Switching back to petrol under load

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VikG
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Switching back to petrol under load

#1 Post by VikG » Sun Mar 08, 2020 8:28 am

Hello,

As an LPG enthusiast that has driven quite a lot on LPG, I've just encountered my first issue and I have no indication on anything being faulty.
I service my car and LPG every 6-7k miles to ensure all filters and oil are up to date (I do drive a lot).
2 days ago I started experiencing that whenever I reach a hill or just press the gas - the car turns back to petrol and the indication that shows me how much gas there is in the bottle and when I am on petrol/lpg - starts beeping like there is no LPG in the bottle.
This started about 10 miles after I fueled up in a Jet petrol station. It happened once, then it was okay for about 40-50 miles and then it started happening on pretty much every hill or every time I get on the motorway and try to get to 70mph. Once the road is leveled and I drive on cruise control - it works on LPG.
On uphills I can feel how the car is struggling for fuel (same way it feels when I have just a few liters of LPG in the tank). So I decided that I might have fueled air or something. Wen on, put on more LPG in a different petrol station - issue remains.
I've changed the small filter on the vaporizer - no change. I have ordered a new filter that sits before the injectors, but when looked in it with a flashlight - it was completely clean, also the small filter in the vaporizer was barely dirty.
There are no indications of faults, no lights. On idle it runs as it should - no rpm changes or anything.
Absolutely nothing to indicate a fault anywhere. It just like I am driving with 3-5l of LPG and whenever I press the gas - the car goes back to petrol.
It is quite annoying as I travel everyday from Grimsby to Hull as I work there and there are enough uphills so it happens often.

The car is 2009 Volvo S60, 2.4l petrol, 140ps.
The Vaporizer is Tomasetto, but don't know the rest.

I have read about Simon (LPGC) and will try to contact him.
But I am open to ideas what could be causing that issue so I can try to rectify it myself.

Thank you!

Brian_H
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Re: Switching back to petrol under load

#2 Post by Brian_H » Sun Mar 08, 2020 9:50 am

It sounds like you have some sort of blockage - the solenoids are usually the area that happens, you can strip the posts out and clean them up if so. but if your seeing nothing on the filters I don't think thats likely.

You mention bottle - does this mean your using red cylinders rather than a tank? You can find with those that you end up with a lot of debris coming through if so, though I don't think you are as you mention filling up at Jet as well.

The other possibility i can think of is that something has gone wrong with the tank - most likely the pickup tube having fallen off, so your drawing in vapour rather than liquid, not really any way to check for that other than running the tank down to empty and taking the valve out to check. Though you might get a few other suggestions.

Was the car jacked up at any point close to when the problem started? Thinking if a pipe managed to get crushed possibly?

VikG
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Re: Switching back to petrol under load

#3 Post by VikG » Sun Mar 08, 2020 3:38 pm

Thanks for your replay.
Sorry, we call them bottled from where I come from. It is a standard tank on the place of the spare tyre.
Solenoids? Please explain.

No, all was good, I was running from a160 to a180, went up to 70 and the car switched back to petrol. I pressed the button went on LPG normally all was good till get back home.
Next day - it started switching back to petrol more and more often, where now it barely wants to run on LPG.

Brian_H
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Re: Switching back to petrol under load

#4 Post by Brian_H » Sun Mar 08, 2020 4:17 pm

The solenoid is the electronic valve that shuts off the gas flow from the tank, there will be 2 of them, one on the tank, 1 towards the front end. If they aren't physically gummed up, then the other possibility is that they aren't being powered as well as they should be, there will be a connection to the battery feed somewhere, most of the lpg systems power comes through that, if that isn't making good contact (either dirty, loose or corroded) then that might be all the problem is. There will be a ground connection somewhere near there too, possibly directly to the other side of the battery, an easy thing to check is to give both of them a cleaning up and see if that helps. The other place while your there to look is the lpg systems fuse, this will be in that same bit of wire usually. Pull the fuse out and check the connection underneath hasn't started going green and crusty. With both of them ruled out, your probabbly looking at either getting a laptop connected to see whats going on, or cleaning up the solenoids. you need to identify the type of tank before pulling the rear one off though.

