John Deere 990 won't start

[Lovegreen]

I have a John deere 990, 2003. Only about 600 hours on it. worked great until 2 days ago. Would crank just fine, but not catch. It grabbed a few times, but shut off in less then a few seconds. Acted like no fuel. Checked fuse box, fuel lines, changed both fuel filters, there is fuel in all lines including one leading to mechanical fuel pump. Checked fuel pump and it is pumping fuel. Disconnected fuel stop solenoid and there seemed to be an issue. It would retract when key turned to run, but within a few seconds it would pop out again. Checked the solenoid hooked up to a 12 volt battery and it worked just as it should, holding retracted until disconnected. Did a voltage test on 3 wire prong connection going to solenoid... Red wire (pull) showed receiving good steady 12 volts. Blue white wire (hold) showed 12 volts for a few seconds and then went to 0. i am now at a loss. All wires look good without tearing them apart. Can someone tell me where to go from here? I also did a voltage test on the relay where the blue white wire was connected to. 2 connectors had 12 volt showing, and 2 did not. The blue white wire connector was one of them that had no voltage showing. But then again, I do not know if this test was correct. Just so you know, I am a widow and fairly good with basic mechanics, but I certainly would not consider myself one!!!

 

[shoehorny]

Try bleeding air out of the fuel lines. I'm not sure what the procedure is for JD tractors, but for New Holland, I loosen a nut above the fuel injectors and air pisses out. It could be air locked in your lines. Good luck!

 

[Lovegreen]

Thanks for the reply. I thought of that. But what about the issue with the solenoid hold wire losing voltage after a few seconds and shutting off the fuel supply?

 

[shoehorny]

Once again, I am not a John Deere guy, but most solenoids are attached directly to the battery by two wires. The voltage across the lugs of the solenoid should be the same as the voltage of the battery. If not, you either have a defective solenoid, bad/loose wiring connection, or the battery is bad. Make sure all the wired connections are clean and tight and try again.

 

[Egon]

Check and see if there is a thermistor for the solenoid power supply.

 

[hummertom]

On my 2000 JD 4300 the K4 Engine Run Relay controls power to the solenoid, because of the placement of the load center it is subject to dirt, moisture and corrosion, also check the diode block as the feed to the solenoid ties to it, my diode block was about $25 from JD and JD's website didn't recognize the relay part number but I found replacements on the internet for a box of 10 for $20. It is a standard automotive relay it is turned on by terminals 85 and 86 , batt power comes in on term 30 and is switched to 87 or 87A. I was having starting probs and found 2 relays were iffy and corrosion on 3, replaced all and the diode block for $50 and viola it runs.

 

[Richard]

Not the same machine, I've got a JD 930 (diesel lawn mower) and had FITS with it dying on me.

Suddenly, it worked 100% fine and I concluded I had something in the fuel line that had cleared. Then it came back. Looking, I noticed the fuel solenoid wasn't working, as weren't the blades. (electric switch to actuate)

Hmmm....now I'm thinking electrical issue. Started wiggling wires and suddenly the solenoid snapped into place....on/off/on/off.

Looked at what I was wiggling and it was a (approximate) eight wire connector. Noticed it had accumulated with crud/dust/dirt so took my air and blasted it out.

Been working fine so I'm presuming the dirt was maybe shorting something out. If this continues, I'll have to take a panel out to get good access to it and then disassemble it and clean it.