Put wrong fuel in car now won’t start.

Fuel Doctor

Quite often a car does not break down immediately after a misfueling,  assuming you have drived to a petrol station to buy your fuel. Your cars engine will be hot, and a warm engine copes with wrong fuel much better than a cold engine.

This is the reason we attend so many call outs to peoples houses, or work places. Typically someone will misfuel then drive home without noticing, and then the car would refuse to start again from cold – often the next day.

Don’t worry, if you are reading this and you have a diesel car outside that wont start because of a wrong fueling – it most likely isn’t ruined , it just doesn’t like petrol.

Diesel Engines

Diesel engines work on a compression ignition, the diesel fuel gets squashed in the piston until it auto ignites, this is what gives diesels better efficiency = the fuel burns at exactly the right time every time.

Petrol ignites when a spark inside the plug , petrol is refined in such a way that it does not ignite under pressure.

But waits for a spark, so the reason your diesel car refuses to start with the wrong fuel is simply because  petrol will not ignite without a spark. So calm down, your car isn’t wrecked – its just got the wrong fuel in it.

In the case of a car that has been driven with the wrong fuel we perform a standard fuel drain and remove the contaminated fuel that is in the tank.


We then open the fuel lines as close to the engine as we can and then suck out the remaining bad fuel.

With our fuel scavenging equiptment, finally we put the correct fuel in and draw this up to the engine with our pump, so when we start the car. The correct fuel is injected into the pistons.

This is where our experience and expertise comes in. There is some magic sauce and know how to quickly and safely getting a car started after a misfuel. If it is done wrong, or by an enthusiastic DIY mechanic. Starter motors can get burnt out, fuel lines not reconnected properly, batteries flattened, or at worst a fire.

If you have misfuelled and your car won’t start, call us, or any experienced fuel draining mechanic, its a simple fix and takes less than an hour.

So if you wrong fuel give us a call.

Put wrong fuel in car now won't start.

6 thoughts on “Put wrong fuel in car now won’t start.”

  1. I’ve put old stale petrol in my car now it won’t start what should I do to get it started. Should I just keep adding fresh fuel will that make it start thanks

    1. Hi Scott,
      Unfortunately, if the vehicle has already fallen foul of the stale fuel you will most likely need to get it drained out and have the system fully purged and re-primed with clean fuel.
      The Fuel Man

  2. Hello i accidently put petrol in my diesel car drove it for approximately 45 miles and now it won’t start at all. I topped it up with £15 of diesel after and we managed to get it started,drove it another 5 miles and now it won’t start at all. Is there anything you can advise me on getting the engine running again? Thanks

    1. Hi Christian,
      Sorry to hear about your situation. Unfortunately the only way to ensure that the vehicle gets back up and running without any threat of further damage is to get the contaminated fuel drained out and the fuel system flushed and re-primed with the correct fuel.
      Give me a call and I will be able to help.
      The Fuel Man

  3. My diesel car suddenly would not start on Monday morning, after driving home on Friday from work and putting £10 of fuel in on the way home. I simply cannot remember if I put the wrong fuel into the car. I visually tried to remember what I did, but because I drive both petrol and diesel and fill them both, I just could not identify which I had used when last filling the diesel car. Crazy! I am usually very careful, but the possibility of having put the wrong fuel in is something I can’t ignore. How can I check this in order to be absolutely sure one way or the other?

    1. Hi Marti,
      What I would suggest is to take the filler cap off and smell it. If there is petrol in the tank you will be able to smell the fumes.
      If you are unsure of what it should smell like, have another diesel car park next to you and open the filler cap of that. Then compare the smells of the two. This should tell you one way or the other.
      The Fuel Man

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