Fuel Pump continuously running after swap. Help!

[old_betsy]

i had this issue and another member was also which i replied to a few weeks ago. did you try searching before posting? idk who did your harness but you will need to do some tracing and testing and get the schematics for your truck.

http://www.ls1truck.com/forums/showt...580#post518580

Just visited this post. Funny thing is that i just installed a new oil pressure switch with the swap because my old one was starting to go bad(fluctuating reading). Maybe I got a bad one. Would it still be making the fuel pump run even with the relay disconnected?

[kewljay223]

ok well again, you will have to get a meter out and do some testing. since you have the 2 second power from the pcm and its running without the relay, then that leaves everything on the output side of the relay including the pressure switch which is actually in parallel... do you know how to read a wiring diagram? did you integrate the harness yourself or did you buy a premade one? what "plug" did you splice in??? (never heard of that)... is it the hotwire kit or something?? is the walbro external or internal? does the pump run ANYTIME that the battery is hooked up or only after you turn the key and shut it off or???

as you can see there are a lot of factors here that you havnt mentioned that are needed to help diagnose this....

in that link, i explained exactly how the fuel pum circuit works so im not going to type it again. grab the diagram for your truck and follow the path from the battery source throuh the relays, switches and compare to what you did to it.

ill give you a hint on how to narrow it down. haha there are 3 connectors you can disconnect (maybe 4 now that you "spliced" one in...). get the pump running when its not supposed to. disconnect the connector at the tank thats mounted on the framerail. if it stops, that eliminates a problem from that connector to the pump. then try the new one you added since im guessing its around that area and see if it stops. if so then move to the connector under the brake booster. should be flat and gray IIRC and has 4 wires.... if it stops then try the oil pressure switch connector. if you get all the way to that connector then your switch is either bad or its wired wrong or something is wrong around there.

basically what your looking for is a 12v+ which is always on that is not supposed to be. thats all i can help you do. like i said, your going to have to get that tester out and find the source. good luck