another 6NZ fuel preasure ??

My pressure usually runs between 88 to 98 pounds. I was just driving down the road and the pressure jumped to 120 to 130 pounds. It happened last week and lasted for a few minutes. It happened again last night and lasted for an hour. Then went back to normal.

The transfer pump was replaced a year ago and has the updated spring kit in it. The hand primer pump is a few months old. The splitter valve is also a few months old.

I also had the return line off from the filter head a few days ago, (to fill a bucket with fuel) the return flow seems to be at a good volume.

The first time it happened, was right before I changed both fuel filters. Last night was on new filters with eight hundred miles on them.

Fuel restriction was normal, both times. There was no change in how the truck ran (but I only had 25000# both times)

I have never changed any fuel lines. The truck is a 2003 pete 379 with 6NZ View attachment 48465

 

I thought about the gauge, It has a TelTek electric gauge, they are very accurate and durable. but, you are right could still be the gauge.

 

Help me understand the check valves. If I understand the fuel system on a 6NZ, the transfer pump has a spring/check valve and the filter housing has two sets of spring/check valves. On the filter housing one check valve is on the right hand side near the fuel return (this valve has the hex head that you access from underneath). The other check valve on the filter housing is located on the left side of housing and the hex head is facing me.
Now tell me if I understand this right and explain exactly what the two valves on the filter housing do.

Mr. Haney which of the three valves are you referring to?

 

I think gauges are like oil samples. They make you worry about every thing out of the norm. My wife says I like to worry.