Fuel pressure quetion?

TravisG

TravisG

#THEREALLAVONMILLER
Joined
Aug 23, 2006
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I have a FASS 150 serial #2489 on my 2002 2500 4x4 H.O. Recently my electric fuel pressure gauge crapped out and I decided to change to a mechanical Di Pricol gauge(Thanks CamoTanker)

Before the electric gauge was stuck on 17 p.s.i. now with the new elctric gauge it is on 13.5 or so and drops a little on acceleration(no wide open runs but I could get one if needed:evil)

I have Mach 5's a HTT 66/65/14 a Smarty and JVD fueling box. The pump is pretty fresh and the filters have about 5k miles on them. What I am wondering is if maybe the spring needs to be replaced or if maybe the FASS is gettin a little old. I know it is not really the pressure that matters but the volume, but that much of a pressure change seems a little odd to me. Any suggestions.

Thanks in advance for your time Dan.
 
Travis, we can check the pressure again if you want just give me a buzz.
 
TravisG said:
I have a FASS 150 serial #2489 on my 2002 2500 4x4 H.O. Recently my electric fuel pressure gauge crapped out and I decided to change to a mechanical Di Pricol gauge(Thanks CamoTanker)

Before the electric gauge was stuck on 17 p.s.i. now with the new elctric gauge it is on 13.5 or so and drops a little on acceleration(no wide open runs but I could get one if needed:evil)

I have Mach 5's a HTT 66/65/14 a Smarty and JVD fueling box. The pump is pretty fresh and the filters have about 5k miles on them. What I am wondering is if maybe the spring needs to be replaced or if maybe the FASS is gettin a little old. I know it is not really the pressure that matters but the volume, but that much of a pressure change seems a little odd to me. Any suggestions.

Thanks in advance for your time Dan.
Click to expand...

Forgive me here...but i see some conflicting info here....

I’m guessing you meant mechanical right? Do you have an isolator inline or something to that effect? I’m wondering if you need to purge some air out to get the gauge to read correctly. This would be the most common reason for pressure issues we see.

We can get you a spring...but honestly...if the pump is moving return fuel, you should have good pressure.

One other thing i have seen on some of the older FASS systems with the older motors...is the high pressure relief spring in the T-Block can get weak or brake. Its very rare...but considering the issue you are seeing and the age of your system, it might be worth a check. Main thing is to see if you your FASS is returning fuel back to the tank. Because if the high pressure relief gets weak or brakes, it will take over pressure control and not allow the lower return flow regulator to do its job...and it will cut off all return fuel going back to the tank from the FASS.
 
Oops! My bad on the typing error.


Thanks Dan and Rob. I will give ya a call tomorrow and maybe swing by.

I also forgot to thank the guys at Performance Car and Truck in Denver for the install. I am out in Denver workin with limited tools and they were more than happy to help out.
 
I cant count the times that i have installed isolators, took my time, made sure every connection was taped and torqued......and the thing still caused fits....it happens...

Let me know what you guys figure out.......:Cheer:
 
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