The 5.9 Cummins is a nearly indestructible engine with one Achilles heel – the fuel system. Having a fuel pressure gauge is incredibly important to ensure proper operation and avoid costly repairs. When installing a fuel pressure gauge on a 1998 through 2004 Cummins there are some special precautions necessary to protect the sender from pressure spike in the system.
The 5.9L Cummins found its way into a lot of Rams and is also a popular engine swap into other vehicles.
On this vehicle, there were already gauges up on the pillar, so we are putting the fuel pressure gauge in a column pod. To install this, you unthread the tilt lever and the cover will come off easily with two torx screws on the underside securing it.
We went with an AutoMeter Elite fuel pressure gauge (Part #5661). To keep the wiring tidy, we separated the data output and Pro Control wiring.
We extended the electrical tape far enough down to protect the wires as they went through the column. This is right before they were pulled through.
The column cover gets a hole drilled for the wires and the AutoMeter gauge mount installs right over the existing piece.
Here’s another shot of the wiring.
Always leave yourself enough slack in the wiring so that the gauge can be easily removed from the mount, in case you need to move the gauge to gain access to the steering column or instrument cluster for other services.
Automatic transmission equipped Rams have a nice spot on the firewall where the wiring can be passed through.
There’s enough room under the hood that you can easily get your hand down to help pull the harness to the sender out.
We added protective wire loom to the harness to ensure proper operation down the road. These motors last forever, so we need to make sure the gauge does as well.
Here is where the harness pulls through the firewall. This vehicle came to us with a lot of accessories already installed, but we don’t recommend using the firewall as a grounding point (especially not for gauges).
The sheathing slides over to the end.
The sending unit should be remotely mounted away from the fuel filter housing and an AutoMeter Snubber Fitting (Part #3279) should be used to protect the sending unit. These fuel systems are notorious for causing issues and this is cheap insurance for our sender. A thread compound (not tape) keeps us leak free for the long run on the pipe thread fittings (not used on AN fittings). On the right, we see our sender and snubber. On the left is the -4AN braided line with a -4AN to 1/8″ NPT male to male adapter (included with the AutoMeter Part #3227 line kit).
This is the fuel filter housing where we will measure fuel pressure.
Our fuel filter housing had a 1/8″ NPT hole already installed so the AutoMeter line kit installed easily. In some cases, you may need an adapter or a threaded banjo bolt, like this one.
Here is another shot to see exactly how the line installs.
On the other end, we have a thread adapter to the -4AN line, the snubber and the sending unit. Don’t use the thread compound on an AN fitting as it can actually cause leaks. These are best left alone.
We zip tied everything to the hood release cable to keep it secure and out of the way. We were careful to route the braided line away from any wiring/hoses.
Here you can see the routing from the filter housing to the nicely buttoned up sender.
We wrapped up the data logger and Pro Control wiring under the column. This keeps it out of the way but allows for easy access if we go back to integrate either of these functions.
Always solder and heat shrink your wiring. Scotch lock and butt connectors are not a proper solution for long term durability.
Here’s the Elite 35 psi fuel pressure gauge in place on the column.
Monitor the fuel pressure on your 5.9 and ensure the long life of your Cummins with a fuel pressure gauge from AutoMeter.