I just installed a brand new LP and an Isspro FP gauge. I need some numbers to compare mine with. ??? Do your readings fluctuate at all or are you always seeing a solid number? How many lbs. does it drop when you are at WOT. What are you getting when cruising? Any info would be greatly appreciated. ;D

 

With my stock LP, I was seeing 13 at idle and 6 at WOT. > That was the replacement for my first one (8psi at idle and 0 at WOT). Now I'm seeing 18 at idle and 14 at WOT. ;D

 

Stock lift pump (1st replacement) with Isspro Mechanical Gauge.

Idle-15 psi, 60MPH Cruise-13psi, WOT-11psi.

Readings taken post-filter

 

My second pump Idle 14#--cruise empty 11# cruise loaded as low as you dare to run :'(

 

My replacement runs 15psi idle, 11-13 cruise and 10 wot

 

Yes, the mechanical ISSPRO FP guage will fluctuate a little with the pulses of the lift pump. Your truck should run around 15 psi at idle, 8 - 12 at cruise, and somewhere around 5 or 6 at WOT. If you go to the 3rd gen at some point, be advised that the common rail changes that were made change that. The new gen system runs at lower lift pump pressures, but give a little more fuel volume to the injection pump, which runs a bit higher pressure than the 2nd gen HO's.

 

15 at idle- 12 cruiseing - 8-9 wot ;D

 

Gentlemen -<br><br>Good topic..I too replaced my stock LP, and installed a guage..Was wondering the same thing..I now have 15 idle, 13 at 70mph, and 10-11 wot..guess it works ok then..

 

[quote author=GrandpasRam link=board=4;threadid=14449;start=0#135747 date=1052314204]<br>Your truck should run around 15 psi at idle, 8 - 12 at cruise, and somewhere around 5 or 6 at WOT. <br>[/quote]<br><br>According to Cummins, anything below 8 psi warrants a replacement.

 

With my stock lift pump, I cannot get the pressure down to ten. <br>Are my injectors too SMALL? !!!! Ha HA.

 

GrandpasRam,
If you use a simple $4.00 needle valve with the mechanical gauge, you won't have the fluctuations in the needle.
Just close the valve all the way, the open it a tiny bit at a time until the gauge shows a reading.
It elimintes the pulses.

 

I see 18 at 70 and 4 wot

 

Mine was 12 at idle, 9 at 70 and 6 at WOT. Just replaced the lift pump last week and added genos banjos. Now I'm seeing 13 at idle, 11 at 70 and 10 at WOT. The gauge fluctuates *a lot* less with the banjos, I guess because there's less drop in pressure through the line.<br>Bruce

 

Question 1: Are all of your readings PRE or POST filter?<br><br>Question 2: Switchboard, did you see an increase in MPG when you installed your new LP and banjos?<br><br>I'm just wondering because I have a LP and Banjos waiting to be installed due to troubleshooting a 15-16 MPG issue driving at an average speed of 65 MPH on the highway with no load.<br><br>Before I put these on I'm going to hook up a FP guage I recently installed to get an indication of what everything looks like now post filter. I was told these electronic guages aren't extremely accurate, they are simply for an indication of what you have.<br><br>I had it checked with a regular pressure guage (not electronic) before any mods and I'm:<br><br>Idle: 11<br>WOT: 9<br>Load: 5-6<br>

 

14.5 at idle<br>12 at cruise<br>0 at WOT &lt;------ Don't do this.