L48 ignition bypassing glow plug

[ejayb9]

Hello. I have an L48 and every once in awhile when I turn the key the engine tries to start right away. Normal operation is turn to the first stop on the key switch to warm the glow plugs, when the glow plug indicator light goes out then I turn the key to the next stop and the tractor will start. But sometimes it just tries to start and it won't because the plugs haven't warmed up. It just tries to turn over. I think it has to do with the foward/reverse pedal because if I press on the pedal while the key is turned it stops trying to turn over. But that's just a guess. Does anyone know what might cause this? Thank you.

 

[fried1765]

Hello. I have an L48 and every once in awhile when I turn the key the engine tries to start right away. Normal operation is turn to the first stop on the key switch to warm the glow plugs, when the glow plug indicator light goes out then I turn the key to the next stop and the tractor will start. But sometimes it just tries to start and it won't because the plugs haven't warmed up. It just tries to turn over. I think it has to do with the foward/reverse pedal because if I press on the pedal while the key is turned it stops trying to turn over. But that's just a guess. Does anyone know what might cause this? Thank you.

I don't use my L48 in the 6 coldest months of the year, so have never even needed the glow plugs.
It starts easily without any glow plug assistance.
I don't know if my glow plugs actually work!

 

[RickB]

Sounds more like a faulty key switch. The neutral safety switch on the hydro pedal linkage is doing its job just fine.

 

[rbargeron]

Are you saying that your starter turns when the key is only in the first position?

The L48 glow plug system has a controller & relay. With key ON, glow plugs run for the right time, based on temperature. Key at START runs the starter. My glow light was only brief & would come back on when running. Glow relay was not clicking in. A new controller 16415-65662 straightened mine out.

 

[rbargeron]

Its the same system on Lxx00, Lxx10, L35, L48, maybe others.

 

[ejayb9]

Thank you everyone for responding. The problem went away overnight. But today when I went back to start, same thing happened.

@RickB I have a brand new, fresh out of the bag, OEM switch, I bought just because I thought the same thing. A key problem. I plugged in the new switch and it didn't fix it. Same behavior.

@rbargeron Yes. The starter is turning in the very first position. Normal behavior in the first position is for the glow light on the dash to light up for about half a second. Then after the dash light goes out, I turn the key to the second position and the tractor starts up. But it's skipping the glow plug in the first position and the starter just chugs away. Doesn't start. Nothing happens if I turn the key to the second position. No change from the starter. It just keeps on trying to turn over but won't do it.

There's a small solenoid looking thing under the tractor that retracts when I push on the pedal. It's got a wiring harness coming on the back of it. I was thinking of changing that to see if there is any affect.

 

[fried1765]

Thank you everyone for responding. The problem went away overnight. But today when I went back to start, same thing happened.

@RickB I have a brand new, fresh out of the bag, OEM switch, I bought just because I thought the same thing. A key problem. I plugged in the new switch and it didn't fix it. Same behavior.

@rbargeron Yes. The starter is turning in the very first position. Normal behavior in the first position is for the glow light on the dash to light up for about half a second. Then after the dash light goes out, I turn the key to the second position and the tractor starts up. But it's skipping the glow plug in the first position and the starter just chugs away. Doesn't start. Nothing happens if I turn the key to the second position. No change from the starter. It just keeps on trying to turn over but won't do it.

There's a small solenoid looking thing under the tractor that retracts when I push on the pedal. It's got a wiring harness coming on the back of it. I was thinking of changing that to see if there is any affect.

Do you have the L48 workshop manual?

 

[pmmully]

Hello. I have an L48 and every once in awhile when I turn the key the engine tries to start right away. Normal operation is turn to the first stop on the key switch to warm the glow plugs, when the glow plug indicator light goes out then I turn the key to the next stop and the tractor will start. But sometimes it just tries to start and it won't because the plugs haven't warmed up. It just tries to turn over. I think it has to do with the foward/reverse pedal because if I press on the pedal while the key is turned it stops trying to turn over. But that's just a guess. Does anyone know what might cause this? Thank you.

My L48 glow plug light stays on all the time. Causes?

 

[rbargeron]

Attached are pages from the L48 WSM with the start system wiring diagram and its functions.

The symptoms point to the glow relay and/or the controller. The controller is known to fail so I'd look there first. See post #4 for a link to new ones - several under $40. Please post back on what cures your rig. Dick B

 

[ejayb9]

Attached are pages from the L48 WSM with the start system wiring diagram and its functions.

The symptoms point to the glow relay and/or the controller. The controller is known to fail so I'd look there first. See post #4 for a link to new ones - several under $40. Please post back on what cures your rig. Dick B

Thanks, somehow I missed post #4 when I had originally read the replies. I did order a controller off Amazon, and got that yesterday. Plugged it in and no change. I ordered a new glow plug relay this morning- FedEx ground shipping so might not see that until Friday.

I'll update once I get the part in, if that fixes the problem. Thank again!