It's funny how phone calls from customers can remind me of other topics I have thought about writing an article on, but never got around to. Don't worry, this one is pretty short.EVER SINCE I INSTALLED YOUR FUEL SYSTEM...
My Truck Won't Start
My Truck Lacks Power
My Truck Smokes More
...various others...
These are just a few of the types of calls we get, particularly after someone has installed one of our Regulated Return kits. The very first question I ask is, "What is your fuel pressure?". The answer to this question tells me if the fuel system seems to be working properly. Clearly if the customer has 0psi of fuel pressure, they need to check over their installation and see where they went wrong. Or maybe they need to check to make sure that the pump is running. They need to review the instructions and retrace their steps and make sure everything is installed as directed. Sometimes we have to spend significant time helping them figure out the situation, hence the other fuel system diagnostic articles I'm working on.
On the other hand, if they have correct fuel pressure, 99% of the time they have another issue. It is natural to assume that the most recent part you installed is what caused your problem (whatever that may be), but what most customers don't realize is that the fuel system they have installed in their Powerstroke is just a "delivery" mechanism, its sole purpose is to place fuel into the fuel rail at a particular pressure, nothing else. In both 7.3L and 6.0L applications, the trucks computer has no clue (nor does it care) if there is fuel actually in the rails. If they have pressure on the gauge at the regulator, there is fuel in the rails and the fuel delivery system is working...they need to look elsewhere for their problem (particularly a no-start or smoke concern). Sometimes the customer doesn't realize that they unplugged something while working on the fuel system, and the truck won't run until they plug it back in (the IPR is a good example). Sometimes they need to trace their steps and make sure they didn't forget to reinstall something, tighten something, reconnect something. Sometimes there are other components in the truck that are not working properly (like a fuel injector, high pressure oil pump or turbo) that are the actual cause of their issues. Most of the time the problem turns out to be something simple and silly, the kind of thing I imagine many of our customers quietly kicking themselves over.
Lacks Power Exception: The one caveat here is the "lacks power" situation. I'm a big proponent of in-cab fuel pressure gauges on any truck with a modified fuel system (especially larger injectors), because it is the ONLY way you know what is happening while driving. If a customer has significantly larger injectors, they could be reporting a lack of power due to fuel pressure dropping off under heavy throttle. This would happen if they don't have enough fuel pump to support their chosen injector size. An in-cab fuel pressure gauge is the answer, as it will tell the driver if the fuel system is able to keep up. If the fuel pressure is holding under heavy throttle, but the power is dropping off, the fuel system is not the problem...time to start looking at other power related systems.
So before you assume that whatever problem your truck is having is caused by your recently installed fuel system, check the fuel pressure. Correct and consistent pressure means you have adequate fuel in the rail and the delivery system is doing its job. Diagnose from there.
Author: Dennis Schroeder - Co-Owner of Strictly Diesel
Dennis has been Designing, Building and Supporting Aftermarket Fuel Systems for 7.3L and 6.0L Powerstrokes since 2001.