Page 1 of 2 12 LastLast
Results 1 to 10 of 11
  1. #1
    New Member
    Join Date
    Jan 2013
    Posts
    17
    Location
    dassel, mn
    Tractor
    JOhn Deere 445

    Default John Deere 445 MAP sensor possibly bad

    I have been chasing a problem for a month now. See other posts under my name if needed for complete history.

    I have a JOhn deere 445 year 2001. Fuel Injected, 22 HP kawasaki enigne. WHen trying to start it when cold, it fires and backfires and spit and stumbles. But, if I use a very small shot of starting fluid it fires off and start to run. Once it warms up it will run, but the governor cycles the engine from low RPM to higher RPM continously. I took off the small vacuum hose leading to the MAP sensor and the cycling stopped. I wouldn't say it is running great, but it runs and I can blow snow. Now if I hook the hose back on while the engine is warm it goes back to 1 second cycling. If I unplug the MAP sensor it dies out completely.

    Becasue the MAP sensor costs so much ($275) I was wondering if anyone knows of a way to "fool" or bypass the MAP sensor to see if I can get a better handle if it is actually the MAP sensor that is bad.

    If anyone has any suggestions, please respond. Oh, by the way I did replace the plugs, fuel filter, air filter. Also changed the small 2" hose thats on the fuel pump inside the tank.

  2. #2
    Silver Member Eric Barney's Avatar
    Join Date
    Apr 2012
    Posts
    148
    Location
    Palm Beach Gardens FL
    Tractor
    JD X540

    Default Re: John Deere 445 MAP sensor possibly bad

    I am not familiar with the EFI on this tractor engine. But, I am very familiar with automotive systems. The MAP sensor measures: Manifold Absolute Pressure. Un-plugging the vacuum to the sensor tells the MAP sensor that NO vacuum exists in the intake manifold. This causes the control module to increase the fuel, as no vacuum is a full (wide open) throttle condition.

    My guess is that you have a lean fuel mixture condition, and the MAP sensor is working as it should. EFI systems are best diagnosed with a good technical manual, a good automotive type digital multi-meter, (DVOM) a fuel pressure gauge, (with the means to attach it to the pressure side of the fuel line) a vacuum gauge, and a basic knowledge of how the system works. Throwing parts at it without testing will probably cost more than paying a technician in the end.

    Other sensors will include: Coolant temperature, throttle position, and intake air temp. Also, engine speed (RPM) I doubt there is an air mass meter, but if so, it will mave a major effect if not working properly. I will bet that once tested, you will find that the fix is easy. Low fuel pressure would be my first guess. But I would verify that before buying any parts.

    Of course, buying the EFI tech manual, and diagnostic tools is not exactly practical either....

  3. #3
    New Member
    Join Date
    Jan 2013
    Posts
    17
    Location
    dassel, mn
    Tractor
    JOhn Deere 445

    Default Re: John Deere 445 MAP sensor possibly bad

    Good explanation. Thanks. I am going to buy a fuel pressure gauge. I see that I should be able to get one for about $40. If there was a small obstruction somewhere in the lines or injector, how would this effect the pressure? Also, is there a way to test the flow or volume of fuel. I took one of the fuel return lines off while it was running and there was a significant amount of gas flowing out of it. I'm thinking that if the pressure does read 25 psi I could still have an obstruction. I have blown out the lines and filter from fuel pump to injector. Have also taken out fuel injector and tried to clean, but didn't stick anything down inti injector so I'm not even sure if I did anything.

  4. #4
    Member
    Join Date
    Apr 2012
    Posts
    30
    Location
    Cornwall, NY
    Tractor
    X729

    Default Re: John Deere 445 MAP sensor possibly bad

    Eric is right on. It should not have an air mass meter as the MAP sensor measures engine load. Along with fuel pressure be sure to check fuel volume. The tech manual is a good investment and costs less on CD.

  5. #5
    Silver Member Eric Barney's Avatar
    Join Date
    Apr 2012
    Posts
    148
    Location
    Palm Beach Gardens FL
    Tractor
    JD X540

    Default Re: John Deere 445 MAP sensor possibly bad

    Volume testing is fairly easy, but is usually not needed unless the fuel pressure is low, or drops off while the engine is running. Since fuel is flowing out the return line, I would be thinking that the pressure is good, or the fuel pressure regulator is stuck open. Fuel pressure is controlled by restricting the return flow. The greater the restriction, the higher the pressure becomes. (Less fuel is allowed to return to the tank.)
    Any blockage that would clog a fuel line, would certainly create havoc in a fuel injector! The filters are designed to remove very fine particles. The valves and nozzles in the injectors must be kept clean. No dirt should be allowed to get past the fuel filter. Replace it if there is any doubt about it's condition.

