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noticing fuel psi dropping to 48 on WOT

2K views 21 replies 5 participants last post by  sbluke55 
#1 ·
I'M noticing that it drops fast in hottest tune, pump run's around 58to 59 psi ,,I back out of it as soon as I see 48,, it is a concern CORRECT??? WHAT IS THE BEST SOLUTION HERE ?? fuel filter was changed with injector's 3,000 miles??? any idea's I have strictly diesels post pump filter system that wont fit into sig now,,LOL THANKS IN ADVANCE
 
#2 ·
How are you using Corey's kit and the post pump kit? Have you done the pre pump kit?
 
#3 ·
sorry BLUKE , it is a pre pump filter kit .. is my pump on it's way out .. or just stiffer spring .. from bob's DIESEL ORING'S kit I used the middle spring ?? I forgot all about that, LOL
 
#4 ·
I hope that is normal because mine has been doing that for two years.
 
#5 ·
I DON'T THINK SO ,, but that's why I'm askin lol ,, THANKS IN ADVANCE
 
#6 ·
I ran 62 psi with my 238/100's it would drop to maybe 59 psi in my highest setting. Anything below 50 can hurt the lifespan of your injectors. Sounds like your pump is weak. You can do a Bosch setup or just dual superduty pumps you find laying around.
 
#7 ·
Start off by verifying that you don't have a gauge issue first. Just toss a mechanical gauge on and see what your pressures are. Then if you find the pressures are right I would rebuild the fpr. Bob has them for $70.
 
#8 ·
yes I did that last year with BOB'S kit ,with three springs . and I lost the stiffest one.. LOL ,, I wont be able to see the gauge ,so I just watch idle psi. and compare?? THANKS GUYS
 
#9 ·
#10 ·
YES sbluke I did both at same time ,, last year but lost the stiffest spring ,so had to go with the middle spring ,,,, LOL
 
#11 ·
About the only thing left is the fuel pump. Amazon has them for under $100
 
#12 ·
is there a wright up on dual superduty fuel pumps or pics of material's , a kit or somthin just so I'm not running in the dark with this ,, and thanks for the responses
 
#13 · (Edited)
should I get oem or something else ??? and would two of mine in loop be better or 1 6.7 pump/?? witch is better?? IIRC 6.7 pump more volume???
 
#14 ·
Like it has been said before you most likely have a weak fuel pump... But the thing to remember here is its not just the "pressure" that's a main factor of keeping fuel in the heads.. Increasing your fuel flow is also what your after, a better way to explain it is that the air dog system I have on my truck is a 150gph lift pump and I remember correctly it operates somewhere between 7-10 psi which is force feeding my stock high pressure pump which obviously bumps up the pressure to 60 psi ... But as stated before anything below 50 psi at WOT and you'll most likely be running your injectors dry = " If you French fry when your supposed to pizza... YOUR GONNA HAVE A BAD TIME " - South Park
 
#15 ·
And btw my fuel system keeps my swamps 300cc/400% sticks happy as a bug in a rug
 
#16 ·
You have an Air Dog plumbed inline before the factory pump?
 
#18 ·
Could I just do the Driven Diesel pre pump/filter kit, and plumb a 100 gph pump in if my stock fuel pump won't supply enough fuel when I get bigger injectors?
 
#19 ·
I have also seen where people have used a 6.4 fuel pump to supply the factory pump and have had good results.
 
#20 ·
It wouldn't work. Not big enough fuel lines.

The 6.7 pump would be better to use.

What size injectors do you plan on using.
 
#21 ·
Either 180/100s or 175/80s
 
#22 ·
Just do a pre pump kit. A quad feed or frx and you should keep up. If not just replace the pump with an oem one.
If you go to a 6.7 pump or a 100gpm pump you need 1/2" lines.
 
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