TC40A Intermittent Start Issues

   #1  

billybonds

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Jan 5, 2017
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Medford
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New Holland Workmaster 35
I inherrited a 2004 TC40A with the adjacent horse farm I purchased. The farm had been leased out for about 5 years before this, I this tractor was used and abused without maintenance for at least all of that. I've been trying to bring this tractor back to glory, and the most annoying thing is this intermittent starting issue. It sounds so similar to all these other threads, but after hours of reading, I cant pinpoint an actual fix that applies. It can start fine 4-5 times in a row, it can start after a few turns of the key, or it can take 3-4 minutes. Assuming it's not starting, here are the symptoms:
1. Turn the key and hear the click, but does not attempt to crank
2. Continued attempts do eventually result in a start.
3. Too many consecutive failed starts and the red PTO light comes on and it will no longer click. This requires turning the key off and letting it sit for 5-10 seconds before starting again.

Local dealer has tried to diagnose the problem with no success. Multiple saftey switched have either been changed or jumped. Electric and wiring is no my strong point, but the dealers mechanic said no ohms are getting to the starter when it does this???

One of the previous tenants apparently tossed the manual, and I cant find a manual online for the TC40A specifically. Assuming this model and year are largely identical to similar models within a few years of this one, I've seen mention that it could be the starter solenoid? Only problem is, I cant find it on this tractor, and cant find an actual diagram to locate it. Is it just built into or part of starter itself? I've found wiring diagrams that specify the solenoid, but as stated, electric is not my strong point, and reading a wiring diagram may as well be Chinese.

Is that my solenoid part of the entire starter assembly? Main power goes from the battery to the lug in the first picture, second picture is the other side. Is the solenoid under that brass cap?
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   #2  

dlctcg

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256
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CT
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New Holland TC40D, Lull 400, IR SP-48 Roller
So yes the solenoid is part of the starter but based on your description I would check / diagnosis some other thing prior to continuing to throw money at it.

NH Have a few known gremlins that can pop-up: (these are the things I would be checking first.)
1) Battery Cables both positive & ground (description below)
2) Check for a lose / or chaffed ground wire
3) Ignition Switch -
4) Voltage at the Starter Solenoid -



Cable Test:
Older New Holland battery cables often corrode inside the terminal where it is sometimes impossible to see; not sure it was an issue with your particular yr / model... You will often have voltage so everything seems good. (gauges & all are working). So you will have voltage but they will not supply the required Amperage.

You can test if there is an issue with your existing battery cables pretty simply.

Remove the negative battery cable & then take a negative jumper cable wire and place it on the bare negative post of your tractor battery. Connect the other end to a solid clean ground of the tractor (bare metal location). Try starting the tractor & see if that makes a difference...

If that doesn't change anything you can do the same process on the positive post. Disconnect the Negative jumper from the Battery terminal. Then using your positive jumper cable attach one end to where the positive battery cable connects to the starter (connect this end first), and the other end to the positive battery post (last). Make sure the jumper cable is not able to arc to near by metal. Now reconnect the Negative jumper cable to the battery & try starting the tractor again & see if that changes anything...

Doing this process you basically bypassed the battery cables on the machine, and then can troubleshoot from there. I wouldn't put any more parts on it till I checked the factory cables...


Ignition Switch:
These are also prone to issues & can cause the issue your describing. (I'll see if I can find a testing procedure).... but check to see if you have voltage at the starter solenoid when the key is turned to start..

Starter Solenoid:
Make sure you have 12V at the starter solenoid whe you turn the key to START...

If you see voltage only sometime I'm thinking it either a spotty ground or Ignition switch.

If you are see voltage Each time to turn the key yo the START position but it is less than 12V this will definitely cause an inconsistent starting issue. This circuit shares the voltage source this the glow plug timer (& I believe passes through some of the safety switches). Overtime the wiring & connection get dirty / lose there ability to pass the voltage. You can modify the current wiring & add a dedicated relay for supplying direct power to the starter solenoid via the same circuits. I did this on our TC40D & it made a big difference for our machine

This is a pic of the relay I added:
 

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   #3  

thclimer

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Eastern NY
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New Holland TC33D, Massey 1736
The circuit mention by "Dlctcg" for supplying direct power to the starting solenoid is mentioned in post #51 of this thread, I suspect you have a issue with the safety switches that have been jumped/by-passed:

 
  
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#4  
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billybonds

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New Holland Workmaster 35
Definitely not. The only bypassing that was done was in order to troubleshoot. All switches have been tested and/or replaced with no change in symptoms. There may be issues somewhere else in the wiring, but it's not coming from the switches themselves.
 
   #5  

dlctcg

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New Holland TC40D, Lull 400, IR SP-48 Roller
Definitely not. The only bypassing that was done was in order to troubleshoot. All switches have been tested and/or replaced with no change in symptoms. There may be issues somewhere else in the wiring, but it's not coming from the switches themselves.

Yeah... My thinking is along the same lines as yours. I find, usually if I have safety switch issue you need to move a lever / jumper something to get the machine to start... The fact you just turn the key again (& again) with no other action to get it to start make me go back to running down the things I mentioned above.

