Technical Fuel pump buzzing (LPG Conversion) 1.8 16v

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Technical Fuel pump buzzing (LPG Conversion) 1.8 16v


New member
Jun 18, 2021
Hi all,
Just picked up my "new" 2003 Stilo 1.8 16v SW which for its age and the amout of KM on the clock I am very happy with it...

Just a quick question, when I switch from LPG to petrol I have noticed that the fuel pump is continuously buzzing intermittently, I take it that is is not normal.

when starting from petrol the buzzing stops after a few moments.

any ideas?


By "buzzing" I presume you mean you can hear the pump, when you put your head next to it.. not some buzzing under the bonnet/next to the fuel rail, or under the car seat etc.?

A lot of systems (simpler/cheaper ones) leave the fuel pump circuit alone, so that when the LPG is engaged, the fuel pump is still pumping fuel around, even though the car isn't using it. If you have a buzzing fuel pump and the LPG does not interact with it, then it could be a sticky/failing pump.

Your system might be designed to cut the fuel pump when the LPG is engaged, in which case the buzzing may be connected to the LPG system. If it cuts the supply, it may be working through a relay.. and relays can buzz when they're failing... as well as it could be the pump (as above).

Have a look to see if teh LPG has a relay in some place near the pump.

Also check the fuel cut-off switch (by the door pillar) is properly "on" and not half way to becoming "off"... anything that can cause intermittent voltage issues.

Ralf S.
Thanks for the replies, I'm inclined to think it could be a relay as I can only hear the sound from inside the car coming from behind the dashboard, I have noticed that it stops after a few moments then after a while it comes back again...anyway I am going to try and locate and test the relay, fingers crossed it may solve the problem
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