S40 only idles on LPG

radebe2k · Feb 20th, 2009, 15:59

Had this sudden problem today after stopping at a clients workplace, was running fine up untill that point (10 mile trip, from warm) no hiccups, stalls anything untoward, had already done an 80 mile trek that day and 2 others on previous days with no incident at all.

Tried to pull away after finishing work, engine idling fine but would not rev at all on lpg, foot fully or slightly down woul make the engin reve between 800 and 1k rpm but that was it, switch to petrol and all was well, didnt cut out when switching back to lpg just no power and no rev above 1k.

Have got a volvo (st)dealer in my area but loathed to go there because on a full service then missed a snapped rear coil spring so have very little faith in their abilities but i may be able to take advantage and get some free work done.

Any thoughts? everyone is suggesting filters but i had the car fully serviced less than a year ago with filter changes (mind you this was at the stealers so you never can fully tell by just a tick in the box on the report)

i'm goign to try "turning it off and on again" as i'm in the IT industry by taking the battery off and see if that resets anything, but any other ideas about things i could try or where i can get filters from would be most appreciated.

UPDATE.....

engine immediately dies when swtching to lpg, not even a cough or splutter just instant death even at higher rpm, could an issue like this come up so quickly even if it's a clogged filter, ie no gradual loss of power, just all there then nowt?

davew · Feb 21st, 2009, 01:38

I would probably agree with the filters.

You say the car was serviced less than a year ago? was this the same garage that missed the spring?

Maybe they change the obvious filters, but missed the lpg ones?

LPG really does need changing every 12000 miles.

And yes any pipe can become blocked quickly. Think about it... its a pipe, if something bigger than the diameter wants to get down it, it will get stuck.

Mike B · Feb 21st, 2009, 10:07

Quote:

Originally Posted by davew

I would probably agree with the filters.

You say the car was serviced less than a year ago? was this the same garage that missed the spring?

Maybe they change the obvious filters, but missed the lpg ones?

LPG really does need changing every 12000 miles.

And yes any pipe can become blocked quickly. Think about it... its a pipe, if something bigger than the diameter wants to get down it, it will get stuck.

Hi
I know this sounds daft, but you have GAS the symtoms sugest you have run out , you might have some in the tank but if the cut off valve for example is stuck ? or the tank valve may be turned too far off .
I know these seem silly but over 40 years with gas , I have come across all of these , and easy to check.
Regards
Mike B

radebe2k · Mar 4th, 2009, 17:11

definately not run out, filled to the brim before the last good gas run so no worries there.

are there any good resources on the interweb so i can see where i could be looking, i hear a click from the rear when i try the lpg so i sounds like somethign is happening but completely in the dark about where the filters are, how to change them, where the valves are and how to check the operation, haynes doesnt cover lpg in the s40 manual, unless there is a specific version, also any reputable factors place i can get parts from, i see the GSF (German Swedish French) motor factors vans around the place, are they any good? I'm no mechanic but as i trouble shoot pc's all day long a simple beast like an IC engine isn't that daunting, especially if it still works-ish.

The stealers found a knock sensor fault (probably from stalling) and reset it and that seemed to make a difference in the fact that it would idle again and not cut straight out but i stalled it and it wont run on gas again now. hey did say they woudl liek the car for 2 days to diagnose, i guess that would allow me to start the process of re-mortgaging the house to pay for the bill.

According to the service report the filters were changed. the service was a big 90k ish one which would have meant the cam belt change but that was done not long before i bought the car so in all respects it was a big service without the big bit.

capt jack · Mar 4th, 2009, 21:48

Assuming a factory fit works much as an aftermarket system, the click from the rear is the valve on the tank opening up and pressurising the lpg system.

This suggests that this much is working OK.

When you start the car on petrol, the lpg system is not pressurised. After running for a short time on petrol the lpg tank valve opens to pressurise the lpg system, then once the pre-set engine temp is reached, the lpg pressure regulator opens up to let lpg through to the lpg injectors. At the same time the ECU recognises the lpg and tells the petrol side of things to stop functioning.

