Engine noise help ?

topman · 19th February 2010, 19:11

I've just noticed a noise with my engine. It happens at lower engine speeds, mostly at idle. The noise is like a clock ticking but faster. If anyone had a 1.3 ford engine (endura?) it sounds like this at idle. The noise increases as I increase the revs until about 1600 rpm(ish). It's isn't noticeable during normal driving.

bl52krz · 19th February 2010, 21:13

dont know if i am correct but have heard it said that the fuel evaporator valve makes a ticking noise.

T-Cut · 19th February 2010, 22:45

Yep, I'd say it's the waste fuel vapour recycling system. The solenoid valve taps quite loudly on occasion, usually when the engine's hot and ticking over. I call it the slack tappet simulator. It fools/frightens a lot of owners when heard for the first time. The fuel vapour is pumped from a carbon canister located under the rear end of the car and injected into the inlet system.

TC

topman · 19th February 2010, 23:01

Yep it was after a 60 mile on a NSL road. Where is the vapour taken from the fuel tank? How is it collected into a carbon canister? Is it then pushed/forced into the inlet manifold? Sorry for all the questions I just like to know how these things work.

T-Cut · 20th February 2010, 12:01

The petrol vapour is the gas from the headspace in the tank. As you fill it at the pumps, the gas is displaced. Some may escape at the filler neck, but the rubber seal on the petrol pump should stop most of it, which is directed through a breather pipe into a canister containing active charcoal. The vapour is absorbed. To recycle this, the engine manifold depression draws the vapors in via the recirculation valve (the tappet simulator) to be burned in the engine. This only happens periodically. I've not figured out what circumstances apply. Maybe the ECU trips the system every so many hours (?). Anyway, it seems to happen when the engine's hot and ticking over. If you drive away, the vapour recycling stops.

TC

My quick find marker is #PVR# (Petrol Vapour Recycler)

topman · 20th February 2010, 12:13

Quote:

Originally Posted by T-Cut

The petrol vapour is the gas from the headspace in the tank. As you fill it at the pumps, the gas is displaced. Some may escape at the filler neck, but the rubber seal on the petrol pump should stop most of it, which is directed through a breather pipe into a canister containing active charcoal. The vapour is absorbed. To recycle this, the engine manifold depression draws the vapors in via the recirculation valve (the tappet simulator) to be burned in the engine. This only happens periodically. I've not figured out what circumstances apply. Maybe the ECU trips the system every so many hours (?). Anyway, it seems to happen when the engine's hot and ticking over. If you drive away, the vapour recycling stops.

TC

My quick find marker is #PVR# (Petrol Vapour Recycler)

Thanks for that

, more questions though

When filling up is that what the slits in the neck are for? How would the rec. valve draw petrol vapour from the charcoal? Is it pressure and heat related?

T-Cut · 20th February 2010, 12:19

Quote:

Originally Posted by topman

When filling up is that what the slits in the neck are for?

Oddly I've never examined the petrol filler neck, but there will certainly be a 'vent' hole leading to the canister.

Quote:

How would the rec. valve draw petrol vapour from the charcoal? Is it pressure and heat related?

The valve doesn't draw the fumes, the manifold depression causes a pressure drop between the canister and the engine. The vapour simply desorbs from the charcoal. It's a very weak attraction. I think the solenoid valve lets it through in pulses, Why I've no idea.

TC

crownwheel · 31st March 2011, 17:57

Just developed STS in the last two days. Coincidentally the car (V6) was just converted to LPG a week ago so it is suspicious that this noise has just started.
Only slightly noticeable outside / inside car but a fair rattle under the bonnet. If this is associated with fuel (petrol) return why would it happen when idling on LPG? Don't have a diagram or operating manual for the conversion so I am right out of guesses.
Have read associated threads but am out of ideas.
Suggestions welcome
John

19th February 2010, 19:11	#1
topman This is my second home MG ZT-T 190 Join Date: Jun 2009 Location: Lincolnshire Posts: 5,493 Thanks: 372 Thanked 647 Times in 534 Posts	Engine noise help ? I've just noticed a noise with my engine. It happens at lower engine speeds, mostly at idle. The noise is like a clock ticking but faster. If anyone had a 1.3 ford engine (endura?) it sounds like this at idle. The noise increases as I increase the revs until about 1600 rpm(ish). It's isn't noticeable during normal driving. Last edited by topman; 19th February 2010 at 19:22..

19th February 2010, 21:13	#2
bl52krz This is my second home Rover 75 cdt club + Rover 2.5 KV6 Conni SE Join Date: May 2008 Location: Birmingham Posts: 11,424 Thanks: 6,587 Thanked 2,262 Times in 1,729 Posts	dont know if i am correct but have heard it said that the fuel evaporator valve makes a ticking noise. __________________ Great Barr, Birmingham.

20th February 2010, 12:01	#5
T-Cut This is my second home Rover75 and Mreg Corsa. Join Date: Nov 2006 Location: Sumweer onat mote o'dust (Sagin) Posts: 21,754 Thanks: 341 Thanked 3,660 Times in 2,924 Posts	The petrol vapour is the gas from the headspace in the tank. As you fill it at the pumps, the gas is displaced. Some may escape at the filler neck, but the rubber seal on the petrol pump should stop most of it, which is directed through a breather pipe into a canister containing active charcoal. The vapour is absorbed. To recycle this, the engine manifold depression draws the vapors in via the recirculation valve (the tappet simulator) to be burned in the engine. This only happens periodically. I've not figured out what circumstances apply. Maybe the ECU trips the system every so many hours (?). Anyway, it seems to happen when the engine's hot and ticking over. If you drive away, the vapour recycling stops. TC My quick find marker is #PVR# (Petrol Vapour Recycler) Last edited by T-Cut; 20th February 2010 at 12:07..

19th February 2010, 22:45	#3
T-Cut This is my second home Rover75 and Mreg Corsa. Join Date: Nov 2006 Location: Sumweer onat mote o'dust (Sagin) Posts: 21,754 Thanks: 341 Thanked 3,660 Times in 2,924 Posts	Yep, I'd say it's the waste fuel vapour recycling system. The solenoid valve taps quite loudly on occasion, usually when the engine's hot and ticking over. I call it the slack tappet simulator. It fools/frightens a lot of owners when heard for the first time. The fuel vapour is pumped from a carbon canister located under the rear end of the car and injected into the inlet system. TC

19th February 2010, 23:01	#4
topman This is my second home MG ZT-T 190 Join Date: Jun 2009 Location: Lincolnshire Posts: 5,493 Thanks: 372 Thanked 647 Times in 534 Posts	Yep it was after a 60 mile on a NSL road. Where is the vapour taken from the fuel tank? How is it collected into a carbon canister? Is it then pushed/forced into the inlet manifold? Sorry for all the questions I just like to know how these things work.

31st March 2011, 17:57	#8
crownwheel Newbie rover 75 cdti saloon & V6(LPG) Join Date: Sep 2010 Location: newmilns Posts: 8 Thanks: 0 Thanked 0 Times in 0 Posts	Just developed STS in the last two days. Coincidentally the car (V6) was just converted to LPG a week ago so it is suspicious that this noise has just started. Only slightly noticeable outside / inside car but a fair rattle under the bonnet. If this is associated with fuel (petrol) return why would it happen when idling on LPG? Don't have a diagram or operating manual for the conversion so I am right out of guesses. Have read associated threads but am out of ideas. Suggestions welcome John