got a problem

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I have a 1996 2500 chevy pickup with a 454. yesterday i went to the mall, it was running just fine, but when i tried to start it back, it wouldnt. the starter turns but the motor wont turn on. i thought maybe i flooded it so i waited a while. still wouldnt start. then i noticed the fuel pump wasnt coming on. so i figured it was either that or the fuel relay. i bought a new relay, wasnt that. so i bought a new fuel pump and put it on. still wont work. usually when i turn the key on it will come on for about 2 secs then shut off. its not coming on at all. ive tested all the connections and fuses. theyre good. does anyone have any idea why my fuel pump isnt coming on? ill probably have to take it to a shop but if its something i can fix i'd rather do it myself. thank you for any help you can give.
 
My Dad has a GMC 454 and has similar problems. The engine cuts in and out, but the problem isn't as constant as yours. He just gets the pump replaced and it works for a while.
 
This isn't meant as an insult or a joke or anything, it's just that it's easy to overlook the easy solutions sometimes.

It has gas in it right?
 
haha ya it has gas. after i put the pump in it i noticed there was hardly any gas. i went and bought 5 gallons and it didnt make a difference. i would have been pissed at myself if that was all it was. well i was reading my manuel and they said to test the sending unit. im about to go test it. if its not that then i guess ill have to go to a shop.
 
You are kind of asking two questions here:

1) Why isn't the fuel pump coming on?

and indirectly:

2) Why isn't the car starting now?

Since the first was the more direct question:

If as retsmah pointed out, you have gas and you are quite sure it is "good" gas (ie: not tainted, bottom of the bucket condensate saturated, rust from the tank, other contaminated gas) then you are starting in the right areas although, I think you should disconnect the gas line up at the engine (before the injection system and safely check to see if you are getting gas there first. There are many ways to do this ranging from an inexpensive fuel gauge to just pumping a little into a bucket or something.

In so doing, you have just isolated whether you have a bad pump or not. If you have the proper pressure at that point, then you need to look elsewhere. This could mean you still have a fuel issue resident in the injection system or it could mean you have no spark (electrical).

It could be the pump is not coming on when you turn on the key because the pressure is high enough in the line the pump is being kept off on pressure. Just because you bought a new relay or new pump doesn't mean they are good either.

If it is actually electrical problems feeding the pump: You say you have tested connections and fuses, but, did you actually use a meter or test light? Do you actually have power at the pump? If not, chase it back with the meter or test light to see where you are loosing the power.

phattboy
 
It sounds like you've tried everything that I know. I know GM's fuel systems suck in just about every thing they make.
 
On a G.M. vehicle the fuel pump should run for three seconds when you turn your ignition on. The fuel pump runs all the time when the engine is running. Fuel pressure is regulated by a fuel pump regulator, vacuum operated , it is under the hood inline in the fuel system. Pull the vacuum hose off, if there's evidence of fuel in the vacuum line, the regulator is bad. You can jumper the relay Pins 30 and 87. The pump should run continuously.With the key on. If not, check for power AND ground at the sending unit connector.If you have neither start working back up the wiring loom. If you have both at the tank , yes, it could be a bad sending unit or a bad pump. On all G.M. vehicles it is better to install a dealer complete fuel pump module assy. Nip it in the bud and be done with it.
 
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