What is a Returnless fuel system?
A returnless-type fuel system is one that is designed to use the powertrain control module (PCM) to regulate fuel delivery. A fuel pressure sensor mounted to the supply rail of the fuel injectors allows the powertrain control module to keep an eye on the fuel pressure.
Why do you need a return fuel line?
It’s primary purpose is to return excess fuel from the carburetor to the fuel pump, however it serves other important functions as well. Aside from providing a path for excess fuel to return to the tank, the fuel return hose also prevents vapor lock and over pressurization from occurring within the carburetor.
When do I get an error code on my fuel pump?
When the PCM sees voltage below the normal range in the main power circuit of the fuel pump relay, it activates this particular error code. This particular error code, just like other trouble codes, also illuminates the Check Engine light as well.
What does the diagnostic code for fuel system mean?
The descriptors for these codes indicate that there is a lack of switching from the upstream oxygen sensors as indicated by the processor. We begin our analysis by checking to see if the fuel system is working as designed.
What happens when there is no fuel in the fuel pump?
This also verifies that the engine has no fuel pressure. Electric fuel pumps on electronically controlled fuel injection systems need to produce enough “high” pressure to allow the injectors to produce a sufficient spray of atomized fuel into the intake path (or into the combustion chamber in a direct-injection system).
What to do if there is no fuel flow?
If no flow is noted, go to next step. If flow is noted; replace the PLV. Install fuel system tool J-48707 and J-48708. This allows the engine to be isolated from the chassis. Fill the single container with clean fresh fuel and prime the fuel system using the hand primer. Crank the engine for 20 seconds.