Attention: TDR Forum Junkies Well, as some of you remember I was running 25psi when I first got my FASS... changed to a 13psi spring and had a solid 12psi at idle.
Well fast forward about 3k miles... about 1000 miles with the new spring and it was around 10psi... I didn't pay it any mind. Got into Albuquerque and when hitting a hard bump, my low pressure light is flashing on... figure it must be the switch getting jarred. But being anal, I checked... 8psi at idle... now the light doesn't come one even under WOT so... After talking with my father we decide the easiest thing to do is change the filter out thinking it might be plugged? Pressure was the same after the change... the FASS primed the filter within about 5 seconds which leads me to beleave there is nothing wrong with the pump. So... what did I change... THE SPRING! I contact my dealer who calls DDP... they tell him that a spring won't settle that fast... I'm like yeah, it can. DDP tells him I have a restriction somewhere... well, there is only one place that can happen since the gauge is by the CP3 and the low pressure light is on the FASS, if it is restricted it is from the FASS to the tank (or internal)... my dad is thinking either a non-tempered spring or a broken spring is the cause.
So, now that I have studied things a little more... the pressure is pulsing at the CP3... the gauge is bouncing from around 7 to 9psi. You can also hear this pulsing in the fuel being returned to the tank (taking the filler cap off)... and there is A LOT of fuel being returned to the tank. The pump is smooth (so it isn't causing the pulsation as far as I can tell) and I am getting a little bit of cavitation which I attribute to the increased flow due to the drop in pressure.
So, anyway, the FASS dealer (Long Island Performance Diesel) orders me several springs to see if that is the issue... my dad is pretty confident it is a spring (and so am I).
So, guess I'll let everyone know what happens with a new spring... I put about 500 miles on the new one and then figured that it was all right... then gave the other one away!!! Dumb luck! At least I still have the factory system to fall back on if I need too.
Oh, and I'm down to around 7psi when it is warm now!
steved
Well fast forward about 3k miles... about 1000 miles with the new spring and it was around 10psi... I didn't pay it any mind. Got into Albuquerque and when hitting a hard bump, my low pressure light is flashing on... figure it must be the switch getting jarred. But being anal, I checked... 8psi at idle... now the light doesn't come one even under WOT so... After talking with my father we decide the easiest thing to do is change the filter out thinking it might be plugged? Pressure was the same after the change... the FASS primed the filter within about 5 seconds which leads me to beleave there is nothing wrong with the pump. So... what did I change... THE SPRING! I contact my dealer who calls DDP... they tell him that a spring won't settle that fast... I'm like yeah, it can. DDP tells him I have a restriction somewhere... well, there is only one place that can happen since the gauge is by the CP3 and the low pressure light is on the FASS, if it is restricted it is from the FASS to the tank (or internal)... my dad is thinking either a non-tempered spring or a broken spring is the cause.
So, now that I have studied things a little more... the pressure is pulsing at the CP3... the gauge is bouncing from around 7 to 9psi. You can also hear this pulsing in the fuel being returned to the tank (taking the filler cap off)... and there is A LOT of fuel being returned to the tank. The pump is smooth (so it isn't causing the pulsation as far as I can tell) and I am getting a little bit of cavitation which I attribute to the increased flow due to the drop in pressure.
So, anyway, the FASS dealer (Long Island Performance Diesel) orders me several springs to see if that is the issue... my dad is pretty confident it is a spring (and so am I).
So, guess I'll let everyone know what happens with a new spring... I put about 500 miles on the new one and then figured that it was all right... then gave the other one away!!! Dumb luck! At least I still have the factory system to fall back on if I need too.
Oh, and I'm down to around 7psi when it is warm now!
steved
