On the PC240-6, when I turn off the key, the engine doesn't stop but the RPM decrease lower than the low idle. But the most important is that on the fuel shut off I have 3.7V when I turn the key off. If I remove the wire on the fuel shut off the engine stop. The fuel pump is a VE robert Bosch where the fuel shut off is like a cartridge with one wire on it. I measured the resistance of the fuel shut off, it is 28ohm. Is it normal to have 3.7V on the fuel shut off when turning off the engine? what should be the standard value for the resistance? maybe the resistance of this fuel shut off is smaller than the genuine that was used, so at 3.7V there is a small current that still allow a small passage of fuel to the pump, am I right or wrong?
Sounds like a diode problem disconnect alternater and see if it stops I have seen this a couple of times
Which connector I have to remove from the alternator. There is B, D and E on this alternator, which one I have to remove? By the way there is a diode close to the main connector (16 pin connector) under the engine, this diode was good. Is there another one that I have to test
I would remove all connectors from alternator just watch the main one as it is live and just see if it stops when key turned off
Which engine do you have, Komatsu or Cummins? A bad alternator might prevent you from starting but I've never seen it stop a shut down.
X2 on john c, fuel stop motor is out of adjustment due to worn rod ends is my guess...
Yep, can't seem to find a Komatsu PC240 that has a fuel shutoff solenoid, all have governor motors.
I've seen it happen on older deere excavators with stanadyne db pumps. The fuel s/o solenoid works the same way. Have seen it caused by bad diodes in the alternator, bad zener diode in the monitor circuit, or bad load dump relay. Can't say for sure on a PC240 which could apply.
The engine is S6D102-1. In fact, there are two types of fuel pump used on this engine. The first one is an inline fuel pump with 3 wire shut off solenoid (synchrostart). The other one is a VE bosh pump(fuel outlet from the rear of the pump) with one wire fuel shut off on the top of the pump. Anyway, it is not the governer motor that shut off the engine, so nothing wrong with the linkage (rod).
Well I found some literature. 28 ohms is correct (spec 28.5 +\-2.5ohms), have you tried just hitting it with an external 24v source? The book has a spec for both standyne and Lucas pumps but only that one for the Bosch. Both other pumps call for 24v
The S6D102 is the Cummins engine and I've not seen any machine here that has the rotary pump. Possibly there is a diode somewhere that is letting enough voltage through it to only partially shut down the engine. I would think that once the key is off the voltage disappears and the spring in the pump moves the throttle valve to no fuel.