W900 Cat C15 SDP Fuel Filter Gauge Question

Was the fuel filter changed?

 

Was it reading that high before the filter change? Do you have a fuel pressure gauge?


Can someone tell me how that gauge works or where its plumbed in? I know its a restriction measurement but I've never understood from where. Everything after the pump has positive pressure and obviously the draw side has negative pressure but not sure how that would be affected by filters.... my truck has that gauge but it has never worked and its in the dumbest spot behind the steering column

 

If that's correct you're going to be Dead in the water soon. I've gelled up before and the truck sputters a bit past 15 INHG and completely shut down somewhere around 20. it should run around 2 at idle and 4-5 at full throttle. You need to confirm that all fuel filters are new if you didn't put them on yourself.

Assuming the sensor is reading correctly (if the gauge is steady it probably is) there's a # of different reasons that your fuel system is building excess vacuum.

-Algae in the tanks is causing filters to prematurely clog

-You got a bad load of diesel that prematurely clogged the filters

-The fuel lines are swelling or collapsing (unlikely given the age of your truck)

-A tank vent line is clogged

I had a bit of an oddball situation myself recently where My vacuum was getting up to 8 on a heavy pull in cold temps. I suspected a build up of paraffin wax in my fuel system to be causing this as this had gradually gotten worse for years and showed itself as a problem primarily in cold temps so I dumped a bottle of 911 in each tank and topped them off with #1 and the numbers are back to normal now so that's another possibility.

 

Start with a fresh set of filters and go from there. A tank of crappy fuel doesn't care how new the filters are.

 

You do you. I'm just suggesting the easiest starting point.