Quick Answer

Quick Answer: What is injector return line?

With a return line the fuel pump can provide pressure to the injectors without changing the pressure in the fuel tank. In either case, fuel is departing the tank for good at whatever rate the engine is burning it. Also, liquid gasoline will turn into a vapor, which should offset the negative pressure.

What is a diesel return line?

By removing the return box, you reduce the fuel temperature to prevent it from evaporating or vaporizing outdoors or when it is parked inside a warm environment. A fuel return line goes back to the tank of gas after collecting fuel. A high-pressure supply for the fuel injectors is necessary for fuel injection systems.

How do you bleed fuel lines on a 12v Cummins?

How to Bleed Your Cummins Fuel System

Why did Cummins stop making the 12-valve?

By 1998, emissions regulations necessitated the switch from the 6BT “12-valve Cummins” to the ISB “24-valve Cummins”. Although the 24-valve was more powerful than the 6BT and was, by all means, still a very good engine, it never achieved quite the same popularity as the original 12-valve.

Is a return fuel line necessary?

You don’t need it with a mechanical pump. Mechanical pumps supply fuel based on RPM, and so long as you’re not running a big hipo mechanical pump, you’re fine without a return. Edit: Keep in mind that the pump doesn’t create pressure, resistance to flow does.

Why do diesels have fuel return lines?

It is used as a lube in a diesel engine, and does not get burned in the chamber. This leftover oil is sent back to the tank.

Does a fuel return line have pressure?

A free flowing return line maintains consistent pressure in the system. Ending the return above the fuel level in the tank, or in the filler neck will cause aeration. This can lead to fuel starvation and pump wear.

What are the symptoms of a clogged fuel return line?

Carburetor flooding, engine stalling, and hard starting

If the fuel return hose becomes blocked or kinked it may cause the carburetor to flood from excessive fuel or pressure buildup. A flooded carburetor may cause engine stalling and hard starting until it is cleared, or enough fuel has evaporated.

How do I know if my diesel injector is stuck open?


  1. Trouble starting the vehicle or uneven idling. The engine cranks but doesn’t start unless you crank it for a long time.
  2. Misfire.
  3. Smell of fuel.
  4. Dirty emissions.
  5. Increased fuel consumption and poor miles per gallon.

How do you get air out of a Cummins fuel system?

The Cummins manual says to cycle the ignition key(but don’t start the engine) several times between run and off. You should be able to hear the lift pump running and then stop. Leave it in the on position for 30 seconds or so.

How do you prime a fuel system on a 5.9 Cummins?

How to Prime a Cummins 5.9 Injector Pump

  1. Get into the driver’s seat of the vehicle.
  2. Turn the key to the “On” position and listen for the mechanical pump in the fuel tank to engage.
  3. Turn the key enough to engage the starter.
  4. Repeat Step 3 four to five times to allow the fuel line to pressurize.

How do you get rid of an airlock in a diesel engine?

How Do You Get Rid Of An Airlock In A Diesel Engine? A fuel lift pump and a fuel filter are connected in the engine. The lever or plunger will need to be tapped while a look is made at the bleed screw on the top. The system will produce bubbles as it loses air.

How much HP can a stock 12v Cummins handle?

The forged-steel connecting rods found in the 12-valve 5.9L (and ‘98.5-’02 24-valve engines) are of an I-beam design and capable of easily handling 800 rwhp in stock form.

Which year 12 valve Cummins is best?

1996-1998 has the best injection pumps (perhaps ignoring the 1989-1993 VE) and stronger automatics compared to earlier years. Look at the buyers guide section in the thread below. The 1998 12 valve trucks were only built in 1997.

What is a 12 valve Cummins worth?

A shop skilled in Cummins swaps will charge around $12,000 to $15,000 to take a 12-valve version with the 5R110.

What size should my fuel return line be?

Active Member. Return line should always be the same size, if not 1 size larger than your feed line.

How much pressure is in a diesel return line?

You don’t need the check valve but the pressure where the injector return line connects back into the system needs to at lift pump output pressure, about 18-35 psi.

How much pressure is in a diesel fuel line?

Both GDI and CRD systems use a high-pressure pump, but the pressures are very different—3000 psi for GDI and up to 28,000 psi for a CRD system.

What is fuel return system?

A return-type fuel system is one that is designed with a fuel pressure regulator that diverges the fuel pressure based on the power of vacuum suction from the engine’s intake system.

Can you block off fuel return line?

Any fuel going through the return line is simply fuel your engine did not need/could not use. Blocking or restricting the line only increases fuel pressure at the injectors. Blocking the line results in the fuel pressure just being the maximum the pump can push.

How do you fix code P0087?

What repairs can fix the P0087 code?

  1. Replacing the fuel filter or screen.
  2. Replacing kinked fuel lines.
  3. Removing and replacing the fuel pump.
  4. Replacing a faulty fuel pressure sensor.

Will air in the fuel line symptoms?

Fuel lines that are submerged in air may stall, hiccup, or refuse to start. Air bubbles in fuel lines can cause these symptoms. Keep your fuel lines free of air for maximum performance.

How do you free up a stuck injector?

Turn the injector clockwise and counterclockwise, if possible, to disperse the lubricant. If the injector wont turn, then wiggle it in a circular, oscillating motion to cause the O-ring to “breathe” the lubricant in and out.

What happens when a fuel injector is stuck open?

With stuck open fuel injectors, the cylinder in the combustion process will be deprived of the much-needed fuel. If you drive, the engine will have to operate and complete cycles without adequate fuel to burn.

What are the symptoms of a stuck fuel injector?

Dirty Fuel Injector Symptoms

  • The Engine Misfires. Dirty fuel injectors may cause your vehicle’s engine to misfire.
  • Idling Gets Rough. Does your vehicle sputter and shake when you’re at a stop sign or sitting in traffic?
  • Your Gas Mileage Tanks.
  • The RPM Needle Starts to Dance.
  • Your Car Won’t Start.