fuel pump not working

[pomai]

Removed the battery for charging, reinstalled the battery, no fuel pressure, fuel pump not turning on. buy past the relay, send power directly to the fuel pump harness, wire has power, fuel pump will not work.
( I noticed that the fuel gauge needle is all the way to the right, at about the 5 o'clock position, when I turn the key on it moves to about the 4 o'clock position and stays there, 10 gallons of fuel)

Installed new fuel pump, same as above.

new gas tank, sending unit, fuel pump.

any ideas please?

 

[1-ton]

What is the year, make, and model of this vehicle?

 

[pomai]

What is the year, make, and model of this vehicle?

1988 K5 Chevy Blazer

 

[1-ton]

When you installed the new fuel tank and sending unit, did you make sure you connected the sending unit ground wire?

 

[pomai]

When you installed the new fuel tank and sending unit, did you make sure you connected the steel braided sending unit ground wire strap?

yes, the black wire to the frame. started this engine about 6 months ago, without any issues, hasn't been out of the garage yet, start it up about 2 to 3 times a week. removing the battery about every 2 weeks to charge, this time when I re installed the battery the fuel pump didn't turn on, and the fuel gauge needle was pinned all the way to the right but moves to about the 4 o'clock position when the key is turned on. I replace the new fuel pump with another new pump, and still nothing and the fuel gauge needle still doing the same thing. I was thinking of replacing the sending unit as well.

 

[1-ton]

do you hear the relay clicking when you turn the key to the ON position? does the hot wire to the relay feel hot...like a hot wire got grounded somewhere. The fuel gauge going to the full position sounds like a power wire got grounded somehow: or maybe the fuel pump fell off the sending unit, and is laid up against the sending unit float. Just throwing out some guesses here.

 

[rampage]

Pump not working and gauge pegged sure sounds like no ground to the tank. Humor me and clean a small piece of the frame to bare metal and a small piece on the tank to bare metal. Then take a piece of wire and connect to those two spots. Bet the 5 mins invested cures both problems.

 

[SpeedlabDan]

Make sure the battery ground is good to the frame as well. Seems like a ground issue to me as well

 

[diesel4me]

I'd also check the wire that sends power back to the fuel pump for its ability to handle AMPS...using a test light or volt meter puts practically no load on the wire,and can show its getting 12 volts,but not with enough amps behind it to actually run the pump--or let it run a short time,then stop..

My friend replaces a lot of in tank pumps at his shop,and most GM ones now come with a new harness plug for the sending unit/pump power wire--they are notorious for corroding internally and causing intermittent problems...you are supposed to replace the oem plug and install the new one or the warranty will be voided..

He learned the hard way using a test light (especially the LED ones that draw practically no amps) is not a reliable test,nor is a volt meter..
One day I showed up at his shop after he had installed a new pump in a GM pickup,and it was towed back in a few hours later,with "no fuel pump" symptoms again...(and he had replaced the plug on the power wire)...he said "I saw my test light light up--but I left it connected and on,for a few minutes,and it started flickering,then it went out"..

I said "sounds like the wire is corroded all the way back to the fuse box and acting like a big resistor"...
I took an old sealed beam headlamp he had on a shelf and hooked a pair of jumper wires to it from the fuel pump power wire,and grounded the other terminal--turned on the ignition,the headlight glowed brightly for a good 20-30 seconds--then started flickering,dimming down,and we stood there and watched the filament in it just glow dull orange for a few seconds--then it went out!..I shut the key off,let it sit a minute,turned it back on,it did the same thing again...

My friend decided to trace that wire back to the fuse box,and just cut it off there and spliced in a new length of wire--the headlamp stayed on a good 5 minutes with no flickering or dimming,so we hooked the wire back up to the fuel pump with the new plug supplied with it,and the truck fired right up,and hasn't come back since..

He now uses that headlamp as a test lamp to check the fuel pump power wires..it has enough of a load to make the faulty wiring show up..we slit open the original wire and it was mostly gangrene dust for the first 2 feet back towards the fuse box from the tank!..had only a few strands left that weren't dissolved..the old pump still worked when he hooked it to a battery too,so it may not have been "junk" to begin with!..