I have 97 12 valve and seems like im not getting the fuel i should be. Spec says 15 psi idle and 25-30 psi 2500 rpms no load. I checked my pressure and it was higher than 30 psi at idle. It seems to me i might have a restriction causing higher pressure but low flow. Im not sure. I was just wondering if any has seen this and if any input yall might have could help me. Thanks

 

when was the last filter change?

is you psi tap before or after the filter?

 

The filter was changed about a month ago and im testing the pressure right at the injection pump.

 

Sounds like a gauge issue to me.

Most ALL 12v's need some kind of snubber placed into the fuel pressure line if your trying to read pressure on the mechanical lift pump.The only way you would not need to snubber is if your using a electric fuel system and its at a constantly set pressure.....Andy

 

How do you this setup? Need some specifics here. What size line?, where are you measuring fuel pressure? Do you have a needle valve or pressure snubber?

 

its has banjo bolt wth quick coupler. Its 3/8 line with gauge. Its is on the bolt of the injection pump. When you rev the engine with no load the pressure goes down. Sounds like junk lift pump. Is ther two differnt types of lift pumps for these motors?

 

You need to have a needle valve of pressure snubber in there - the pressure spikes from the pump will quickly damage most guages.

Reving the engine as well as pressure at idle isnt that important - need the pressure at cruise and at WOT.

Should be only 1 lift pump - piston type. About $80 or so at Cummins.