When it switches back does it beep, or does the panel just go dead?

VikG
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Re: Switching back to petrol under load

#5 Post by VikG » Mon Mar 09, 2020 2:12 pm

Ah, yes. I have the two "clicks" when it turns to LPG, one coming from the trunk, the other from the engine.
All connections have been secured very tightly to ensure no water or stuff gets in them, but I will check them as much as I can, because the way all the cables are.. ugh, it is tough haha.
My battery is in the trunk, so I will have to look how they set it up under the hood.
I will check the fuses.
When it goes back to petrol it beeps fast, like beepbeepbeepbeep (very fast), the same way it beeps when I run out of LPG. And I have to press the button to stop, then it stays red. Once I press the button again it turns into blinking green, then turns to steady orange and there is a solid 3 second beep and all turns green - power light and fuel amount lights and they stay constant green.
Now, when I am driving and press the button, once it is supposed to go green after the orange light - it just starts beeping fast (like there is no fuel) and goes red.
I will give it a go tomorrow and see if I can open the solenoid under the trunk and clean it.
I spoke with Simon, hopefully he will be able to look at the car this Thursday if he have the time, if not - hopefully next week.

Brian_H
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Re: Switching back to petrol under load

#6 Post by Brian_H » Mon Mar 09, 2020 6:21 pm

Might be the best option is to look at what error its logging - without knowing the ecu hard to say whats wrong, but your somewhat stabbing in the dark without at least knowing what its complaining about. It wouldn't do any harm to unplug and replug the easy to get to connectors if you can though just in case. I've known my old Landi to suddenly throw injector errors for no apparant reason persistantly, reseating them sorted it. Same would apply to any of the sensors like the map sensor and gas pressure sensor.

VikG
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Re: Switching back to petrol under load

#7 Post by VikG » Wed Mar 25, 2020 7:51 am

I do apologize for the delay.

I found the issue, it was a bad connection and because it is a brand new vaporizer, the membranes have gone softer after some miles and the quantity of lpg that was going through it wasn't enough. I just increased the quantity by twisting the bolt and voila - issue resolved.

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Re: Switching back to petrol under load

#8 Post by LPGC » Wed Mar 25, 2020 12:58 pm

As supplied your replacement Tomasetto reducer will have come set at a pressure between 0.9 and 1.2 bar. Pressure tends to fall at higher engine loads when the reducer is trying to keep up with more demand for gas. Your install may have been setup to need/expect a higher pressure, in which case your old reducer will have been adjusted to the higher pressure and under load it's pressure wouldn't fall to as low as it did with the new reducer before you increased pressure on the new reducer. It's generally necessary to check reducer pressure in software when fitting a new reducer, too high a pressure can have downsides too.
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VikG
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Re: Switching back to petrol under load

#9 Post by VikG » Wed Mar 25, 2020 2:10 pm

I understand that, thus I made sure I have increased the pressure just a little bit, I played for a few days to ensure I have enough pressure for the engine to work properly even at max RPM under max load, just a few mm turning the bolt on the right and the LPG is not enough, thus I believe I have put it on the very right place (or around) if the pressure is high, it isn't with much.
Also, the vaporizer is Tomasetto, but the computer is Fobos (EaziGaz), it is a Buglarian brand LPG system and I do not believe anyone in the UK have the tools to check it.
So far - all is good, no bad noises, no extra fumes/bad smells, MPG is as normal, car runs smoothly.

Brian_H
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Re: Switching back to petrol under load

#10 Post by Brian_H » Wed Mar 25, 2020 2:32 pm

The software is freely available from their website https://fobosgas.com/en/page/28/software.html

Whats not so clear on a quick look, is what the pinout of the cable is. The hardware itself looks like KME, certainly the connector used (superseal) is used by most newer AEB and KME looms, so finding a suitable cable shouldn't be very difficult once the pinout is known.

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