Engine/Transmission (1998.5 - 2002) more fp mysteries (miseries)

[Cowboy]

I dont know if this is going to lead to a bigger problem, but has anyone seen this ? I bought this truck with a newly installed airdog fuel preporator (pump,filter and air separator) its not driven much since I bought it, still modding it, but I just drove yesterday, and noticed a wild swing in FP from 16 to as low as 7 lbs mostly at idle or coasting is this a problem? if it is any suggestions? the airdog is new, less than 1,000 mi, plumbed into stock system, thru the stock filter and line to IP any ideas would be GREATLY appreciated.

 

[twheat]

Does this happen when you around a 1/4 tank of diesel? What model of Airdog?

 

[magaliasram]

Sounds like a pickup problem is the plumbing from the Air Dog to the tank stock? That is where I would start looking from.

 

[JFringer]

i had a similar problem where on my last truck i cut the draw straw just a bit to short. i had an air dog 150 intalled on it but it only did it during braking with less than 1/2 tank of fuel. not much help there...

 

[Cowboy]

its the airdog 100 with water separator and fuel filter, the fuel pickup is stock, and the problem occurs when tank is full (never been less than 1/2 tank) I just discovered that the installer ran supply line thru the STOCK LIFT PUMP AND FILTER!!! why put a performance pump thru stock problem parts? I hope this is the reason for my pressure swings, now I gotta look at EVERYTHING this guy did, to make sure no more dumb stuff shows up, (the "new" truck suprise search) thanks, guys for the input.

 

[DACoffman]

change filter

Had the same problem with mine yesterday(stock pump)was fluctuating 4lbs idling and would drop to 6 wot. Changed the filter and back to 14 idle and 10 wot.