Stalling Bi-fuels

[Bry_fuel]

I thought I'd let all the irritated 'stalling Bi-fuel' owners know that I've fixed mine.

It's a 2003 V70 Bi-fuel that's done 92,000m

Symptom:
Stalling at junctions and on motorways; as though a gremlin has switched the gas off.

Cure:
Changed the stepper motor on the gas distributor.

Downside:
It cost me £340 for the motor with VOC discount and vat. I'm sure it must be only worth £50. There must be a cost effective source somewhere?

Upside:

It only took a couple of hours to change and is quite simple. Mine does have jubilee clips on the distributor, due to early warranty work, which probably makes it easier.

How:

Find a competent person. You don't want any gas leaks in the engine bay.

With the car running on gas disconnect the solenoid cable under the air box to purge the system of gas. Reconnect before you forget.

Disconnect battery. The distributor is close to some chunky cables that can supply lots of amps if you put a spanner in the wrong place!

Clamp the lower power steering hose near the pump and disconnect the top hose and move out of the way. (Don't get oil in the alternator) Unbolt the dip stick pipe. You don't have to remove it but it is easier if you do. Remove the pipes and cables and undo the 2 nuts on the distributor / engine bracket. I found leaving the bracket on the distributor easiest. Remove; some jiggling required.

Make sure the outside of the stepper motor is clean, remove 2 screws and remove motor. Unclip piston from spring (note which way up it goes). Remove spring and assemble on new motor.

If the car was a bit lumpy on gas the distributor it probably needs the slots cleaning. Probably best to get the service kit and change all the rubbery bits if doing this. There is a recommended Volvo silcone grease for the piston. I used Marley plastic pipe grease; worked Ok previously when I cleaned it. I think almost none is required otherwise it will fill the slots.

Make sure it is spotlessly clean before reassembly.

Put it back together and check for leaks.


It hasn't stalled for 2 days and no longer stutters when switching to gas on tick over.

I hope it lasts and helps all other annoyed Bi-fuel owners.

Bryan

[PJPJ]

Stappermotor EGI+MEGA
Art.Nr.: NE238001-011

Stappermotor EGI+MEGA
Ab 74,97 EUR
Lieferzeit:
3-4 Tage
1 x 'Stappermotor EGI+MEGA' bestellen

Steppermotor DGC
Art.Nr.: AG258150


Ab 102,89 EUR
Lieferzeit:
3-4 Tage
1 x 'Steppermotor DGC' bestellen


Steppermotor Necam Venturi
Art.Nr.: NE238000-090

Steppermotor Necam Venturi
Ab 59,10 EUR
Lieferzeit:
3-4 Tage
1 x 'Steppermotor Necam Venturi' bestellen

DGC Steppermotor
Art.Nr.: AG258155


Ab 92,89 EUR
Lieferzeit:
3-4 Tage
1 x 'DGC Steppermotor' bestellen

Maybe one of these would have been suitable. Do any of the numbers match?

Best Regards

PJPJ

[birdseye]

you obviously have some knowledge of the gas system. I'm a reasonable general mechanic and have happily stripped down both engines and gearboxes. but I dont understand the gas system and so far havent gone near it.

how does it work? can you tell me the components in the system and what they do from the tank to the engine. for example, the gas distributor presumably distributes gas but is it timed like an ignition distributor? does it allow gas into one cylinder at a precisely timed point?

and what about filters and pumps? where are they? what can you disconnect without letting all the gas out of the tank?

help! I need educating - and incidentally I have just the problem you descibe above and a dealer who is both expensive and useless.

[Clan]

no dealers around usk , do you go to cardiff , gloucester , bristol or abergavenny?

[birdseye]

nearest dealer is abergavenny. small outfit so you can imagine how often they see a bi-fuel. and very expensive, like twice the servicing cost of my previous BMW

so its got to be a bit of DIY if someone will explain the basic principles / componentrs of the gas system. I've happily stripped gas boilers before but they are easy to understand.

[PJPJ]

Hi,

If you look here, these are the basic components for the Koltec system. Look at the EGI drawing. I think, that may be closer to your type of system and you will have the EGI distributor. The Volvo has an integrated LPG and standard ECU rather than seperate units for each fuel. The diagnostics test does not work for the Volvo's.

