Vermeer SC 292 won't start

[Mark Belgium]

Hello all,
Since I want to expand my stump grinding activities, I bought a Vermeer SC 292 on an auction. The machine did not start at the auction due to an empty the battery. At home after charging the battery, the machine wouldn't start anyway. It is equipped with a Kohler Command Pro EFI ECH 749. I do not have kohler diagnostics, but with a MIL installed, I was able to read the fault codes: 0351 and 0352, meaning ignition coil malfunction cylinder 1 and 2. Since the machine always fires at the beginning but then immediately shuts down, I was sure there was nothing wrong with the coils. But to be 100% sure, a continuity check was done and find OK for both cilinders. Then I checked with sparkplug testers (between plug and coil): it was obvious that at the start attempt the ignition works fine, but as soon as the engine fires (which happens fast), the ignition is shut off. I think it means that the incorporated safety system is active immediately after start, firing. I'm not touching the handles, so this safety device should not be interfering with the start. But touching the handles gives the exact same problem. That's why I'm thinking that there is a wiring problem of some kind in the machine. I cannot find anything in the manuals provided by Vermeer. I really hope one of you can help me out....
In Addition, the normally closed oil pressure switch works fine and the continuity check of the wire to ground was ok.
Since I'm not familiar with Vermeer stump grinders, there is a chance I'm not performing the correct start procedure....
Really hope on you all...

 

[ChoppyChoppy]

I'm not familiar with that engine, but I'd imagine that the oil pressure switch should be normally open. No oil pressure means an open circuit.
It closes the circuit by oil pressure.

 

[Mark Belgium]

The oil pressure switch should be normally open. No oil pressure means an open circuit.
It closes the circuit by oil pressure.

Thank you for your response. According to the service manual there are 2 types: NC and NO. I have an NC installed (tested with pressure), although an NO would be more appropriate in my point of view. The strange thing what's happening, is that it starts, fires all the time when cranked, but immediately shuts down, kills ignition after it...

 

[ChoppyChoppy]

Thank you for your response. According to the service manual there are 2 types: NC and NO. I have an NC installed (tested with pressure), although an NO would be more appropriate in my point of view. The strange thing what's happening, is that it starts, fires all the time when cranked, but immediately shuts down, kills ignition after it...

Does the service manual have troubleshooting checklists?

Just WOGs - perhaps the ECM is not sensing engine rpm, alternator charge issue, fuel pressure, etc.

Will it stay running if fed ether? That would indicate it's a fuel issue.

OR.. could be some major electronics issue and that's why it was at auction.

 

[Mark Belgium]

Yes it has: loose wires that grounds ignition circuit, interlock switch (which I cannot find), and other which I think I already checked and cross checked. Since the machine has only 450 hours and looks like 'new', I cannot find any loose wires or damaged wires or previously wire repairs.
I cannot find the wiring diagram from this machine, only from the kohler engine in the service manual, which doesn't mention the magnetic pickup, only a crankshaft position sensor. The wires are hard to follow (disappearing in a bundle), but I suppose the magnetic pick up is used for the Vermeer auto sweep system (Regulated by a Vermeer ECU) and the crankshaft position sensor is is used for position and RPM (engine ECU).
I suppose an interlock switch will kill the ignition before it fires, from beginning to crank the engine. The manual clearly states that touching the operation handles will prevent engine start, probably by the interlock switch.

 

[Mark Belgium]

In the mean time, I checked the oil temperature circuit. This check turned out to be OK. It leaves me with only one item: broken, damaged ECU. Maybe someone tried to jump start it with wrong polarity.... . Reset of the ECU was done several times and I can't think of no further actions...