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[tunnie]

I still think that fill up at Morrison's on the way back from the lakes was dodgy.

Crap fuel? Trapped air? 

Usually LPG is fairly consistent 

[feeutfo]

Heavy ends

Poor refining Tilo says, iirc.

[doz]

Trust me Chris if it's off grade it doesn't leave the refinery. Most cock ups are down to the additives put in by the tanker drivers. As they don't add anything to LPG it will be clean and on grade. Good question about the water. If you did manage to get any in the tank you can't exactly get it out but if you do get water intrapped with LPG it would cause a freeze down and block the pipework. So I think you can rule that out.

[Lazydocker]

Trust me Chris if it's off grade it doesn't leave the refinery. Most cock ups are down to the additives put in by the tanker drivers. As they don't add anything to LPG it will be clean and on grade. Good question about the water. If you did manage to get any in the tank you can't exactly get it out but if you do get water intrapped with LPG it would cause a freeze down and block the pipework. So I think you can rule that out.

I know that you know what you're talking about here But I have noticed differences in performance/behaviour (more the latter) between fill ups from, for example, a Supermarket (Generally Autogas/Calor) and Flogas supplied forecourts

Plus there's the continental LPG Surely there are differing amounts of Butane in the propane mix?

[doz]

Nope. No mixing of bute and pane. Honestly the only additive that goes in is Mercaptan for that aroma

[Lazydocker]

Nope. No mixing of bute and pane. Honestly the only additive that goes in is Mercaptan for that aroma

We definitely referring to Autogas... I was led to believe, by some very knowledgeable people, that AG is a Bute/propane mix

[feeutfo]

Hear what your saying Doz, but the injector innards where peppered.

Now, this is the first time I've seen inside an injector block with this many miles on, so that might be normal. 30k. But the carb cleaner has done the trick. It idles. No errors at wot. No stutter top end, and calibrates and maps more responsively, although the pressure was too high before. But it does calibrate and run with better fuel trims at the desired 1.10 bar now.

Fuel trims where +24 and +18 having re set the pressure to 1.10 bar, calibrated again and mapped it the trims are now +16 and +11 and reducing. Teas ready so stopped play. See how the trims are tomorrow evening etc. but its better. Much better.

Needless to say the grumpy stalling didn't occur this evening on the way home at 3c.

[doz]

I'm just wondering if you've got something breaking down inside the lines. Maybe one of the filters or an actual piece of rubber pipe. Still as long as it's ok now. I guess it could of been down to a shitty tank at the filling station. I don't know what checks are carried out at the stations. I'm 99%  sure AG is pure Propane. However I guess there's nothing to stop it being mixed by 3rd parties once it's it's left us. We even have strict procedures for the tankers if they've been carrying mixed loads i.e the previous trip it might of been Butane and now it's Propane. 

[feeutfo]

Could well be something breaking down, but whatever it is, I'll be checking again in a week or so. See if the innards ate clean.


...now, which of the three Mafs I have here is the original one off my car.

[Entwood]

Nope. No mixing of bute and pane. Honestly the only additive that goes in is Mercaptan for that aroma

We definitely referring to Autogas... I was led to believe, by some very knowledgeable people, that AG is a Bute/propane mix

It is .... on the continent .. in UK its Propane only ...   It is this "change" to a Propane/Butane mix and back again 2 weeks later that I'm convinced upsets my 0420/0430 codes. The one thing I can't prove but have been told, is the further south you go the higher the butane element. I've been as far south as the south coast of France and noticed no change in performance and the 0420/0430 did not occur until back in the UK .. exactly as normal..

[doz]

Makes sense. Butane would be to slow to flash in our climate. Serious risk of liquid carry over. However Butane has a lower octane. If your not seeing any performance drop off it just proves we can't get the most out of the Propane.

[Entwood]

Makes sense. Butane would be to slow to flash in our climate. Serious risk of liquid carry over. However Butane has a lower octane. If your not seeing any performance drop off it just proves we can't get the most out of the Propane.

Disagree    We HEAT the liquid phase at the evaporator to get gas for the injectors. Whole purpose of the vap   The system would work without a vap if we all lived on the equator ... problem we have is the liquid gas takes more heat than available from the atmosphere at the rate we consume it .. so we add heat at the vap .. makes absolutely no difference - at the vap - propane or butane.

So, why the difference in gas make up then ?? actually very simple. We don't "pump" liquid gas from the tank to the vaporiser ..it is forced there by the gas pressure above the liquid gas in the tank and the fact that the liquid take off is at the bottom of the tank (invert a bottle of coke and undo the cap !!!)

If we put pure butane in the tank, at temps below 4C there would be no gas pressure above the liquid gas and no fluid would flow to the vap ... the engine would not work (on gas) until the LIQUID IN THE TANK temperature rose above 4C. propane "gases off" to much lower temps (-30 odd I think) so maintains the gas pressure above the liquid to force it to the vap, where engine water temp ensures it becomes gas for the injectors.

The higher the butane content the lower the partial gas pressure at cold temperatures

South of France the temp does not get that low so they can have a higher percentage of butane, but still some propane, to ensure the TANK PRESSURE is always sufficient to move the liquid.

That is my understanding of how it works. ... tin hat fitted for incoming

EDIT :

BTW  the difference between gasoline/propane/butane in calorific value is tiny  ... it is the density that makes most of the difference to how much we burn ..

Heat of Combustion for some common fuels
Fuel            kJ/g       kcal/g    BTU/lb
Hydrogen    141.9   33.9    61,000
Gasoline    47.0      11.3    20,000
Diesel    45.0      10.7    19,300
Ethanol    29.7       7.1    12,000
Propane    49.9      11.9    21,000
Butane    49.2      11.8    21,200
Natural Gas 54.0      13.0    23,000

[Kevin Wood]

Indeed. The only problem with using Butane is that we need the vapour pressure to deliver the liquid to the vapouriser, so a Butane / Propane mix would be OK provided there's enough Propane to give a decent vapour pressure at all times.

[feeutfo]

Ok. This is fixed. Running lovely. Couple of cold starts today. No issues at all.


....although I could put the switch over temp down again, just be really sure. It's currently at 40c.

Cause? IMO. Dodgy fuel from Morrisons, in Leyland. (Sorry Doz)

[feeutfo]

Although, did anyone else fill up there on the way back from the Lakes. ...?