S80 bifuel - now refuses to run on LPG

[cjr]

Hewey. Thanks for the above note. My s80 Bi fuel had been running ok, except the stalling and forced to switch to petrol. I recently used the forementioned injector fluid cleaning method. Now the car will generally run on lpg for ten miles then stuttering occurs and forced to switch to petrol. If I attempt to switch back the engine slowly dies and iam unable to accelerate. I would be keen to revamp distribtor but concerned at difficulty. Do you have any images or further advice ? I will talk to Volvo about kit & membrane

[cjr]

by the way there does not appear to be any photos on this link.... did anybody save copies...


http://www.volvo-forum.nl/viewtopic.php?t=2398

[MrP]

i get pics when i look at that link.

dosent mean much to me though

[cjr]

Can view photos today... but all Dutch to me

[Hewey]

If you look at the last picture, you see on the left the distributor turned upside down and on the right side is the bottom plate (not turned upside down). The plate attaches to the distributor with 3 little hex bolts. In the picture, you cannot see it properly, but there is a spring under the membrane (veer in dutch), which presses the membrane against the big opening in the center of the distributor. You can see the small O-ring sealing the DFCO-route. Gas should be able to flow to the big opening but if the membrane has molten somewhat and sticks on the big opening, the gas will not flow. So clean the big opening and renew the molten membrane. If it is the case.

The distributor seems to be in a tight spot in the newer Volvos, so it could be a hard work to even reach the distributor.

Could you please repeat the circumstances when the motor has problems? Does it stall on gas drive only after motorbraking, or does it also stall from stable driving? There could be lots of other issues too on your system, but if the stalling only happens after motorbraking, it would be logical that the fault is related to the DFCO-valve/membrane area.

Regards, Hewey

P.S. I wrote previously an inaccurate description of how the DFCO-system works and somehow can't edit that post anymore. It's not a big deal, it's just that when the little route (call it pilot or DFCO-route or what ever) is open, the gas pressure will also go under the membrane, and with the spring load it will cause the membrane to shut the main gas flow. And when the little route is then closed, there is no gas pressure to aid the spring and the main gas flow pressure on the other side of the membrane will force the spring to bend and open the membrane away from the big opening.

[cjr]

Hewey. The car runs on gas for 6 to 30 miles before stuttering and either auto switching or I have to overide and turn off the gas. The car will stall when running on gas if braking takes place. In both instances when attempting to manually switch back the car it will either continue with stuttering or will switch and I assume the engine management restricts increases the revs/speed. The car has new spark plugs, and gas inline filter, and is due an oil change.

The distributor is in an awkward position to work, however if the only wires/hoses attached are gas in, 5 gas out (?) and one electrical, as a amature I would be happy to give it ago...

In your experience does the distributor get dirty or just the repairable bits become tired ?

[Hewey]

It seems that somehow the motor runs short of gas after a while, it could be the membrane or something else too. In case you decide to open the distributor, you can also get the distributor repair set from here (www.lpg-kits.org.uk), the package (Necam distributor repair kit) is more complete than the one Volvo sells and propably cheaper too.

Yes the distributor has those 1 big input, 5 little output pipes plus the wirings for stepper motor and for DFCO-valve.

I had some dirt in the V-grooves but the sliding cylinder was moving nicely. The membrane was ok, I did not have stalling issues but changed it anyway to be sure.

If the fault should not be in the distributor, another possibility is the gas pressure regulator/vaporiser. Who knows, the regulator/vaporiser might not work correctly after a while of gas driving.

You can check if the regulator/vaporiser has leaking membranes by taking the vacuum line off from the intake manifold, blocking the manifold hole, and putting the loose end of the vacuum pipe to a glass of water. If the membranes leak, you'll see bubbles in the water.

Have you checked from your gas pressure regulator/vaporiser coolant pipes that the heat circulation works ok? You should be able to feel that one coolant pipe is hotter and the other cooler, as the vaporising gas draws heat from the coolant.

And also, have you checked that regulator adjusts the gas pressure to correct level?

Regards, Hewey

[duncan_ellison]

I'm glad to see that there's still an active thread on this subject.

I too have had the multiple arguements with Volvo and am now on my fourth gas distributor, but I've come to recognise that a stuck up gas distributor usually manifests itself as poor performance or stuttering under load. This usually responds to the throtttle cleaner trick and I go back to sleep for another 10K miles.

However .... I've now got the exact same symptoms as CJR. 4 - 10 miles max. and the engine just dies.

No warning, total loss of servo assist etc. It's pretty dangerous and Volvo should be ashamed of itself for brushing these issues under the carpet, no wonder they silently dropped the Bi-Fuel from the range.

This one is driving me nuts. I've serviced the Gas Distributor and the Vaporiser. At 130K, the membranes in the Vaporiser were getting a bit porous, but that didn't actuallyfix the problem.

I've started to investigate other potential issues now. It seems to me that this only occurs when the engine warms up to a certain level. I replaced the water thermostat, but that didn't help.

These models are also infamous with throttle body (TPS) sensor issues, so I cleaned it out best I could and I did seem to get a little further after that, but it could just be coincidence.

The genuine Necam systems have a fault code readout which is fairly easy to get to, but Volvo seems to have hidden this in its ECU somewhere.

If anyone else gets traction on this problem, please let us know. I love my V70 (sixth in a row), but this is really putting me off buying another.

Duncan

[Clan]

Have you checked the LPG inlet pipe to the evaporator / governor ? There is a valve on the end inside which a lever operates it slides up and down on the end of the brass union which screws into the casing and sometimes sticks on high mileage units ... some scotchbrite soon cleans it up ...

[duncan_ellison]

cjr, Did you get any further with your LPG problems, your symptoms sound exactly like mine.

I've replaced distributor / evaporator / fuel shut off solenoid / evaporator solenoid/ stepper motor with either known good or new parts.

Checked tank solenoid (seems OK), checked tank sender (odd 12.5 - 347 Ohm reading, thought they should be 0 -90 Ohms but showing OK on the gauge).

Tank and Evap. solenoid both make a solid clunk when activated.

Fault code reader shows no faults associated with the powertrain, just a persistent one with the CCM (Climate Control Module).

Just had it running in idle for over an hour, but immediately prior to that would not run for more than 7 miles without cutting out.

Starting to very very annoyed with this now :-(

Duncan