Replaced Hummer fuel lines and lift pump

I was changing the fuel filter on my Hummer and found it and the Fuel Filter Manager to be extremely dirty. While I was taking it all apart I decided to also replace the lift pump. I then realized that I really should have a full time fuel pressure gauge, as the 1996 Hummer didn’t come with one.

Fuel pressure gauge attached to the Schrader valve.

There was a brass fitting with a fuel pressure port on the fuel line between the fuel filter manager and the injection pump. I learned that that part should instead be on the drain line rather than between the FFM and IP. That fitting looked to be about 3/16” so it probably was a bottleneck in the fuel line.

I replaced the old brass fuel pressure test port (3/16”) with an anodized aluminum one made by Evil Energy (5/16”). The Schrader port came from Riffraff Diesel.

I removed the Schrader fuel pressure test port from the brass T and replaced it with an industrial 5V pressure transducer. I will be attaching that to an Arduino microcontroller which will share fuel pressure readings over Wifi with my truckputer. This will provide me a live fuel pressure reading. That information also gets logged to a Postgres database on the Raspberry Pi.

Thanks to the diesel experts on The Truck Stop and Hummer Network forums who patiently answered my numerous questions. You know who you are.