Here’s some advice if you need to do a DIY fuel drain to remove wrong fuel
If your car has an electric fuel tank pump, then there is a way to do a fuel drain yourself,
You need, containers (enough for all the fuel you have in the tank) 2 metre length of hose, and depending on type of car, some basic tools,
It is advisable if you also clean fuel (20 litres) to hand.
This works on most bmw, mercedes, citroen, peugeot, vw, audi, fords – if your diesel car makes a gentle buzzing noise for a few seconds when you put the key in the lights on position (the buzzing is the electric fuel pump priming the system) then this will most likely work.
This method is very hard on the cars battery and if it is not in good condition may flatten it, keep jump leads handy and another donor car, or be at the top of a hill
The skill level required to do this would take someone that is mechanically minded, and is aware of the safety precautions required when working with petrol and diesel.
1) Find the fuel line coming from the tank to the engine, you need to flow line to the engine, not the return line to the tank
2) disconnect the flow line and attach a hose to it, (you will need to get blue peter about it unless you have full garage facilities at your disposal)
3) put the other end of the line into a container
4) turn the key, not to starting position, just to pump priming position, this will activate the fueltank pump for 5 to 10 seconds which will send about a cupfull of fuel through the hoseline, then the pump will switch of again
5) keep repeating the same thing, turn the ignition off, then back to accessory position for 5 seconds, you might have to do this 200 times or more, it takes ages to drain a full tank.
6) once the tank is empty you will start getting foamy white fuel out, this is air that has entered the system from the empty tank
7) now pour in the clean fuel to the tank
8) repeat the key turning process again and again untill approximately 2 litres have gone thru, this purges the wrong fuel and fills the filter and lines with clean fuel
9) re-connect the fuel system and start the car
once the car starts you should fill it again to the top with clean fuel.
Petrol is highly flammable and this should be done in an area that is safe to do it,