  6. #6
    Silver Member Eric Barney's Avatar
    Join Date
    Apr 2012
    Posts
    148
    Location
    Palm Beach Gardens FL
    Tractor
    JD X540

    Default Re: John Deere 445 MAP sensor possibly bad

    Volume testing is fairly easy, but is usually not needed unless the fuel pressure is low, or drops off while the engine is running. Since fuel is flowing out the return line, I would be thinking that the pressure is good, or the fuel pressure regulator is stuck open. Fuel pressure is controlled by restricting the return flow. The greater the restriction, the higher the pressure becomes. (Less fuel is allowed to return to the tank.)
    Any blockage that would clog a fuel line, would certainly create havoc in a fuel injector! The filters are designed to remove very fine particles. The valves and nozzles in the injectors must be kept clean. No dirt should be allowed to get past the fuel filter. Replace it if there is any doubt about it's condition.

  7. #7
    New Member
    Join Date
    Jan 2013
    Posts
    17
    Location
    dassel, mn
    Tractor
    JOhn Deere 445

    Default Re: John Deere 445 MAP sensor possibly bad

    here's what I found. I picked up compression tester and fuel line pressure tester. Checked compression first. When I took plugs out, left side cylinder was black. But right side was white. WHen testing compression with a cold engine, left side is 180 lbs and right side is 120 lbs. This is testing it with a cold engine. After warming it up per manual I get 220 lbs on both sides. Why white on tip of spark plug on right side and black on tip of spark plug on left hand side? THoughts? Remember, I can get it to run by taking MAP sensor off. Maybe I have multiple problems???

    I need to get back to the store to find a couple of fitting so I can put the fuel pressure tester on later tonight.

    Your past input has been helpful. any additional thoughts would be appreciated.
    Last edited by bkivi; 02-07-2013 at 04:14 PM.

  8. #8
    New Member
    Join Date
    Jan 2013
    Posts
    17
    Location
    dassel, mn
    Tractor
    JOhn Deere 445

    Default Re: John Deere 445 MAP sensor possibly bad

    Eric, i was thinking about what you said about pressure regulator stuck open. So I pinched off one of the 2 fuel return lines and I hooked the MAP sensor vacuum back up and it started right up. As soon as I would release the plier that was pinching the line it woiuld shut down. So, I think you are correct in that the pressure regulator is stuck in the open position. DO you think that instead of just "shot-gunning" the regulator I should try any other diagnostics first.

  9. #9
    Member
    Join Date
    Sep 2009
    Posts
    27
    Location
    Eagleville, Pennsylvania
    Tractor
    John Deere 445

    Default Re: John Deere 445 MAP sensor possibly bad


  10. #10
    New Member
    Join Date
    Jan 2013
    Posts
    17
    Location
    dassel, mn
    Tractor
    JOhn Deere 445

    Default Re: John Deere 445 MAP sensor possibly bad

    It is running 100 % now. The pressure relief bolt located just below the fuel injector (12 mm) must have had some type of obstruction or was not seating properly. I loosened this bolt a 1/4 turn and tightened back up. This simple step and it is running good. One thing I did noticed now vs. when I was having the issues mentioned above is that now, when i turn the key and wait the 2 seconds for the fuel system to pressurize is that I can hear the fuel spraying into the throttle body. This is with air cleaner off. Thought I would mention this, as others with possible fuel delivery issues may want to listen closely when they turn the key on.

Page 1 of 2 12 LastLast

Similar Threads

  1. Looking to possibly purchase 1969 John Deere 110
    By Davileet in forum John Deere Vintage Tractors
    Replies: 2
    Last Post: 09-09-2012, 12:21 AM
  2. John Deere 445
    By caseyvand in forum John Deere Lawn & Garden
    Replies: 4
    Last Post: 07-18-2012, 01:23 PM
  3. John Deere 322 tank sensor
    By 20yrold322 in forum Parts/Repairs
    Replies: 1
    Last Post: 04-16-2012, 03:52 PM
  4. John Deere X485/445
    By grunde in forum John Deere Owning/Operating
    Replies: 6
    Last Post: 05-19-2010, 12:19 PM
  5. John Deere 445
    By Toffy in forum Customization
    Replies: 2
    Last Post: 05-04-2009, 09:40 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
© 2013 TractorByNet.com. TractorByNet is a registered trademark of IMC Digital Universe, Inc. Other trademarks on this page are the property of their respective owners.