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

This site is a good place to start. More applicable from halfway down the page.

http://www.juliantrubin.com/encyclop...ering/lpg.html

I'll P.M. you a link on how to clean your EGI distributor, if you have one of this type.

Best Regards

PJPJ

[Bry_fuel]

Originally Posted by birdseye

you obviously have some knowledge of the gas system. I'm a reasonable general mechanic and have happily stripped down both engines and gearboxes. but I dont understand the gas system and so far havent gone near it.

how does it work? can you tell me the components in the system and what they do from the tank to the engine. for example, the gas distributor presumably distributes gas but is it timed like an ignition distributor? does it allow gas into one cylinder at a precisely timed point?

and what about filters and pumps? where are they? what can you disconnect without letting all the gas out of the tank?

help! I need educating - and incidentally I have just the problem you descibe above and a dealer who is both expensive and useless.

Update:

Just got back from a week in France (slightly longer than I was expecting due to some problem with cod; and of course not allowed on that expensive train!) but it has not stalled once - one cured Volvo.

I think the stepper motor just regulates the amount of gas by moving a piston up and down; the amount being governed by the slots in the distributor. I am a bit confused how the system distributes it to each cylinder; it appears they are all supplied simultaneously.

There are two solenoid valves; one on the tank with a connector in the boot to allow it to be isolated and another under the air box. If you disconnect the boot connector with the engine running it will purge the gas in the pipes form the tank to the distibutor. If you disconnect the connector on the valve under the air box it will just purge the vapouriser and distributor.

The only numbers on the old motor and 8623R004 and 1473. Don't seem to match the numbers on the other post. It is Swiss made. I may try and dismantle it to see if there are any more numbers under plastic connector.

[volvolvo]

after the second day from purchase the Volvo suddenly cut out which was a shock but ok as we were on a side road and not the fast lane of the M6!!
The basics of the system.
Typical the Volvo Bi fuels have a rear gas tank with shut off solenoid.
Pipe to the front engine bay to another shut off solenoid
Feed to the pressure reducer / Vapouriser which compensates for manifold pressure acceleration etc and provided gas at the right pressure to the necam distributor. The distributor is itself controlled by a Volvo Type B stepper motor.
After eliminating the rear isolator valve which was allowing gas to the front when active and isolated before working on the car by disconnecting the battery) then by replacement other components such as the engine cut off solenoid which had been botched, the vapouriser that was leaking LPG and the distributor body (which I cleaned with solvent and compressed air and serviced with an overhaul kit, -- note the distributor body and piston are machine matched to very fine tolerances less than 0.001 thou and must not be damaged or mixed and matched with other parts) only one component was left. Yes the expensive £300 stepper motor. After replacement we have had no further incidents of stoppage after nearly a month of driving in all weathers. All gas joints I tested with soapy water for leaks before commissioning.
Disclaimer Please NOTE LPG is a highly inflammable gas and this posting is for information only and to help save you time and not intended as a workshop manual so take you Volvo to a registered LPG agent is recommended.
I Searched Google for information on stripping the vapouriser and distributor as its all out there thanks to Polish websites that are second to none in being helpful

[CNGBiFuel]

I do stepper motors for half what you paid. And with my mod, comes better than new.
The stepper is the weak link and without cleaning, lubing and my cooling mod have short lives. OK for a £40 item, but these are nearer £350. The Type A version was only fitted to some CNG versions and Vauxhalls, Opels and Transits, you can get those for £40 odd, but they'll not fit most.

Necam/Koltec are aware of the issues and must be aware of my mod, it's a simple thyristor change.
The Necam system gets maligned for this weak-link.

CNG is the 'Gas of the Gods'. If you've LPG over CNG, LPG is dirty stuff so keep it clean or munch another stepper.

Can I have your old stepper? I'll pay £30.

[Joe Harding]

Originally Posted by birdseye

nearest dealer is abergavenny. small outfit so you can imagine how often they see a bi-fuel. and very expensive, like twice the servicing cost of my previous BMW

so its got to be a bit of DIY if someone will explain the basic principles / componentrs of the gas system. I've happily stripped gas boilers before but they are easy to understand.

Is John Rage still operating in Monmouth? He used to do LPG