JD Time Delay Module / Electrical gurus.

65specialk · Jan 7, 2012

On my JD 755 it has a TDC. What is its function and would it cause a no start situation if it was defective???

Mechanos · Jan 7, 2012

If I'm reading the schematic properly... the TDCM is nothing more than a safety interlock for the PTO. Should not affect a no-start condition.

65specialk · Jan 7, 2012

My thoughts exactly. The dealer says my no -start problem is because of this???
Thanks Dave

Willl · Jan 7, 2012

If it's wired anything like my 790, it could most certainly cause a 'no start'.

Where are you guys seeing/finding this "schematic" ?

Mechanos · Jan 7, 2012

In the service manual.

beenthere · Jan 7, 2012

Will malfunction not allow the fuel solenoid to function on startup? That is where I thought it came into play.

kuboman · Jan 7, 2012

Don't all engine functions go through the TDM. Glow plugs etc? Older version of the PCM in modern vehicles.

jd110 · Jan 7, 2012

The time delay module only affects pto operation on the 755 - or any of the other compact 55 series. If you come out of seat with pto engaged, it gives you a 1 - 2 second delay before it shuts off the pto. The engine keeps running. For a no start problem, if it doesn't crank over, the key switch sends power through the neutral start switch to the starter. In other words, the problem could be battery, cables, dirty connections, ignition switch, neutral switch, starter or wiring. If it cranks but won't start, you need to determine if the shut off solenoid is working. If not, then the solenoid could be bad or wiring from switch to the solenoid.

Mechanos · Jan 7, 2012

jd110 said:
The time delay module only affects pto operation on the 755 - or any of the other compact 55 series. If you come out of seat with pto engaged, it gives you a 1 - 2 second delay before it shuts off the pto. The engine keeps running. For a no start problem, if it doesn't crank over, the key switch sends power through the neutral start switch to the starter. In other words, the problem could be battery, cables, dirty connections, ignition switch, neutral switch, starter or wiring. If it cranks but won't start, you need to determine if the shut off solenoid is working. If not, then the solenoid could be bad or wiring from switch to the solenoid.

Yep... one of the reasons those of us that have an x55 like it so much. Almost purely mechanical with non of that electronic crap. If you were so inclined, you could replace the electromagent on the PTO lever with a simple hard linkage. The only other non-mechanical item on the tractor is the fuel shut-off solenoid. If mine ever craps out, I'll probably set it up on a cable to operate the fuel shut-off.