What should happen is that if the gas supply runs out the ECU should switch straight back to petrol. From what you describe it sounds as though this isn't happening. This suggests the ECU is being fooled into thinking that the LPG system is OK. Could be something as silly as a loose wire!

The lpg regulator (sometimes called lpg distributor - not to be confused with the ignition bit of the same name!) regulates the pressure and by means of hot coolant diverted from the radiator vapourises the lpg so that it goes to the lpg injectors in gaseous form. If the lpg doesn't warm up enough the system won't work properly. As I understand it, these regulator/distributors vary from make to make, but all perform basically the same function. I reckon your regulator might be dying / defunct, and that because of the way in which the whole set-up is configured, the problem is effectively down-stream of the point at which the ECU registers the supply or otherwise of LPG.

You need to get the car to a good LPG specialist. The LPGA accredited people in Portsmouth are:

Hants Auto Fuels Ltd
Unit 5/6,
Hammond Industrial Park,
Stubbington Lane,
Hants,
Fareham,
PO14 2PT,

Approval Date:
09-Nov-04

Phone Number:
01329 667788

Fax Number:
01329 661166

Email:
enquiries@hantsautofuels.co.uk

Website:
www.hantsautofuels.co.uk

Problem with main stealers is that they don't see many LPG cars, and anyway are only really interested in newish ones where the (company) owners are happy to pay through the nose for servicing - which often amounts to nothing more than to change the oil and count the wheels.

I'm sure it can be sorted - just needs attention from a real LPG expert.

Cheers

Jack

PJPJ · Mar 5th, 2009, 19:41

Hi,

It sounds like the stepper motor has packed in.

This is located on the top of the distributor. It moves a plunger up and down inside the distributor in relation to the position of the accelerator pedal. (i.e. gives more gas if you want to go faster.

It is possible the plunger is jammed inside.

Lubricate it with teflon spray only.

This is assuming you have this type of distributor on your factory fit. Most Volvo factory fits have.

Best Regards

PJPJ

radebe2k · Mar 5th, 2009, 20:05

will give it a go, funny though that it's the throttle that might be screwey, was the same in the Astra we have (non lpg) as it has an electronic throttle and that woudlnt idle woudl rev fine but no idle just dies, was a nightmare stuck in traffic on a hill trying to balance the throttle, brake and clutch, needed an extra led and stopping the car on the handbrake. at least this beastie still runs, albeit on the expensive jungle juice.

no specific teflon spray brand?, if not i guess halfords cycle stuff would do the trick as it says it leaves teflon behind

PJPJ · Mar 5th, 2009, 22:17

Hi,

The reason for PTFE (Sorry, Teflon is a brand) spray is because it's a plastic plunger.

The Ambersil here looks the best on this page. But the choice is yours.

http://cpc.farnell.com/jsp/search/br...&Ntt=ptfe&Ntx=

It isn't the throttle itself that I'm saying is the problem. It's the stepper motor on the LPG distributor. It is the black bit at the top on the EGI Koltec/ Necam Distributor here. Do not spray PTFE on your throttle controller.

http://www.my90.co.uk/lpg/album_pers...hp?user_id=500

Click on comments to read a description.

I've sent you one private message too.

Best Regards

PJPJ

radebe2k · Mar 6th, 2009, 09:03

righto, going to take a look today as i am having visions of pound coins coming out the tailpipe when running at the moment!

radebe2k · Mar 8th, 2009, 09:44

took it on a run down to DorsetLPG who has the Volvo software, he hd a butchers and it was the regulator\meter that was screwed, serviced it and all is well now.

it was the part you suggested PJPJ earlier, the aluminium muffin as i've now christened it. and i did have a look myself, took the motor off and found the plunger stuck half way down but what chris said at Dorset was it was screwed anyway.

Will be going back there for a full service on the system as volvo seem to have their own definitions of Full Service, i think i means their pockets are full with my cash!.

