DK40 won't start, no crank

[spindlewood]

2 year old DK40 - hadn't used it in about a month. Turn key, click, no crank / starter. Seemed like the dash lights were flickering when trying to start.

Charged battery off truck for an hour. Dash lights on solid bright, but still no starter.

Ideas? The service manual lists what the fuses do, but no mention of the starter. In fact, the index doesn't even list "starter".

Thanks in advance for suggestions.

 

[ritcheyvs]

Start by ensuring the interlocks (like the PTO and gear in neutral) are not preventing cranking.

 

[spindlewood]

Start by ensuring the interlocks (like the PTO and gear in neutral) are not preventing cranking.

Thanks. I should have mentioned that Neutral and PTO off were the first things I checked. Are there any others that prevent starting?

 

[ritcheyvs]

Well, the key switch has caused lots of problems so you might try squirting some WD40 or (even better) electrical contact cleaner in the key hole and then cycle the switch several times to see if that helps. Even if all other key functions are normal, the "crank" contacts could have a problem.

The start relay has caused problems for some folks. This relay is identical to the adjacent stop solenoid relay. You can try swapping connectors between these two relays as a way of testing the start relay. These are located on the "firewall" in front of the fuel tank.

Before you get deeper into the control logic you can try abrute-force starter test to verify the battery, cables, and starter are OK. There is a history of battery cable failures (under the insulation where it can't be seen) on some tractors.

On the HST model they don't use simple limit switches or relays to detect "safe" neutral or PTO setting. There is a box called the "cruise unit" that gets signals from the PTO and a rheostat on the shift lever and then provides a ground path for the start relay only when the safety conditions are satisfied. Do you get a good "neutral" light on the instrument panel when in neutral? If not, you may hae a rheostat or cruise unit problem.

 

[Highgear]

Sounds like a bad battery to me . Batteries have really gotten bad in the last 5 years . Last battery I replaced would trick a charger into thinking it had 13v. but was shorted inside and had no cranking amps . I would start there first .

 

[spindlewood]

I finally got some sun so I could work on this.

Well, the key switch has caused lots of problems so you might try squirting some WD40 or (even better) electrical contact cleaner in the key hole and then cycle the switch several times to see if that helps. Even if all other key functions are normal, the "crank" contacts could have a problem.

I Unplugged the ignition switch and confirmed that when in crank mode, there is continuity between the hot and crank connectors on the switch harness. Is this sufficient for showing the ignition switch is ok?

The start relay has caused problems for some folks. This relay is identical to the adjacent stop solenoid relay. You can try swapping connectors between these two relays as a way of testing the start relay. These are located on the "firewall" in front of the fuel tank.

I unplugged the 5p ignition relay (#1 in the manual & the left most relay on the engine wall when looking from the front).
I tested continuity according to the service manual:
Relay 30 & 87 - No continuity (ok per spec)
Relay 30 & 87a - Continuity (ok per spec)
Relay 85 & 86 - The spec says it should be 84 Ohms.
I am not exactly sure how to read my meter. Touching the meter's two leads together registers a 3 on the ohm scale
My meter has 10x 100x & 1000k settings.
On 10x, it reads about 17
On 100x and 1k, it reads 3 (same as no resistance)

Note: On the harness coming into the Ignition Relay, when ignition switch in cranking position, I have power to Relay 30 .

Before you get deeper into the control logic you can try abrute-force starter test to verify the battery, cables, and starter are OK. There is a history of battery cable failures (under the insulation where it can't be seen) on some tractors.

At the starter, I jumped the (+ hot) across to where the small harness wire connects to the solenoid (?) metal tab. The engine cranked and started (which was great because I got to mow the weeds). So this should prove starter, battery and cables are ok.

On the HST model they don't use simple limit switches or relays to detect "safe" neutral or PTO setting. There is a box called the "cruise unit" that gets signals from the PTO and a rheostat on the shift lever and then provides a ground path for the start relay only when the safety conditions are satisfied. Do you get a good "neutral" light on the instrument panel when in neutral? If not, you may hae a rheostat or cruise unit problem.

The neutral light does come on solid with the power on

************
LASTLY, at the starter, when I connect the meter's leads to the (+ hot) and to the little harness wire which goes to the starter (solenoid?), when the ignition switch is in cranking position, I barely register any power (the needle moves a little).

This seems to all tell me that I am getting power to the relay but the power is not making it to the starter (solenoid?), which would point to the ignition relay being bad.

Would you agree? Thanks for your reply.

 

[ritcheyvs]

Good troubleshooting.

Assume the key switch is OK (at least for now).

The relay measurements check out but that test can't tell if there was a good connection between 30 and 87 when the relay is energized, and that is likely the problem, IMO: I suspect you have a bad start relay.

Your stop solenoid (SS) relay should be OK because the SS must have retracted (or your tractor would not have started).

Here is a subtle issue: the SS relay and starter relay are identical and side by side. That means you can change which relay does what just by swapping the connectors between the two relays. In fact, these connectors often get swapped (even from the factory) with no ill effect except the relay you think is the start relay (according to picture in the manual) is really the SS relay and vice versa.

IMO, the next step is to swap the connectors on these two identical relays. If, after the swap, the engine cranks (but maybe not start) you will know the start relay is indeed bad. If that's the case get a replacement relay. These are standard automotive items available from most car parts places (or Amazon) but best take the old one to the store as a sample. You still may not be sure which of the two original relays is bad so try the replacement in both locations (one at a time) if needed until everything works.

If switching relays does not restore the crank function the problem is more complex, maybe the cruise module or maybe something in the wiring. But check that relay first (by swapping). At least two relay problems have been reported here recently and that's easy (and free) th check by swapping.

 

[spindlewood]

Good troubleshooting.
If switching relays does not restore the crank function the problem is more complex, maybe the cruise module or maybe something in the wiring. But check that relay first (by swapping). At least two relay problems have been reported here recently and that's easy (and free) th check by swapping.

Switching the relays got it to crank.
Went to local automotive place and bought a relay. They said this relay does not have a damping resistor or diode and is not suitable for connections where computers are involved. Is this a problem, or is the relay ok to use?

Or are there computers working for either the ignition or the engine stop relay?

 

[ritcheyvs]

Switching the relays got it to crank.
...
Or are there computers working for either the ignition or the engine stop relay?

The schematic shows an external suppression diode on the start relay. so you should be OK. The HST models do have some modules, but who knows what's inside.

 

[spindlewood]

The schematic shows an external suppression diode on the start relay. so you should be OK. The HST models do have some modules, but who knows what's inside.

The bad relay was not the one shown in the service manual (#1) but was actually the one on the furthest right (#3) - for anyone who finds this thread in the future. @ritcheyvs - Thanks for your help.