scrappy2686

ok so i changed out the fuel pump on my blazer because it was maiking a horrible grinding noise. now after teh new pump is installed i have worse fuel pressure now than i did before. any suggestions? could it be crossed hoses or just me being an idiot and screwing something up somewhere.

EinST

Welcome to the forum. What's "worse fuel pressure," and what was it before? What year Blazer are we talking about, BTW?

maxxman04

did you change fuel filter? what year, what motor? yes, it makes a difference.

scrappy2686

sorry i forgot to put the year and motor. its a 97 with a 4. vortec. i changed the fuel filter, fuel pump, and the fuel pressure regulator. before all the new parts were installed i had probably 30-40psi which was still too low because i could start the truck using ether and then it would run on its own but sh***y now i am only getting maybe 10-15 psi. could i have crossed a wire somewhere when installing the new pump connector.

EinST

Or, the fuel pump is not getting the full battery voltage.

scrappy2686

possible but i dont know im running out of ideas for this truck. maybe crank or cam position sensor. it turns over all day long i may swap the two black wires around just in case i may have crossed them just to see what happens.

EinST

Those sensors have nothing to do with the fuel pressure. Do you have low fuel pressure or not and what "two black wires" are you referring to?

scrappy2686

i do have low fuel pressure. there are four wires on the harness, black, grey, purple, and a small 18g black wire. the four wires on the new harness are black/white, grey, purple, and black

EinST

Would the pin-out of the electrical connector at the fuel pump help?

Terminal A battery voltage to fuel pump
Terminal B fuel level sensor voltage
Terminal C ground to fuel pump
Terminal D fuel level sensor ground

in2pro

Are you able to smell any fuel? if you can smell it, its leaking somewhere...
Its possible to have the pump running backwards and that could lead to the poor fuel pressure...