L3400 Crank no start....strange

TheCommissioner · Sep 3, 2021

UPDATE: Problem was traced to the ignition switch. There is a loose contact in the switch that we discovered by jiggling the key in the start position and confirming with the switch removed from the tractor. This will be the SECOND time the ignition switch has been replaced in a tractor with only 220 hours. Switch should last longer than that!

Have a L3400 HST bought new in 2007 and only has 220 hours. Kept under roof. It's always started up without trouble at the flick of the key except now and one other time years ago. That time it would crank but not start like now and I figured out it was the ignition switch failing to energize the fuel pump. Replaced the switch and the tractor went back to its reliable self.

Now, in the last few hours of operation it's been hard to start. Cranks fine, takes a long time to turn over. So I replaced the fuel filter and once I got it started, bled the air out of the system. Fuel tank is full. Has a new air filter from the 200 hour service. Today, it will not start no matter what even though it cranks just fine.

I don't hear any fuel pump noise when I turn the key. Could it be the ignition switch again? I am not trained on diesel fuel systems so I don't know what I am looking for if it's not the ignition switch. Does anyone have any guidance/advice for a novice non-diesel person to figure this out? Any good online instructions with photos/diagrams, tutorials, etc. for the DIYer? I want to do everything I can before I order a $ervice Call from the local dealer.

Thanks for your help, guys. Much appreciated!

sea2summit · Sep 3, 2021

Sounds like making sure you have fuel pressure is the first step. Diesel likes to run and run hot, with less than 20 hrs a year you might not be getting it hot enough and getting some wax build that could be causing some problems but I'm not a diesel mechanic so I'm just guessing there.

jaxs · Sep 3, 2021

Use volt meter to see if 12 volts is reaching fuel pump when switch is on. If not check for blown fuse and if 12 v is leaving switch. If there's 12v at pump,crack line to see if pump is building pressure,if not,replace pump. If pump is building pressure,check for 12volts at fuel shut off solenoid. If no 12 volts at solenoid,put 12v jumper to solenoid then see if tractor start's and runs. If tractor start's and run's then die's when jumper removed,look for blown fuse, broken wire and 12 v leaving switch. If there's 12v to solenoid,crack line to see if there's fuel pressure between solenoid and injection pump. If there's pressure to injection pump it's time to call in a pro to look at injection pump.

Roadworthy · Sep 4, 2021

If you've not cleaned your air filter lately you may want to check it and dust it out.

Thomas · Sep 4, 2021

Youtube has couple videos might help.

Mr_Burns · Sep 6, 2021

jaxs said:
Use volt meter to see if 12 volts is reaching fuel pump when switch is on. If not check for blown fuse and if 12 v is leaving switch. If there's 12v at pump,crack line to see if pump is building pressure,if not,replace pump. If pump is building pressure,check for 12volts at fuel shut off solenoid. If no 12 volts at solenoid,put 12v jumper to solenoid then see if tractor start's and runs. If tractor start's and run's then die's when jumper removed,look for blown fuse, broken wire and 12 v leaving switch. If there's 12v to solenoid,crack line to see if there's fuel pressure between solenoid and injection pump. If there's pressure to injection pump it's time to call in a pro to look at injection pump.

I'm having the same "crank no start" problem with my L3400!

Mine seems to have a mechanical fuel pump instead of electric pump so I can't check voltage but did pull the rubber fuel line coming from the fuel tank off the fuel filter and got a good stream so it doesn't appear to be a blockage. I checked the resistance at the fuel solenoid coil and got 1.3 ohms on pin 1 and 16.5 ohms on pin two. The workshop manual says they should read .375 ohms and 15.6 ohms respectively. Both readings seem to be 1 ohm high. I'm wondering if that constitutes a bad coil that needs to be replaced? Hope not! I also checked the electrical connector for the solenoid and got 12 volts when the key was in the on position. Next step is to see if there is any fuel pressure to injection pump.