dudeman_85

Ok i have a 1997 k1500 4x4 p/u and its been nothing but problems since i bought it first the fuel pump went so i replaced it and all of a sudden the truck wouldnt start unless i threw some gas in the throttle body then it would run fine after now the fuel pump went again after only a few months warrantied so i replaced now it fires up and stalls right out wont idle or nothing and right before it died when i press the pedal half way down it would go but push it to the floor it would stall it throws codes for throttle postioning sensor map sensor and 02 sensor and im getting 51 psi at the rail i replaced tps sensor and erased codes tps came back so im worried something else is cause the sensor codes so i havent went fourth replacing anymore just yet i have had catylatic converter be suggested as a problem but its newer on the vehicle so not sure dont hear any rattle coming from it any ideas or suggestion to stop me from dumping more unnecessary money into it would be great

maxxman04

ok, first, 51psi is not enough pressure, assuming its a 350 motor. did you replace the fuel filter when you replaced the fuel pump? a clogged filter will in fact wreak havoc on a new pump and prevent motor from running right. replace that first. it's ten bucks. reset codes, run rig again. i'd almost bet it solves your problem. notice i did say almost bet.

shamrock246

what maxxman04 said,the fuel pressure should be 60-66psi

Eddox

Hey, I think it can be the filter also... I had a bad fuel filter once and it did the same stuff your talking about.

Good luck.

dudeman_85

when i replaced the fuel pump the first time i put a new fuel filter in it do u think should need to again i took it off and blew thru it and it didn't seem clogged ive traced to whole fuel system to the rail i didnt know my pressuse was low i was told 50- 60 psi was ok but if its low maybe i need to look back at that and its the vortec v6 not a 350

maxxman04

55psi is absolute minimum for your motor to run close to right. 60 is good. yes, it's only 5psi difference, but that is huge. blowing thru a fuel filter doesn't really tell you much. it just shows if fuel is getting thru or not, but not if the volume of fuel is enough. i'd also check you vent lines from the filler neck to the tank, make sure it isn't collapsed or blocked. a vent system that cant vent will create a negative pressure in the tank, not allowing the pump to work right. this could cause premature pump failure. i'd still try a new filter first, and check the pressure up at the motor. if it's still not above 55psi, then the search continues. good luck.

shamrock246

fuel pressure regulator?,if you have the old style poppet injectors it takes approx 45psi to open them by the time 51 psi gets out to them it might be just enouph to open them but not fully