tractor not always starting TC33D

[DerekT]

Hoping some one can give me a tip. Once my tractor is warm it starts fine. However, when it is cold i will only hear a click most of the time. It is a new battery, solenoid and starter test fine (ie if I short it out). The starter is getting over 12v from the battery, when I measure the s terminal on a cold start I will randomly get over 12v when it starts, but out of 10 tries 8 will only be a couple of volts. Once it does start then I will consistently get over 12v and it starts. Any thoughts?

 

[airbiscuit]

They are known to have ignition switches that fail.

 

[DerekT]

Thanks. I had forgot to mention that I replaced that as well. The odd thing is once I get it started it pretty consistently starts.

 

[RjCorazza]

Any of the safety interlock switches or wiring could have intermittent high resistance, causing low voltage on the trigger wire to the solenoid.
I have installed a starter relay on my diesel mowers to fix a similar issue. It's an easy and inexpensive job that basically provides 12v to the solenoid directly from the battery, rather than through the ignition switch and safety interlocks.

 

[DerekT]

Thanks RJ. That is the best diagram I have seen for this. I did wire in another relay however the trigger wire coming in doesn't consistently have the voltage. I wonder if there is a way from the original relay to bypass each safety somehow to test your other theory about resistance? That could be it. I also grounded the firewall as recommended in another post.

 

[thclimer]

The OEM switch sure leaves a lot to be desired:

TC33D Glow Plug Problem Fixed

There are a number of threads about the known starting issues that RJ has referenced above along with instructions on installing a dedicated rely to power the starter. This modification solved all my intermittent starting issues..

TC33D wont start

DX 33 Starting Problem Fixed

Have you checked your battery cables as it almost sounds like you have more of a intermittent battery issue? They can corrode from within and its difficult to see this corrosion.

 

[dlctcg]

As both RJ & thclimer above have mentioned -

I would first check the battery cables... they are a known issue on the TC's. You may have voltage there, but when they internally corrode they have to much resistance to carry the amperage needed... (especially on a cold start / prior to the engine being warmed up)

Then I would install the starter relay modification / or trouble shoot the one you have installed...

 

[RjCorazza]

Thanks RJ. That is the best diagram I have seen for this. I did wire in another relay however the trigger wire coming in doesn't consistently have the voltage. I wonder if there is a way from the original relay to bypass each safety somehow to test your other theory about resistance? That could be it. I also grounded the firewall as recommended in another post.

The add on relay should operate down to 7v I believe, so if the trigger wire won't operate the relay you're going to have to trouble shoot the wiring.
My only additional thoughts after confirming the high current cables are good and well connected, is to confirm the starter has a good ground and maybe spraying contact cleaner on (or replace) the safety switches.

 

[deezler]

I had to get the special relay to help my retired neighbor be able to consistently start his TC33.

 

[DerekT]

Thanks all really appreciate the feedback. I will report back with hopefully the solution.