john deere fuel pump how to and troubleshooting guide
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John Deere Fuel Pump Troubleshooting Guide

Before resorting to contacting support or repair for troubles with your John Deere fuel pump, it helps to try basic troubleshooting procedures. In some cases, the problem is not as complicated as it looks and only requires simple DIY solutions to resolve. The following are troubleshooting instructions for some commonly-reported John Deere fuel pump problems to guide you through.

How Do I Know My John Deere Fuel Pump is Bad?

A John Deere fuel pump has a sensor that helps regulate fuel flow into the carburetor. If the sensor isn’t working properly, the pump will not give the engine enough fuel to run, causing the engine to backfire and shut off randomly. The process of establishing if the pump is bad and if it needs to be replaced is simple and doesn’t require the use electronic gadgets.

To know if the fuel pump on your John Deere tractor is bad, here is what you need to do:

  1. Drive the tractor onto a flat surface.
  2. If there is not gas in the fuel tank, pour gas into the tank.
  3. Then, slide a pan underneath the engine.
  4. Pop the hood open. Locate the rubber fuel line on the side of the engine and trace it until it goes into the carburetor in the engine. Unplug the pins on the line and the wiring on the line.
  5. Place an alligator clip on the positive (+) part of the battery. Connect the other clip to one of the places where the wires were connected on the fuel line.
  6. Connect the other alligator clip from the negative (-) part of the battery to the other wire connection on the fuel line.
  7. Drain the fuel into the pan. Look at the fuel coming out of the line, if the fuel is pumping out very quickly, the pump is working fine. If the fuel is just trickling out, the pump is bad and needs to be replaced.

How to Clean a John Deere Fuel Pump

Before you start any maintenance, make sure the John Moore is unplugged or turned off. Remove the spark plug lead, and ensure it is secured from coming into contact with the plug.

 Then, follow the steps below to clean:

  1. Remove the fuel cap.
  2. Put the fuel-catching container under the tank.
  3. Unscrew the fuel line nut or hose on the base of the fuel tank.
  4. Once the tank stops draining, use the extraction pump to remove any fuel and sediment settled at the base of the tank. You may need to blow out debris with the air compressor.
  5. Remove your fuel line just before your fuel rail or injection pump. Insert the air compressor nozzle in the hose and blow air back toward the tank to remove any debris in the fuel lines. After blowing out the lines, replace and secure them.
  6. Screw the diesel fuel line nut or hose back onto the base or the tank.
  7. Drain water separator if equipped and replace fuel filters.
  8. Fill up the tank with fresh diesel fuel.
  9. Pour the correct amount of diesel tank cleaner into the tank.
  10. Then, replace the fuel cap and start your machine.
  11. Bleed your fuel system. On some machines, turn your key on and allow the electric fuel pump to flow fuel up to the filters. Crank the engine over until it self-bleeds and starts.

How Do You Test a Fuel Pump?

In order to determine if you need to fix or replace your fuel pump, you need to know the right steps of checking and testing the fuel pump.

Electrical test

  • The first step on this test is to check the pump fuse, since in most cases it is the power that supplies it that fails and not the pump. Locate the fuse box and find the correct fuse matching with the fuel pump. Pull out the fuel pump and check for any signs of failure or if the fuse is blown. If the fuse is okay, then it doesn’t need to be replaced. If so, have someone turn the key while you listen to fuel pump relay clicking on. Make sure you are using a fuse with the right amp rating.
  • Check the voltage at the pump itself
  • Perform a drop test with a voltmeter. Make sure the power wire shows that there is full voltage and the grounding wire is correctly positioned.

If the electrical test shows no issue, then it is likely the fuel pump is the issue and may need to be replaced.

Fuel pressure test

  • First step is to eliminate the filter as the cause for the fuel issues. To check the filter, you need to remove it and drain excessive fuel. Use a rubber hose on the filter inlet to check the screen for debris. Replace the filter if necessary.
  • Use a fuel pressure gauge by hooking the gauge to the fuel pump test fitting. Locate the fuel pump test point and find the point where the pump connects with the filter injector rail. Then have a helper rev the engine while you check the gauge reading. Let the engine warm up a bit and then check the pressure at idle speed and the speed in the pump specifications.
  • Check fuel pressure or volume can tell whether the fuel is going from the tank to the engine or not. Use mechanical fuel pressure gauges to check fuel pressure.
  • After checking fuel pressure using the mechanical pressure gauge, perform a static fuel pressure test and connect the gauge as outline in your repair manual. Then turn ignition to on and note the gauge reading and compare to specification in your manual.

If the problem is not fuel-related you can do additional testing to establish if the fuel pump is the culprit.

Why is My John Deere Fuel Pump Leaking?

If your John Deere mower is leaking oil, it is important you address the issue promptly before it causes serious damage to the engine. While the issue could sometimes indicate a major mechanical failure issue, other times it is only a minor problem that won’t cost you a lot to fix. It is thus important to identify the cause of an oil leak.

Several things could cause the fuel pump to leak:

  • A cracked oil seal- start by checking the oil seal when you notice an oil leak on a John Deere mower. The seal’s location and shape will differ depending on the model of your machine, but in most cases the leaking one will be located just above the blade, below the engine. To fix, get a replacement seal, pry the old one out and press the new one firmly into position. Ensure it doesn’t wrinkle or bend, to avoid another leakage.
  • Loose drained plug- If the drain plug is not properly replaced after changing oil or it has become loose, oil may leak from this part of engine.
  • Cracks or holes that are not supposed to be in your engine will also leak oil.
  • Leaving the vehicle on uneven ground for prolonged periods of time can also cause an oil leak.
  • An oil leak could be coming from the area where you add oil to the engine

Signs That It’s Time to Replace Your John Deere Fuel Pump

A bad or failing fuel pump will produce various symptoms that tell the driver of a potential issue. The following are the symptoms you should watch out for in your John Deer as could mean the fuel pump’s time is up and needs to be replaced:

  • Difficulty starting
  • Whining noise from the fuel tank.
  • Loss of power when the tractor is under stress- such as driving uphill or carrying a heavy load
  • Low gas mileage
  • Vehicle will not start

How Long Will a John Deere Fuel Pump Last?

Fuel pumps can last for over 200,000 miles in some cases. Fuel pumps are not part of a regular maintenance schedule and only need to be replaced when they fail.  After 100,000 miles, the pump failure is likely enough that you should consider replacing it when you are replacing a part in the fuel system nearby.

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John Deere Diesel Engine Hard to Start

If your John Deer is difficult to start or will not start, this could be due to any one of the following issues:

  • Fuel pump is not adjusted properly or dirty.
  • Fuel shut-off valve is closed.
  • Air in fuel line. Bleed fuel line.
  • Improper starting procedure. Review starting procedure.
  • Cold weather. Use cold weather starting aids.
  • Worn or deformed piston rings.
  • Gasket blow-by or leakage.
  • There is water, dirt, or air in the fuel system. Drain, flush, fill, and bleed system.

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