Xantia Blocked Injectors?

[davidjgray308]

I have a 94 Xantia 1.9D (lucas pump) that is lacking in power even for a 1.9D.Not long after acquiring it, I experimented with vegetable oil refined using a transesterification process. Soon afterwards I began to experience a lack of power and also a situation where the idle speed would drop to around 900rpm on coming to rest and then a second or so later would pop back up to 1000 instead of coming to rest smoothly (anyone familiar with this situation?). I'm told this was down to a blocked injector and have used much injector cleaner and more or less got rid of it although it is not like before I used the veg oil. I have also been through a number of fuel and air filters but power still seems to be lacking and not delivered smoothly. I have tried injector cleaner direct in the fuel filter housing instead of mixed with fuel. I know now that veg oil shouldnt be used with Lucas pumps - is it possible the pump is damaged in some way or is it more likely the injectors are still blocked, despite my zealous cleaning? Many thanks in anticipation, Dave.

[CitroJim]

Hi Dave,

Welcome to the forum

Generally, diesel injectors do not block. There's too much pressure behind them to

Yes, I'm sorry to say the pump is most likely damaged. I've just stripped a Lucas pump that died running bio-diesel and it was in a terrible state. They're delicate little flowers, these Lucas pumps and very intolerant of anything but the finest diesel.

I have no proof it was the bio-diesel that was the the full cause of the failure of the pump in question but the pump was full of corrosion and muck. Have a look at this thread, from post 10 onward where I go into more detail on what I found inside this particular Lucas pump. What I thought was just dirt in some places has turned out to be corrosion as well, suggesting the bio was a bit watery.

The symptoms you have point to a sticky, gummed fuel metering valve and the pump I dismantled exhibited similar symptoms to yours just before it died.

The lack of power may be down to excessive leakage in the distributor rotor through inadequate lubrication; they eventually seize in the rotor sleeve if run on veg for an extended period. Even short spells of veg running will wear the rotor and sleeve.

A golden rule with Lucas pumps is to never run them on anything but diesel. If you really want to run on veg or bio-diesel, do a Bosch pump conversion.