Thread: Engine Run On

Hi there Denis, you’re not having a good run…

When you turn the key off the injector solenoids close, being a diesel it only stops when the fuel stops. So if it is running-on there is fuel getting in.

If the fuel is diesel then I would think a solenoid is failing, which for you should be a warranty on the new injectors.

However, pesky diesels will run on most oils including engine sump oil. If you have a leak allowing oil into the cyclinder(s) it will run-on, a scary scenario is an oil leak in the turbo, feeding oil into all cylinders via the inlet manifold. In this case when it lets go the engine will run-away, and only stop when the oil runs out or when you starve the engine of air (remove and block the air intake) or most commonly when the engine self-destructs above full rpm.

You could be getting excess oil from the crank case ventilator which will pass through the inlet manifold too. Remove the intercooler to EGR pipe – how much oil is in there? It is usual to be wet with oil, but it shouldn’t be dripping.

If it is at the stage where you know the conditions that will cause a run-on, you could remove the intercooler to EGR pipe just before shutdown. This would eliminate the turbo and ventilator. At this point, if there is oil coming through you should smell it.

Likewise for the injectors. You could unplug each injector just before shutdown (one injector each shutdown) which will tell you which one it is – that will be a painful experiment. The TD6 runs a little rough on 5… Unplugging an injector should log a fault (Injector 1 open circuit - to that effect). I'm not sure if that will self clear once the injector is plugged in again - did you get your diognostic kit?