I have a Mx5000su that is not pumping fuel. I replaced the switch under the seat. When I turn on the key it does not click like it does on my friends tractor. The motor turns on but injector pump does not pump fuel. If take of the wire to pump selinoid and jump hot wire from batery to post on selinoid makes clicking noise. Does this mean shut off selinoid is good or bad? Any help on this would be greatly appreciated.
MX5000su fuel pump problem
- Thread starter dwwright
- Start date
Check your fuses under the dash for the fuel pump circuit being blown and the fuel shut of solenoid too. Look at the back cover for the circuits. Pull the fuses out of the holder and look at the element for the type of failure, short to ground, overcurrent slow blow. You can tell by how burnt the fusee looks in the window. Come back if that isn't it. How many hour is on the run hour meter?
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304.8 hours on hour meter. I checked all fuses on left side fuse box, all good. I also took off fuel pump selenoid to friends house and hooked to his tractor and it worked. I did this just to be sure that it was not the problem
300 hours is enough time for a short to form in a wiring harness due to vibration and chaffing against the tie points on the frame. If you have a voltmeter put the black lead to a good ground on the tractor frame and the red in the terminal connector to the fuel pump lead and turn the key to on position but don't crank to start. Do you have 12 volts DC on the LED read out on the meter? If not you are not supplying voltage to the pump from your wiring harness. Turn the key off. Put the meter on continunity or Ohms scale and start a wiggle and pull test back from the pump terminal to the fuse buss. I think you will find a short circuit in the feed wire to the pump. Repair the short with new material to insulate from ground. You should be back in business. 
Hmm the only fuse panel I see is on the left side . All fuses checked out ok. Removed them and checked them with meter just in case my old eyes were deceiving me. will the safety switches prevent voltage from going to pump or do they simply controll starter? I'm thinking seat switch must go to pump in order to kill tractor if you raise up with pto on.
Hmm, I may have found the problem. Under the dash, out of sight is what appears to be some sort of fusable link. 12v-A-5. It has four prongs in it. Two on left side looks like brass, two on right side looks like copper.Two on left side has 82.3 ohms. Two on right side is open. no continuity. This thing is about 11/4 long and 3/4 wide. Does anyone know what this is or if it could be the problem.
If you jump the prongs that are open the starter turns over. It seems to have the same wire that goes to injector pump going to one of the prongs that has82.3 ohms between them.
If you jump the prongs that are open the starter turns over. It seems to have the same wire that goes to injector pump going to one of the prongs that has82.3 ohms between them.
Your 5 amp fusible link is blown (open ) and I'll just about bet your known resistance is the coil of the shut off fuel solenoid circuit. I wouldn't buy a new link until you determine why it shorted out and blew the internal fuse....
I guess my next question to Kubota would be how did the in line fuse blow over a starter relay. The relay is designed to take lots of over current during the engagement of the motor.
I think you must have mis-understood me somewhere. No fuses are blown! So far I have replaced the seat switch, starter relay which checked the same as new one with ohm meter unconnected, pto switch which checked bad, and starter. Still no voltage to injector silinoid. I really need to know where the black wire with red line goes to from injector silinoidtill switch. It seems to me that if there was a short it would have blown a fuse. So where is the open in the circuit at? Could the opc timer be causing this problem? Does anyone have a electricl diagram for this tractor?
Yes I'm confused because your post is telling me you have a blown factory "fusable Link" which is 'open'... meaning to an electrician " no continunuty" to support current flow of electrons in a series circuit. (Open Circuit)Hmm, I may have found the problem. Under the dash, out of sight is what appears to be some sort of fusable link.
If you jump the prongs that are open the starter turns over. It seems to have the same wire that goes to injector pump going to one of the prongs that has82.3 ohms between them.
If this open circuit feeds your starter relay nd you replaced the relay with no change after jumping it out with a known good 12 volt source tells me your Relay 30A terminal has no potential present to feed through your 85 & 86 terminals out to your ignition switch in the start position which with continunity allows battery voltage from Terminal 87 or 87A ( depending on N/O or N/C design ) to your sarter solenoid which acts as a magnet to pull a solid core plunger into contact with the heavy supply cable from the battery and your starter reduction gear in turn cranks the engine. Your fuel shut off solenoid is either good or bad. If you read no resistence through its coil its open, bad, no continunuty. If you touch the outside case to the feed wire terminal its shorted to ground ( no good ) meaning you must replace it or you will never get the tractor to start as factory wired. End of Story.
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