Lift Pump question
 

Ok, i am sure this question has been asked before, and i apologize i am new to the diesel life. So i just picked up a 95 Chevy K2500 with the 6.5TD engine code S. The guy before me pulled the fuel pump relay out and wired it with a switch on the dash. My question is, if i flip that switch and run the lift pump constantly while driving the truck, will it do anything to the truck as far as hurt anything, or is that ok to run it like that? I am not sure why he did this, i am being told he had prime issues with it, however i have not left the switch on all the time when i drive it. I usually start it up, then flip the switch on, once i take off i wait a min or 2, then flip the switch off. I leave it off unless it does a little miss jerk feel then i will flip it back on, it usually only does that if i am in the peddle hard, or if i am towing something. For some reasons when i first take of with it after sitting for some time, even with the switch on, it will do that little miss jerk feeling, but i just lighten up on the peddle till it smooths out. I did leave the wires in the socket for the relay and pushed the relay in with hard wired to the switch to see if i even needed to have the switch and it runs the same as it did without the relay plugged in. Thanks in advance for any help with this issue. i just dont want to break the truck or anything, want to make it right and reliable. I always worry the switch will stop working or wire will come off and break down somewhere.

You need the lift pump for the engine to operate and the switch to the lift pump is a bad idea not to mention very dangerous you should not drive the truck until you fix this you are put your life and others around you at risk, you need to fix this immediately.

As I said, I am totally new to the diesel world. Can you tell me how to diagnose the problem or things to check to see why it is he wired the switch to the relay socket under Hood? I don't even know what to check or why it wouldn't work right. Any help would ad greatly appreciated.

My guess is he didn't have a clue what he was doing but the OPS ( oil pressure switch) works in conjunction with the LP ( lift pump) relay what you will probably want to do is get a new AC/Delco OPS don't go to a parts store because these are junk and you will only save a couple bucks and have a inferior part put this in it's located at the back on top of the engine where a distributor would be on a gas burner Chevy install that and hook up the relay like its supposed to be and let us know what it's doing from there, you can more than likey have the OPS from the dealer same or next day for around $30 please don't use a parts house brand these are junk right out of the box.

OK. Thanks for the help, I will call dealer tomorrow and get one and get it switched and let you know. Thanks again.