a new fuel pump module. I recommend only replacing it with an AC delco unit, I've heard bad stories about aftermarket replacements.
You could also spray some carb cleaner or starting fluid in the throttle body and crank the engine over. If it runs for a few seconds after spraying starting fluid in you know you have a fuel delivery problem.

check then crank positon sensor, it control the fuel system. it tell the engine computer when to send fuel

Possible weak spark from ignition coil or low fuel pressure due to weak pump. Try spraying carb clean into intake throttle body when problem is present. If vehicle will start and run with a little spray then fuel pump is failing.