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318 runs then dies with pto and forward or reverse

11K views 69 replies 11 participants last post by  chuckv 
#1 ·
Anyone with ideas mowing last nite and it died starts and idles fine but the battery light is on for some reason. And when I go to engage the pto engine wants to die and when I put it in gear it wants to die. Bypassed the hydro lever safety switch with my finger to get it to garage. seat wires I have wired together, and I have no brake pedal safety switch, so I dont know what else it could be? Any thoughts
thanks brandon
 
#2 ·
Brandon,

Sounds like you have a bad F2 fuse, fuse holder or wiring on that circuit. It is either a 2 or 3 amp fuse depending on the year of your tractor. Here is the schematic for he area in question:


Note that F2 provides the voltage to the battery discharge lamp control at the TDCM pin 5, as well as the voltage to the delay cutoff for the engine spark through the seat safety switch. The ignition can still provide spark if the hydro is in neutral AND the PTO switch(es) are off via a connection at pin 7 of the TDCM (not shown in this partial diagram...) so that is why the neutral switch manipulation allowed you to get the tractor "back to the barn."

Once you get everything working again in the F2 circuit -- please repair the seat safety switch, it is there for the protection of you and the ones you love.

Chuck
 
#4 ·
Brandon,

Those holders for the glass cartridge type fuses are notorious for being unreliable after several decades of use, heat, corrosion, etc. Just replace it with the tab type if you can... I don't have one of the older tractors in my herd, but I suspect that the 2 amp fuse is the short one. Here is what the TM1590 shows:


Chuck
 
#6 ·
Chuck,
Started mowing today and was running great untill the battery light came on and is staying on. Thats the only issue everything else from earlier Im not having trouble with. Any ideas?
Tractor starts fine maybe Ill check battery voltage at full throttle to see if its charging, Any thoughts why battery lights on?
Thanks much Brandon
 
#7 ·
Just tryed to check tractor out, it started fine and ran just short enough that I couldn't check volts a full throttle to see if it was charging. Now when I went to start it again it won't fire. Checked battery and I have 12 volts and it turns over just as fast as it did when tractor ran fine But it won't fire and battery light is on. This is very confusing cause earlyier in day it dyed then battery light came on and I ledt it along figured to cool of then I tryed it later and it fired and I ran it to garage and didnt mess with it tell now.
 
#10 ·
Thanks Mike...it was a Hail Mary hoping somebody was watching this thread...lol

Im gonna say it...like most.. My seat safety switch is 2 prong and previous owner had it marretted and taped...i soldered it and shrink tubed the connection...so it is definately not the issue
I hope its the holder...little glass fuse looks good
Ill b in touch here if that dont work.... Kinda need my snowblower in Canada right now lol

Thanks!
 
#11 ·
So.. went out and bought a blade fuse holder for the 3A fuse.. haven't installed it yet as my brain engaged..uh oh...

Weds
tractor starts fine... while in neutral I can engage the pto and it works( I just replaced pto switch thinking it was pto safety).. moved shifter lever to forward.. moved it out of the shed and ahead about 20'..opened the gate.. moved lever out of neutral and it died...put in neutral... runs fine.... in neutral..engaged pto and it dies

Today
Tested 3A fuse holder and fuse for continuity..good
Tested 20A fuse for continuity...good
Tested neutral safety switch contacts w lever in neutral and in f/r... good there
Tested seat safety bypass for continuity...good

I'm running out of options here.... it starts up and runs fine.. now dies immediately when moved out of neutral....

Ideas?
 
#67 ·
So.. went out and bought a blade fuse holder for the 3A fuse.. haven't installed it yet as my brain engaged..uh oh...

Weds
tractor starts fine... while in neutral I can engage the pto and it works( I just replaced pto switch thinking it was pto safety).. moved shifter lever to forward.. moved it out of the shed and ahead about 20'..opened the gate.. moved lever out of neutral and it died...put in neutral... runs fine.... in neutral..engaged pto and it dies

Today
Tested 3A fuse holder and fuse for continuity..good
Tested 20A fuse for continuity...good
Tested neutral safety switch contacts w lever in neutral and in f/r... good there
Tested seat safety bypass for continuity...good

I'm running out of options here.... it starts up and runs fine.. now dies immediately when moved out of neutral....

Ideas?
check the battery for a dead cell. I had this happen to me when I first got my 318. I can’t remember what the cause, but checking the battery was part of the solution.
 
#12 ·
Doesn't sound like the load is killing it. Might your drive lever be making electrical contact with a bare wire?
 
#13 ·
Ger34,

Whenever the engine spark is inhibited when you take the lever out of neutral or when the PTO is turned on, it means that the safety circuit below is working as it should:
Product Font Parallel Slope Schematic

What is not shown in the excerpt above is the connection from the key switch pin S2 to the TDCM pin 7 of X23 (thew purple #705 wire...) This connection provides a bypass to teh seat switch delay so the tractor can be started when the parking brake is set, the PTO off and the ground speed in neutral, even if there is no operator pressent in the seat. Once you change any of the safety interlock switch states, the voltagte at pin 9 of TDCM connector X22 must be present ot continue to have spark. Pin 9 gets that voltage from the seat switch via the F2 fuse.

