My gasoline fuel pump no longer works so the gasoline no longer arrive at the engine. I’m only 2Km away from the repair shop which broke my pump, so I’m unwilling to spend more than 100€ in towing over such a short distance.

The car can work on lpg (which is not broken) only fuel provided the engine is hot enough (though that system is here only for efficiency), so it needs to run about 1 minutes before EPIGAS manufactured electronic’s allows using lpg.
Once running on lpg, I should be able to put everything back in place and drive the car normally since the gasoline system is normally switched off

I’m currently thinking unpluging the gasoline pipe and put it in a jerrycan I would be holding above the engine so gasoline can arrive through gravity to the modified 2SZFE engine.

The problem is I have no idea if this would work nor what and where I should unplug. So I need guidance on how to use the lpg system.

  • Comments are not for extended discussion; this conversation has been moved to chat. Commented Nov 30, 2018 at 12:56
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    I have rolled back the question to where it makes sense with the answers which were given prior to all of the changes. If you have a NEW question, please open one and don't completely change a question after its already been answered in good faith. It's not fair to the people who are answering, nor is it fair to people who have come to read the post after the fact. Very confusing to all. Commented Nov 30, 2018 at 13:00

6 Answers 6


Any bodge involving using gravity to feed the petrol to the engine isn't going to work - it's a multipoint electronic injection system running at much higher pressures then gravity would produce. You might succeed in doing more damage but that's about it.

Also any mucking around with the fuel system is just going to give the garage a reason to renege on doing the fix for free.

If they won't come and collect it and you can't find a tow for less than 100€ then round up a couple of mates and bribe them with pizza or beer to help you push it. Just remember to put it in neutral first!

  • I don’t to feed injectors directly but the second fuel compressor. I don’t touch the back of my car so the garage stay responsible of what they did. I don’t have mate for pushing the car this afternoon. So now where is the pipe I need to unplug ? Commented Nov 29, 2018 at 10:03
  • Any bodge involving using gravity to feed the petrol to the engine isn't going to work So wrong answer since I’m feeding a compressor with gravity instead of the engine directly. Commented Nov 29, 2018 at 10:12
  • @user2284570, motosubatsu is right. A Yaris the idle fuel pressure should be about 45 psi, which is 3 times atmospheric pressure. To gravity feed that pressure you'd have to have your fuel 43 meters (141 feet) high up!
    – GdD
    Commented Nov 29, 2018 at 11:56
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    @user2284570 What second fuel compressor? AFAIK the injectors are fed directly from the high pressure line from the fuel pump (under the back seat) you are not going to be able to replicate anywhere close to that pressure so the ECU will still see "No fuel pressure". There's no point in taking fuel lines off in the first place because what you're suggesting will not work! Commented Nov 29, 2018 at 12:01
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    You are referring to a pump used to pressure diesel injectors @user2284570. Your car has a gasoline engine.
    – GdD
    Commented Nov 29, 2018 at 12:25

You won't be able to disconnect the fuel line and pour fuel into the fuel rail because this won't achieve the 60psi of fuel pressure that most non-direct injection fuel injected cars run at. You also have no way to switch off the fuel flow when switching to LPG and there is a chance that the LPG system may not switch in because it's electronics believe there is a fault.

There is a way you may be able to start the vehicle though but I don't know if it will be enough to get you switched onto LPG. You can use products such as Bradex Easy Start or Holts Cold Start, sprayed liberally into the intake pipe on the airbox. (On a diesel I've even done this with a can of Lynx / Axe body spray). The engine will run purely on this product but I don't know if it will run for long enough to let you switch it to LPG. You may find it far easier if you have a friend come over to help.

Another option would be to have a friend with a vehicle and a straight bar or tow rope tow your car the short distance to the garage.

A final option to consider would be having the mechanic travel the short distance to where the vehicle is and changing the fuel pump at your property.

  • Thank you. I’m aware a huge pressure is required for injectors. That’s why there’s a second compressor near the engine. For lpg, it’s because I asked electronics to switch on gasoline Monday with the appropriate button the engine stopped. but I didn’t get the agreement during that day, so I didn’t felt I need to bring the car to them. I don’t have friend and I’m afraid lifting the car is required to mend it. Commented Nov 29, 2018 at 9:52
  • So now. where is the gasoline pipe on a 2SZFE engine ? Commented Nov 29, 2018 at 9:54
  • The fuel rail is on the rear of the cylinder head above the inlet manifold. It's feed pipe comes in on the gearbox side of the engine. I would strongly recommend an easy start type produce to get the engine started and warm though. Commented Nov 29, 2018 at 11:11
  • If you switch the ignition on, can you not override the LPG system to attempt to start the engine on LPG as opposed to petrol? Commented Nov 29, 2018 at 11:12
  • If the engine is enough heat, I can start it with ʟᴘɢ (there’s a button near the weel for switching to gasoline or ʟᴘɢ). But if it’s cold it refuse to switch so I have to make think EPIGAS manufactured electronic’s think the engine is hot. The system doesn’t use main engine sensors but it’s own ones and I don’t know where they are… Sure if it’s near the pressure regulator, things would be simpler. Though if it needs to get at 80℃ in order to let the system work, it would be difficult to reach such temperature without the engine. Oh, by the way, a 2SZFE works at 159 psi. Commented Nov 29, 2018 at 11:30

You safest option is to get the vehicle transported to the shop, they have the transporter / trailer to do this safely.

