87 CHEVY BLAZER, FUEL PUMP NOT GETTING POWER

with replacing all those components did you test and check how far your power goes --need to check and test components [new doesnt mean free from defects ] and also test fuses ,fuse, panel, harness and connections

Need to connect a fuel pressure gauge and see if you are getting sufficient pressure to the tbi

the one with dim power is the gas gauge,the other power wire(think it's gray) will only have power for about 3 seconds after key is switched on.
have to have an assistant turn the key while you check for power.

you should have the fuel pressure tested to make sure there isn`t a problem with the fuel pump after it has been running awhile as sometimes a pump will slow down or quit when it gets hot or the volume drops off even with good fuel pressure so both need to be checked at the same time.

there are many things that can cause this, fuel pump or filter, fueses, or even your key. your key has a transponder in it that lets the blazer know you have the right key and not just some screw driver. if you have too much stuff on your key chain it will interefere with this, or if you had to have new keys made. check with your local chevy dealer if you have a concern of this or need to prgram a new key

Check for 12 volts power at the fuel pump harness. If no power is going to the pump, check the fuel pump relay. Also, check the fuel pump inertia switch. Ford usually has it on either inside left or right rear trunk fenders.

If the crankshaft sensor is bad, ECM will give no voltage to the pump. It is design to stop the pump running in a case the engine stop during an accident. Check it out. Good luck.

check the ecm fuse and also for power to the ignition and fuel relays.Don't forget about the bump switch which shuts of the fuel etc when the truck has hit something or recieved an impact.

check the fuses called 'ECM 1&2 or A&B'. one of them blown can cause no fuel/no spark both.

Check for dead battery. Test wipers, radio, headlights and heater fan. If all work normally, battery is probably charged and you may have bad starter or alternator ....

Good luck...