I'm not saying one (or more) are definitely the issue but all of those can cause the situation your describing & all can be tested pretty easily without cost with a multimeter & some jumper wires... so no out of pocket to diagnose.

I've had battery cables that look close to brand-new & be the problem on a buddies NH.
 
   #6  

thclimer

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Eastern NY
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New Holland TC33D, Massey 1736
When you stated
Local dealer has tried to diagnose the problem with no success. Multiple saftey switched have either been changed or jumped.

I had assumed switches were jumped by the previous owner, sorry my bad.

Have you tried to give the starter a tap when you turn the key and all you hear is a click as I'm wondering if the starter solenoid is just stuck?
 
   #7  

Anakist

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Jan 21, 2021
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Central Qld, Australia
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New Holland TC40DA
The weak start relay or whatever it is called is what you need.

Exactly the same symptoms as my TC40DA. Sometimes it would start right up. Sometimes it would click and the lights would dim. Then the PTO light came on.

From what I can make out it is degradation of the circuit from the battery through the ignition switch through the solenoid trigger and to ground. Put a relay in so the "start" circuit triggers the relay and a new wire from the battery positive of the solenoid goes through the high current contacts to the trigger circuit of the solenoid. Mine starts in seconds now. Every time.

I will draw on one of your pics for clarity...

James
 
   #8  

Anakist

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Central Qld, Australia
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New Holland TC40DA
On your picture of the starter I have what you need to do. The picture of the 5 pin solenoid is because they are cheap and available everywhere. This is a low power circuit. Get wire that is the same size as the original start trigger wore or bigger. 14AWG at a guess. The relay is just so the path from a *good* 12v source (the solenoid battery positive terminal) to the start trigger is good quality, not that there is a lot of current flowing through it. Wire size doesn't really matter as long as the runs are shortish (up to 18" maybe) and your connections are high quality. If you are mounting the relay up in the dash with the other relays because you are a sadist you might want to use bigger wire, but as long as you use at least the same size as the factory stuff and a decent crimper you will be fine.

Mount your new solenoid somewhere out of the way. Somewhere neat is good if you have the wire length. I forgot I needed to run a ground and didn't take enough wire so mine is just bolted on wherever for the moment.

Take the original wire off the start circuit plug and extend it to one of the trigger pins of the solenoid. It doesn't matter which, it will work either way with this type of relay but I used 85 on the picture. If you get fancy with a solid state relay or something this will need to attach to the positive trigger wire.

Run a ground (I forgot this wire so my install looks dodgy) from the other trigger pin (86 on the picture) to a solid ground. I used one of the bolts on the solenoid in the picture, but it doesn't have to be that. A bolt into the chassis or engine near where you put the relay is good. If you have a multimeter check either continuity or resistance from a few bolts to the negative battery terminal. Less than 2ohms (lower is better) or continuity light / beep is what you're looking for.

Run a wire from the large positive battery positive terminal on the starter to the high current terminal of the relay. 30 on the picture but 30 or 87 is fine. DO NOT use 87A or the starter will run all the time *except* when you turn the key to start.

Last wire is from the plug on the starter to the relay. 87 on the picture.

If you use a different relay check on it for a diagram. The circuit from the original starter wire should go through the two pins with the squiggly line to a good earth. Then the circuit from the starter positive goes through "common" (C) to "normally open" (NO) or something similar. You want the two that aren't connected in a similar relay diagram.

Hope that helps!

James
 

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   #9  

dlctcg

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Messages
256
Location
CT
Tractor
New Holland TC40D, Lull 400, IR SP-48 Roller
The weak start relay or whatever it is called is what you need.

Exactly the same symptoms as my TC40DA. Sometimes it would start right up. Sometimes it would click and the lights would dim. Then the PTO light came on.

From what I can make out it is degradation of the circuit from the battery through the ignition switch through the solenoid trigger and to ground. Put a relay in so the "start" circuit triggers the relay and a new wire from the battery positive of the solenoid goes through the high current contacts to the trigger circuit of the solenoid. Mine starts in seconds now. Every time.

I will draw on one of your pics for clarity...

James
There is no true telling "what you need" till you diagnose the issue.... Been there done that.... I do agree that installing a starter relay circuit is a good idea... (I've done it with great results on multiple NH's)... but troubleshoot the problem correctly so you know what the issue is key....

I checked & didn't save the tread I had found when I did our TC40D (I give credit to @thclimer for referencing it)....The PDF is the below...

Again it's not mine & gladly give credit to the OP... Thank you @thclimer

But I would still run through the diagnosis outline I described above to verify the issue you are having.... Any of them (& others) can be causing your issues.
 
  
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#10  
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billybonds

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Medford
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New Holland Workmaster 35
another symptom to add, the starting issue is much more prevalent when the machine is warm. When cold, it almost always starts right up. It’s when I run it to operating temperature, shut it off, and try to start it again that it’s the hardest to start again. Does this tidbit help with a diagnosis?
I’ll try to work on this relay this week. I know nothing about this kind of electrical, but I’m not afraid to give it a go. I assume I can get all this stuff at Tractor Supply?
 
 
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