You say you want to save 100€, but if this goes wrong you could spend so much more.

Spend the money and keep yourself, and other road users, safe...

  • NOPE ! The answer is once lpg system is actived, the gasoline one is switched off, so I can drive the car normally. The alternative is to put the repair shop on trial and leave the car unrepaired for years. I have an agreement with them : they repair the car for free but I have to take the car myself. Commented Nov 29, 2018 at 8:41
  • So, you are not concerned with safety... I could explain how the systems are linked, but I won't (had a Discovery with petrol / lpg...)
    – Solar Mike
    Commented Nov 29, 2018 at 8:41
  • In fact the engine stoped Monday because I asked it to switch on gasoline manually. If I didn’t, I could continue to run on ʟᴘɢ or even restart this, but I didn’t had an agreement yet during that day. For the safety, it’s the mechanic who braught me into this, not you. I need to drive the car less than 5 minutes. I would even push it if destination wasn’t 6 meter above start point. Commented Nov 29, 2018 at 8:54
  • I'm not concerned about the distance, it's the safety issues and what you don't seem to understand about the systems you are trying to deal with...
    – Solar Mike
    Commented Nov 29, 2018 at 13:21

Yes you can gravity feed your fuel system - but you will need 45 meters of high pressure fuel line and a 15 story building to do it.

Modern fuel injection systems require high pressure, most of the time between 40-60 psi. You can't supply this by holding a can of gasoline above your car. Here's some math: pressure in pascals = p (density of the fuel) * g (force of gravity) * h (height in meters)

p = 719kg/m3

g = 9.81m2

So if you hold a can of gas 1 meter above your car you will get: 719 * 9.81 * 1 = 7053.39 pa = 1.023psi

You get 1 psi per meter you raise the fuel, so to get enough pressure by gravity alone to start your car you'll need to raise the fuel 45 meters up, about a 15 story building.

  • Modern 2000 era gasolines engines have « pompe à injection » in order to regulate pressure from « pompe de gavage ». So while gravity is not enough to feed the engine directly, it should be enough for the « pompe à injection » to function. Commented Nov 29, 2018 at 12:17
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    Uh, no. Those are used in diesel engines, you have a gasoline engine.
    – GdD
    Commented Nov 29, 2018 at 12:23
  • @user2284570 the fuel injection pump ramps the pressure for the injectors but it's still fed by a ~45psi line from the fuel pump and that's what it's designed to take ~1psi from gravity won't be enough and more than likely you'll damage the pump in the attempt. Commented Nov 29, 2018 at 12:49
  • @GdD modern gasoline engines have such pumps. I solved the problem through successfully wrongly hinting the insurrance the responsible garage was the nearest. Commented Nov 30, 2018 at 10:13

Your Yaris does not have a secondary fuel pump. These are typically fitted to Diesel cars due to the higher pressures needed in their injectors, wheras on small petrol cars such as yours, a single high-pressure pump at the tank is all that is needed. Therefore, as the other answers have stated, what you are suggesting is not possible.


You should, theoretically, be able to manually feed gasoline in some older engine models but such a practice is not recommended. You should be more specific about your pump and car models. Assuming it's a new car with an electric fuel pump, you should first confirm that your pump is actually broken. Check your fuses for any blown and if none found then try to remember if while on your last drive you had any "cough" behavior from your engine especially on high revs (and while on gasoline). Also you can try to diagnose it via it's check sound. On most engines with an electric pump, when you turn your key, you can hear the pump working for a couple of seconds.

  • The computer says no gasoline pressure before the engine, the same symptom than before I brought the car to the repair shop less than 10 days ago. And for having looked under, it looks like things weren’t plugged back correctly. Like I said in the post it’s a 2007 Toyota Yaris with a2SZFEengine modified by EPIGAS with EPIGAS equipment. I also confirm the starter motor is the only thing I can hear. Commented Nov 29, 2018 at 8:58
  • @user2284570 well!!! I can see no specific question so even if i could i would not be able to answer something specifically...
    – kokobill
    Commented Nov 29, 2018 at 9:28
  • As I said, what’s the guidance on how to feed my engine manually in gasoline ? Commented Nov 29, 2018 at 9:30
  • I know it’s not recommended, but as I said It’s for heating the engine on the car park, not for driving it. Is it more clear now ? Commented Nov 29, 2018 at 9:34
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    @user2284570 Well if you check the comments and answers you should see that it is NOT RECOMMENDED to do so. Probably won't work either in a new fuel injected car. I understand your frustration but you might want to take an alternative approach on this with the mentioned repair shop.
    – kokobill
    Commented Nov 29, 2018 at 9:35

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