L4330 Intermittent Crank but No Start

[FTG-05]

Just over 1000 hours; fuel is above half full. Ran fine, then shut it off to do some work, went to restart, wouldn't start, no sputter, no smoke, good cranking otherwise.

Came back an hour later fiddled with the PTO switch, cranked and started right up. Did some more work, happened again, PTO switch no effect, then restarted. It *appears* to be clutch related, but I've started it many a time without sitting in the seat and the clutch disengaged. When it starts normally, it usually starts within a second or two of turning the switch; it starts very fast.

I got it back to my shop and it's raining so I have some time to investigate it before needing it again.

In another older but similar thread, someone mentioned the fuel pump solenoid; where is that located?

LMK if you have any questions.

Thanks,

 

[moship]

From your description it sounds like the starter is spinning the motor over without issue, but for some unknown reason the engine does not fire and run on its own. Is this correct?

If the above is accurate, the PTO switch prevents the starter from being engaged, not for firing. At least that is my understanding of the operation of the safety switches.

The stop solenoid is located on the front right hand side of engine above the oil filter and in close proximity where the throttle cables attach. There is also a relay in the electrical circuit for the Engine Stop Solenoid.

Good luck!

 

[FTG-05]

Starter spins just fine (assuming it's in neutral). Just an intermittent no start, like it's not getting any fuel. Due to the intermittencies, I believe it has to be electrical related. When it starts, it runs fine, no change from normal.

 

[Dave M7040]

Starter spins just fine (assuming it's in neutral). Just an intermittent no start, like it's not getting any fuel. Due to the intermittencies, I believe it has to be electrical related. When it starts, it runs fine, no change from normal.

It would be worthwhile to go to Kubotabooks.com and download the WSM for the closest model to your tractor.
Index of Kubotabooks/Tractor Owners Manuals/

Newer tractor have a computer box called an "operator presence control." Unlike safety switches on older tractors, where the switches were hard wired into the circuit, now with OPC, switches are sending signals to this computer and it is deciding if the tractor can be started, can be running etc.

Do any error codes show up on your dash?

Dave M7040

 

[FTG-05]

Dave, I have thw SM, but it's not very well organized IMO. For example for Troubleshooting, there is no entry for crank but no start that I've seen.

There are no errors on the dash. My l4330 was made in 2005 IRC, hence, hopefully no computer.

Thanks,

 

[Dave M7040]

Dave, I have thw SM, but it's not very well organized IMO. For example for Troubleshooting, there is no entry for crank but no start that I've seen.

There are no errors on the dash. My l4330 was made in 2005 IRC, hence, hopefully no computer.

Thanks,

Because I do not know your particular model my comments will be generic. Obviously, with the engine cranking but not starting, the fuel supply is the issue.

The engine's fuel supply is cut off in one of two ways using a solenoid attached to the fuel injection pump.

In one design, the solenoid pulls the fuel supply open and the engine can start. The solenoid has two internal coils. A pull coil and a hold coil. The pull coil has lots of strength but will overheat the solenoid so a "hold," coil is used to keep the engine running.

In the other design, when you turn the key to OFF, a timer applies power to a solenoid which cuts off the fuel supply. The timer only keeps power applied for a few seconds. This system is not used as often as you can end up not being able to shut off the engine.

In the manual you have, look for the procedure to check the engine stop solenoid. Usually measuring resistances of the coil(s).

Dave M7040

 

[FTG-05]

Will do, thanks!

 

[FTG-05]

Well crap! It went from crank but intermittent no start to now it's intermittently cutting out when put in gear!

I had previously checked engine stop solenoid per Dave's recommendations above for the crank but intermittent no star; and it appeared to stop; it would crank and start just fine. Hence, I decided to run it up and down my one mile gravel to clean it up from all the rains we've had the last couple months.

Got half way down the road, working fine, when all of a sudden, it stopped, dead in it's tracks. Neutral, restarted just fine; put it in gear (forward) - Dies. Put it in Reverse - Dies. Got a tow back home from a neighbor (with a MF tractor). Halfway home, it started and remained running in gear. How embarrassing.

Obviously, there's some intermittent electrical fault; whether it's related to the crank but intermittent start, I don't know. The only previous problem I've had with this machine since I got it Aug. 2013 is the 5 amp Key Stop fuse blew about 3 years ago. Replaced it and have had no problems since.

Anyone else experience this problem? What did you learn and how did you fix it?

Thanks!

 

[Dave M7040]

Dave, I have thw SM, but it's not very well organized IMO. For example for Troubleshooting, there is no entry for crank but no start that I've seen.

There are no errors on the dash. My l4330 was made in 2005 IRC, hence, hopefully no computer.

Thanks,

Since you have a Service manual, is it an electronic one you can make available so others like me can study it?

I would be studying the material related to the "Operator Presence Control,"

Unlike simpler machines where various safety switches are just wired in series with the start relay or the engine stop relay, the OPC is a small brain which receives signals from all the various switches and decides if the engine should be allowed to start or should the engine be allowed to keep running.

I suggest you read this thread about a B2650 from the Orange forum only because it will give you some insight into the OPC system and how you can trouble shoot it.
B2650 OPC fuse keeps blowing - OrangeTractorTalks - Everything Kubota

Dave M7040

 

[FTG-05]

Since you have a Service manual, is it an electronic one you can make available so others like me can study it?

I would be studying the material related to the "Operator Presence Control,"

Unlike simpler machines where various safety switches are just wired in series with the start relay or the engine stop relay, the OPC is a small brain which receives signals from all the various switches and decides if the engine should be allowed to start or should the engine be allowed to keep running.

I suggest you read this thread about a B2650 from the Orange forum only because it will give you some insight into the OPC system and how you can trouble shoot it.
B2650 OPC fuse keeps blowing - OrangeTractorTalks - Everything Kubota

Dave M7040

PM sent. I forgot to add that my service manual is for the L3130, L3430, L3830, L4330 (mine), L4630 and L5030. It doesn't say anything about the M7040. Sorry.

Spent some time looking over the electrical diagrams for my L4330. Specifically the diagrams on page 9-M4, 9-M5, 9-M33, and 9-M35.

It looks like the common factor is the OPC seat switch.