Limp Mode, Black Smoke, Now won't Start

Hi All, have searched through the forum and haven't found a similar problem ( I think) I have a 2007 D40 6 speed manual, YD 25 engine (195,000 km).

Was driving along at highways speeds, applied a small amount of accelerator to overtake a slower vehicle on a hill, upon returning to cruising speed had to apply a little accelerator, lost power went to limp mode with lots of dark smoke. Pulled over and stopped restarted engine, limited throttle response, no power, dark smoke. Engine check light didn't come on.

Now unable to start, dark smoke.

NRMA diagnosed blocked fuel filter, doesn't seem to ring true, I thought dark smoke would be a sign of over fueling.

Thanks in advance for any help.

You are correct - dark smoke is overfuelling.

The exact condition is "more fuel than there is air available for the fuel to burn completely in".

This means there are two possible causes:

1) Too much fuel getting in for the usual amount of air

2) Not enough air getting in for the usual amount of fuel

The only obvious thing to rule out immediately is the air filter. If that's clean then the following things need checking:

1) Intercooler is not blocked. If the car can't start there may not be enough air getting through. Petrol is a good solvent for this purpose.

2) Open EGR valve. EGR is designed to reduce the production of NOx (nitrogen oxides), but it is only applied in mid-range throttle. During starting, at idle and at full throttle the EGR valve should be closed. The simplest fix for this is to get a 1mm stainless steel plate, do NOT use aluminium), remove the gasket from the end of the gold pipe where it meets the EGR valve on the right hand side of the motor and make a copy of the gasket but DON'T cut out the large hole. Reinstall with a good gasket cement like Permatex Ultra Blue Sensor-Safe gasket cement.

3) Fuel injectors are not blocked open. This is highly unlikely and if the car won't start, will require the removal of the injectors instead of the usual first-try of either a diesel purge or injector cleaner.

It won't be a failed turbocharger if the car won't start. The turbocharger, even if it's not spinning (like when the engine is cranking over) still allows enough air past to allow the car to start (of course). This means you can also rule out the turbo control solenoid, the vane actuator, the vacuum pump and vac hoses too.

Thanks Tony,

Will start the investigation today, will let you know what we find.

Hi all,

Found that the "flap" on the end of the arm in the EGR valve had come off. I was lucky that the engine was shut down by the ECU. Have replace the EGR Valve and after an appropriate time will blank the EGR system. Repairer wouldn't install a blanking plate. Also whilst checking the ECU with their scan tool they found that there no injector codes in the ECU. This was also corrected.

you can easily block off the egr unit yourself, the blanking plates are cheap on ebay .