Product Schematic Slope Rectangle Font

If your tractor is dying when you try to turn on the PTO, or move the ground speed lever it is a sure thing that the voltage on pin 9 is not present. While the F3 fuse and holder is essential, so is the seat switch and the wiring harness connecting it all up. Often a wire in the seat harness gets cut or grounded when the fender pan is removed and replaced, or just over time and vibration.

What year is your 318? Any tractor above serial number 600,305 will have the brake switch shown in the upper diagram. Your tractor is starting OK, so that is not your present issue in any case. To keep your tractor running, you need to have voltage present at X22 pin 9 when the operator is on the seat.

I am still betting the most likely cause is the fuse, wiring in that part of the harness and/or fuse holder at F2. Do you measure 12 volts on both sides of the seat switch when it is closed/bypassed? Let us know what you find.

Chuck
 
#14 ·
Thanks for the detailed info Chuck... unfortunately, being a Carpenter with limited mechanical knowledge, I'm going to have find someone to decipher your message...lol..
While I was waiting... I replaced the original fuse holder with a new blade type holder and new 5A fuse
Still same issue... starts fine.... runs.. take out of neutral and it stalls
Year of machine? Wish I knew... ifound serial # for engine.. can't find one for tractor..only a model #
I did find this under the dash.. I also found a black wire close to this with z male blade connector on it... when I inserted it into the empty slot and turned the key on... it just gave me dim dash lights... so I unplugged it
There is a blue wire coming into the base of the brown holder... but I can't find another blue wire

Oh yeah.. the black wire...isn't black usually ground in DC voltage?
 
#16 ·
This is part of the circuit for the rear PTO. The fact that you still have the loop of purple wire in it means that you do not have a working rear PTO, just the front one. The loop is necessary to provide the power through the purple circuit. In Chuck's first diagram it connects the 730 purple and 720 purple with that loop of wire.
 
#17 ·
That makes sense.. I see the rear pto shaft there.. but could never figure out how or why it didn't work

Ok...so that's not it...

I've attached a photo of my seat bypass...so we know it's not the connection... but there may be a break under the pan

guess I'm removing the cab and deck pan to see if the wires are bare
Hood Sky Automotive lighting Water Vehicle door
 
#18 ·
Ger34,

That purple jumper is supposed to be there as mentioned above...it is in harness connector X5 and would be present for any tractor that does not have a rear PTO. Your tractor does not have the electric PTO clutch assembly -- the splined shaft you see at the rear of the trans-axle assembly is just an extension of the input shaft, and would be where the actual rear drive PTO would couple up.

You can test with a volt meter to see if the seat harness is intact and the jumper at the seat is functional by probing the TDCM connector X22 pin 9 for the presence of 12 volts. This could save you removing the cab and fender deck...

Post a picture of your model number tag -- the serial number is embedded in it...

Chuck
 
#20 ·
Your serial number indicates that your tractor is an early 1986 year model. Yes the TDCM is located in the pedestal (hard to tell from your picture if that is it.) Here is a locator diagram that may help -- item #5 is the TDC Module which is under the battery tray:
Wheel Motor vehicle Bicycle tire Automotive design Organism


Chuck
 
#21 ·
Forgot to mention that when you get down to the TDCM the harness coming out of it has two connectors -- one is a dual row 8pin connector and the other is a two pin polarized connector. The light pink wire in the second connector (the two pin one) is wire #9 that you are trying to verify...

Chuck
 
#22 ·
Figured as much.. remove battery and tray to find pin 9
I started reinstalling the 4 eye bolts on top of the cab... ill call the neighbour to see if we can use the crane in his shop...which is heated btw... and lift the cabwith fender pan attached... it has to b the wire going to the seat safety switch... the tdcm is sensing nobody is in the seat and the pto is engaged... thats why it's killing the motor

Guess I'm shoveling tomorrow...lol

I'll b updating when I know more

Thanks

G
 
#23 ·
Chuck
Your wiring diagrams and detailed location of electrical components are very detailed
Do uhave a service Manual?
Where do i get one?

Thanks
G

Battery tray out... I have a red w white stripe and black going into the 2 prong connector and 1 pink and 1 black coming out




Battery connected..key on..in neutral.. I have at 12v pink connector
Key on..shifter in r..12v at pink connector

Next?
Automotive tire Tire Automotive lighting Motor vehicle Bumper
 
#24 ·
Ger, I don't know if you're familiar with "conversations", so click your avatar...box with a G in the upper right of the screen... and a drop down menu will appear. Scroll down and click "Conversations" and you'll see one from me. Bob
 
#25 ·
I'm trying to think about this from a logical standpoint...

if the motor dies when it's moved out of neutral... the safety must think there is nobody in the seat

If the motor dies when pto is engaged... it must think nobody's in the seat.. the pto wouldn't engage if your not in the seat correct?

So the culprit is the seat safety switch wiring likely?

And if the key is on and I have 12v at the pink connector... then there's no break in that circuit?

Of course.. we haven't had more than a 1/2" snow till today


Snow Automotive tire Tree Atmospheric phenomenon Slope
 
#26 ·
Ger, Your statements are correct and this leads me to faulty TCDM. @chuckv is the guru on the TCDM and he may have other thoughts.
 
#28 ·
Electric fuel pump?? See if you can locate where the sound is coming from, like a relay, particular box, circuit breaker, hour meter. Bob
 
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