FASS installed are these the readings I should see?

[Doughboy21kd]

I installed my FASS yesterday and took out for test drive today and at first when ever i came to a stop or was slowing my pressure would flucuate up and down from 15psi down to almost 3psi..... I figured it probably had something to do with the fact that the truck was almost out of fuel... . Once i filled it up it hasn't done it since... .



Now with the FASS i am running these pressures... . Are these normal for my setup with whats in my sig?



Idle: almost 15psi

Cruise: ranges from 13. 5 to 15

WOT: have a hard time getting it to 11 or so maybe 12



by the way i am running a FASS 95 with the filter kit

 

[steved]

I installed my FASS yesterday and took out for test drive today and at first when ever i came to a stop or was slowing my pressure would flucuate up and down from 15psi down to almost 3psi..... I figured it probably had something to do with the fact that the truck was almost out of fuel... . Once i filled it up it hasn't done it since... .



Now with the FASS i am running these pressures... . Are these normal for my setup with whats in my sig?



Idle: almost 15psi

Cruise: ranges from 13. 5 to 15

WOT: have a hard time getting it to 11 or so maybe 12



by the way i am running a FASS 95 with the filter kit

Pressures sound normal to me...



The flucuating readings were most likely from the FASS cavitating. How low on fuel were you?



steved

 

[Doughboy21kd]

i was on "E" almost... ... . I probably had about 5 gallons in it..... But like i said it only did it when i would come to a stop or slow down... So i'm guessin that the fuel would flow to front of the tank and it would leave nothing for the FASS to suck... ... Hasn't done it yet since its been a full tank of fuel... .



As far as PSi's go i am actually up from yesterday now... ... most i could get yesterday was about 15 now i am getting about 17-18 and have a hard time sucking the pressure down to 15... Maybe pump needed to be broke in... . Oh well

 

[steved]

i was on "E" almost... ... . I probably had about 5 gallons in it..... But like i said it only did it when i would come to a stop or slow down... So i'm guessin that the fuel would flow to front of the tank and it would leave nothing for the FASS to suck... ... Hasn't done it yet since its been a full tank of fuel... .



As far as PSi's go i am actually up from yesterday now... ... most i could get yesterday was about 15 now i am getting about 17-18 and have a hard time sucking the pressure down to 15... Maybe pump needed to be broke in... . Oh well

I actually sucked air with the OE pump in my 99 once... had a 1/8 tank and had just went down a steep hill. Caused it to buck for a few minutes.



My FASS did the same thing with the pressures... almost like the pressure return ball hadn't quite seated. Also, temperatures (cold/hot) will cause the FASS to change pressures... I am pretty sure this is related to fuel viscosity.



steved

 

[Doughboy21kd]

Another question i have is: Am i going to have the same pressure all the time or is it gonna flucuate up and down due to weather, temp, etc, etc, etc..... I am guessing that i will have a different pressure daily due to certain conditions..... I am guessing that pressures could even change from starting the truck in one spot and then starting it in another?



Please let me know... ... ... I seemed to always have the same consistant pressure with the stock pump and now with the FASS on it jumps all over up then down... .

 

[steved]

I would expect to see fluctuation day-to-day because of temperature and fuel variation, but not driving down the road at a steady speed or sitting at an idle (unless the pump is sucking air or cavitating)...



I would start by checking the guage if you have not done so already, then check for an air leak somewhere...



steved

 

[LowFly]

Pressure is normal. Should be fine for your truck.



You cant run 5 gallons in the tank with that draw tube as you found out. Just put fuel in it when the light comes on and you should be ok.



My pressure runs about 14 PSI all the time. This morn it was 13 PSI... . but it was 6* out. Thicker fuel, pump has to work a little harder.



As for the pressure increase... ... that is a little strange..... might have been some air that needed to be pruged in the diesel side of the gauge... . when you shut the truck off, it back flushed the air into the pressure line and "Bleed" the gauge. Just tossing a guess here.....