Feb 20th, 2009, 15:59	#1
radebe2k New Member Last Online: May 1st, 2009 07:29 Join Date: Feb 2009 Location: portsmouth	S40 only idles on LPG Had this sudden problem today after stopping at a clients workplace, was running fine up untill that point (10 mile trip, from warm) no hiccups, stalls anything untoward, had already done an 80 mile trek that day and 2 others on previous days with no incident at all. Tried to pull away after finishing work, engine idling fine but would not rev at all on lpg, foot fully or slightly down woul make the engin reve between 800 and 1k rpm but that was it, switch to petrol and all was well, didnt cut out when switching back to lpg just no power and no rev above 1k. Have got a volvo (st)dealer in my area but loathed to go there because on a full service then missed a snapped rear coil spring so have very little faith in their abilities but i may be able to take advantage and get some free work done. Any thoughts? everyone is suggesting filters but i had the car fully serviced less than a year ago with filter changes (mind you this was at the stealers so you never can fully tell by just a tick in the box on the report) i'm goign to try "turning it off and on again" as i'm in the IT industry by taking the battery off and see if that resets anything, but any other ideas about things i could try or where i can get filters from would be most appreciated. UPDATE..... engine immediately dies when swtching to lpg, not even a cough or splutter just instant death even at higher rpm, could an issue like this come up so quickly even if it's a clogged filter, ie no gradual loss of power, just all there then nowt? Last edited by radebe2k; Feb 20th, 2009 at 16:10. Reason: Updated Information & poor spelling

Feb 21st, 2009, 01:38	#2
davew Senior Member Last Online: Jun 16th, 2011 15:27 Join Date: Sep 2008 Location: Nelson	I would probably agree with the filters. You say the car was serviced less than a year ago? was this the same garage that missed the spring? Maybe they change the obvious filters, but missed the lpg ones? LPG really does need changing every 12000 miles. And yes any pipe can become blocked quickly. Think about it... its a pipe, if something bigger than the diameter wants to get down it, it will get stuck. __________________ S80 - 301 Bhp - 450Nm

Mar 5th, 2009, 20:05	#7
radebe2k New Member Last Online: May 1st, 2009 07:29 Join Date: Feb 2009 Location: portsmouth	will give it a go, funny though that it's the throttle that might be screwey, was the same in the Astra we have (non lpg) as it has an electronic throttle and that woudlnt idle woudl rev fine but no idle just dies, was a nightmare stuck in traffic on a hill trying to balance the throttle, brake and clutch, needed an extra led and stopping the car on the handbrake. at least this beastie still runs, albeit on the expensive jungle juice. no specific teflon spray brand?, if not i guess halfords cycle stuff would do the trick as it says it leaves teflon behind Last edited by radebe2k; Mar 5th, 2009 at 20:12. Reason: additional info

Mar 4th, 2009, 17:11	#4
radebe2k New Member Last Online: May 1st, 2009 07:29 Join Date: Feb 2009 Location: portsmouth	definately not run out, filled to the brim before the last good gas run so no worries there. are there any good resources on the interweb so i can see where i could be looking, i hear a click from the rear when i try the lpg so i sounds like somethign is happening but completely in the dark about where the filters are, how to change them, where the valves are and how to check the operation, haynes doesnt cover lpg in the s40 manual, unless there is a specific version, also any reputable factors place i can get parts from, i see the GSF (German Swedish French) motor factors vans around the place, are they any good? I'm no mechanic but as i trouble shoot pc's all day long a simple beast like an IC engine isn't that daunting, especially if it still works-ish. The stealers found a knock sensor fault (probably from stalling) and reset it and that seemed to make a difference in the fact that it would idle again and not cut straight out but i stalled it and it wont run on gas again now. hey did say they woudl liek the car for 2 days to diagnose, i guess that would allow me to start the process of re-mortgaging the house to pay for the bill. According to the service report the filters were changed. the service was a big 90k ish one which would have meant the cam belt change but that was done not long before i bought the car so in all respects it was a big service without the big bit.

