Ok guys have an 02 5.9 upgraded raptor lift pump 110 injectors and new vp44. About a week ago I had to replace the starter and ever since my pressure has been screwy. I know I have the pressure to high runs about 28 at idle drop to 17 or so with load. I'm now noticing when I am driving when I slow down, stop, or turn my pressure drops then shoots right back up but fluctuates even at idle what the heck did I do?

 

Does your raptor have an adjustment **** of some sort? you might can dial it back.

 

Is there a check valve in the system that could be doing this. The only thing I unhooked was both positive battery terminals and the starter never was an issue before even with pressure that high. It will shoot all the way to zero then jump back up the fluctuate back and for even at idle now. It will drop to 10.

 

Make sure all the connections are in good shape, grounds and hots. Maybe you jarred a wire loose and you're not getting a good signal.

Do you have a regulator on that pump? Mine is adjustable.

 

Yes there is a regulator on the pump I can adjust I took a video tonight wish it was post able to show what it's doing I just really don't want my vp to burn up again due to pressure.

 

You could see if you can get a mechanical fuel pressure guage from a parts store to temporarily hook up and verify what is actually happening.

Is it possible you bumped the regulator or the jam nut came loose, allowing the regulated pressure to change?