Citroen Xantia 1.9TD Engine Management Light on

[weety]

Hi Guys

been running my xant on veggy for quite a while without probs but its got a strange one now.

When the engine is put under load the management light comes on and the engine loses power.

I havent had a chance to check yet but i will look for air leaks and change the fuel filter tomorrow.

But does anyone know what the management system measures? is the car desperately trying to tell me it is suffering from fuel starvation....or could it be a more er interesting problem

or do i have an electrical problem

cheers

peter

[XantiaMan]

Hi Guys

been running my xant on veggy for quite a while without probs but its got a strange one now.

When the engine is put under load the management light comes on and the engine loses power.

I havent had a chance to check yet but i will look for air leaks and change the fuel filter tomorrow.

But does anyone know what the management system measures? is the car desperately trying to tell me it is suffering from fuel starvation....or could it be a more er interesting problem

or do i have an electrical problem

cheers

peter

You have an air lock possibly because of a blocked fuel filter or clogged fuel pick up in the tank. Mine did the same after running some crap biodiesel.

[CitroJim]

That'll be right Gareth Spot on!

Nothing deadly serious 8)

I would however, in addition, check the fuel return line is clear back to the tank. It does sometimes block when running veg and the effects can be nasty, such as a fuel filter housing rupture by the fuel thermostat (the white bit that is visible near the filter housing base).

Fuel starvation and/or air will upset the timing servo in the pump that uses hydraulic pressure to function. The fuel is used as the hydraulic fluid.

The Engine Management (K) Light will come on if the timing the ECU tries to set on the pump for a given operating condition of the engine is not confirmed by the TDC sensor and the No.3 Injector Needle Lift Sensor. Basically, the ECU sets a timing value and measures the offset between the TDC sensor signal and the Lift Sensor to confirm the timing is correctly set. If there is air in the hydraulic supply to the servo, this will cause a timing error too large for the ECU to correct..

When the K Light is on, the pump defaults to a fail-safe fully retarded timing, hence the loss of power...

The sensors are OK, otherwise the K light would always be on.

[weety]

given the fuel system a good clean out changed the fuel filter and its fine again now

sailed through its mot again today (just an advise that a lower balljoint is starting to go) i just wonder how many years i can keep it going