Mar 4th, 2009, 21:48	#5
capt jack VOC Member Last Online: Yesterday 22:32 Join Date: Jun 2006 Location: Selby, North Yorkshire	Assuming a factory fit works much as an aftermarket system, the click from the rear is the valve on the tank opening up and pressurising the lpg system. This suggests that this much is working OK. When you start the car on petrol, the lpg system is not pressurised. After running for a short time on petrol the lpg tank valve opens to pressurise the lpg system, then once the pre-set engine temp is reached, the lpg pressure regulator opens up to let lpg through to the lpg injectors. At the same time the ECU recognises the lpg and tells the petrol side of things to stop functioning. What should happen is that if the gas supply runs out the ECU should switch straight back to petrol. From what you describe it sounds as though this isn't happening. This suggests the ECU is being fooled into thinking that the LPG system is OK. Could be something as silly as a loose wire! The lpg regulator (sometimes called lpg distributor - not to be confused with the ignition bit of the same name!) regulates the pressure and by means of hot coolant diverted from the radiator vapourises the lpg so that it goes to the lpg injectors in gaseous form. If the lpg doesn't warm up enough the system won't work properly. As I understand it, these regulator/distributors vary from make to make, but all perform basically the same function. I reckon your regulator might be dying / defunct, and that because of the way in which the whole set-up is configured, the problem is effectively down-stream of the point at which the ECU registers the supply or otherwise of LPG. You need to get the car to a good LPG specialist. The LPGA accredited people in Portsmouth are: Hants Auto Fuels Ltd Unit 5/6, Hammond Industrial Park, Stubbington Lane, Hants, Fareham, PO14 2PT, Approval Date: 09-Nov-04 Phone Number: 01329 667788 Fax Number: 01329 661166 Email: enquiries@hantsautofuels.co.uk Website: www.hantsautofuels.co.uk Problem with main stealers is that they don't see many LPG cars, and anyway are only really interested in newish ones where the (company) owners are happy to pay through the nose for servicing - which often amounts to nothing more than to change the oil and count the wheels. I'm sure it can be sorted - just needs attention from a real LPG expert. Cheers Jack

Mar 5th, 2009, 19:41	#6
PJPJ New Member Last Online: Apr 23rd, 2011 01:01 Join Date: Jan 2009 Location: Huddersfield	Hi, It sounds like the stepper motor has packed in. This is located on the top of the distributor. It moves a plunger up and down inside the distributor in relation to the position of the accelerator pedal. (i.e. gives more gas if you want to go faster. It is possible the plunger is jammed inside. Lubricate it with teflon spray only. This is assuming you have this type of distributor on your factory fit. Most Volvo factory fits have. Best Regards PJPJ

Mar 5th, 2009, 22:17	#8
PJPJ New Member Last Online: Apr 23rd, 2011 01:01 Join Date: Jan 2009 Location: Huddersfield	Hi, The reason for PTFE (Sorry, Teflon is a brand) spray is because it's a plastic plunger. The Ambersil here looks the best on this page. But the choice is yours. http://cpc.farnell.com/jsp/search/br...&Ntt=ptfe&Ntx= It isn't the throttle itself that I'm saying is the problem. It's the stepper motor on the LPG distributor. It is the black bit at the top on the EGI Koltec/ Necam Distributor here. Do not spray PTFE on your throttle controller. http://www.my90.co.uk/lpg/album_pers...hp?user_id=500 Click on comments to read a description. I've sent you one private message too. Best Regards PJPJ

Mar 6th, 2009, 09:03	#9
radebe2k New Member Last Online: May 1st, 2009 07:29 Join Date: Feb 2009 Location: portsmouth	righto, going to take a look today as i am having visions of pound coins coming out the tailpipe when running at the moment!

Mar 8th, 2009, 09:44	#10
radebe2k New Member Last Online: May 1st, 2009 07:29 Join Date: Feb 2009 Location: portsmouth	took it on a run down to DorsetLPG who has the Volvo software, he hd a butchers and it was the regulator\meter that was screwed, serviced it and all is well now. it was the part you suggested PJPJ earlier, the aluminium muffin as i've now christened it. and i did have a look myself, took the motor off and found the plunger stuck half way down but what chris said at Dorset was it was screwed anyway. Will be going back there for a full service on the system as volvo seem to have their own definitions of Full Service, i think i means their pockets are full with my cash!.

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