Bad petrol

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Mon 5 Dec 2011 19:30
Bad petrol - Bobbin Threadbare

I think I've had a duff batch of petrol. Fuel economy is rubbish this last tankful, and the emissions stink! I had a little panic that my catalytic converter was on the blink but I reckon that's supposed to smell like bad eggs.

Blinking Texaco as well!! I shall go back to Asda (or make the extra effort to go to Shell)!

Anyone else had any muck off Texaco lately?

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Tue 6 Dec 2011 08:26
Bad petrol - TeeCee

I don't think that making a point of going elsewhere is necessarily a solution.

Over the years I have had two tankfulls of crud, both from Shell. Yet that's two out of god-alone-knows-how-many times I have filled up at a Shell station.

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Tue 6 Dec 2011 20:13
Bad petrol - boggles

Having seen the cacky deposits that can build up, in a relatively short time, in the bottom of a fuel bulk tank. I think a lot of problems with "bad fuel" occur when you fill up shortly after a delivery has been made, and the crud is still swirling about.

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Wed 7 Dec 2011 00:10
Bad petrol - unthrottled

(back after a short hiatus).

I've never had a duff tankful of petrol and I don't know anyone who has. Then again I (and most of my friends) will buy the cheapest swill going. The cheapest swill going tends to have a high turnover and doesn't spend long in the tanks. Petrol does have a finite shelf life, and I bet that the ordinary unleaded will be in much better condition than the 'super' stuff which sells aout five gallons a fortnight.

The liability costs of selling contaminated fuel are so high that it happens very, very rarely. If the fuel is bad, there'll be a spate of affected cars in the area.

(I bought a tank of Texaco fuel about a fortnight ago and it was just as good as Asda smart price :)

btw-how's the PGCE going Bobbin?

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Wed 7 Dec 2011 08:30
Bad petrol - TeeCee

You're probably on the money there unthrottled.

Both the duff tanks I had were from rural stations well off the beaten track that probably had low turnover.

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Wed 7 Dec 2011 10:55
Bad petrol - AlleyCat`

The fuel economy from my last tank of fuel dropped off quite a lot (about 5mpg over a full tank).

I put it down to a possiblity they have changed the fuel additives for the colder weather and the car not running as well on it (I might be making up that they do this?).

Or it could be just the car isn't running as well in the cold (diesel in my case).

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Wed 7 Dec 2011 11:18
Bad petrol - unthrottled

They change the actual composition of both petrol and diesel in the winter which has a slightly lower calorific value. The colder weather will have a bigger impact though, especially on short journeys. Motorway commuters probably won't see a large drop in consumption during winter. There'll a bit from winter diesel, denser air and higher rolling resistance though.

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Wed 7 Dec 2011 09:38
Bad petrol - unthrottled

Wouldn't the pumps have filters to collect the debris? That's not a rhetorical question, I don't know!

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Wed 7 Dec 2011 10:00
Bad petrol - Armitage Shanks {p}

Don't car fuel systems have fiters to sort out crud too? Obviously no use if there is is enough junk to block the filter natch!

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Wed 7 Dec 2011 11:22
Bad petrol - Armitage Shanks {p}

To expand on my statement of the blimmin obvious - crud shouldn't get into the engine due to filters at the supplying pump and in the car fuel system BUT the latter might get blocked enough to reduce the supply to the engine and to cause rough running

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Wed 7 Dec 2011 11:55
Bad petrol - unthrottled

But wouldn't that only cause rough running at times of high fuel demand? Idle and cruising shouldn't be affected

The thing is, you can make wild changes to the fuel (like substituting petrol for methanol, ethanol, propane, natural gas etc) and if get mixture about right, you wouldn't notice much, if any difference in the way the engine ran.

Bad petrol is more likely to have insidious effects that crop up later-so the 'bad petrol' could have been bought many tanks ago and the consequences just coming to light now!

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Wed 7 Dec 2011 12:33
Bad petrol - madf

Bio fuel goes mouldy with damp - condensation in a half empty tank will do the job nicely. Forms a gelatinous mess blocking pipe pick up points in the tank.. before the fuel filters.. As will cheap petrol without enough additives.

Edited by madf on 07/12/2011 at 12:34

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Wed 7 Dec 2011 18:13
Bad petrol - MikeTorque

I've had duff fills of BP Ultimate Diesel, felt the same as standard BP diesel, engine rattles more and less torque from the engine, I can tell the difference. Both lots came from the same garage, elsewhere I've not had any problems. My solution was to stop buying fuel from a company who can't guarantee the quality of their premium product deliveries. I use Shell Fuelsave diesel now, it's not as smooth a delivery for the car engine as V-power but at 8p per litre extra for V-power forget it.

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Wed 7 Dec 2011 18:36
Bad petrol - Bobbin Threadbare

Yey unthrottled is back!!! Teacher training is ok thank you. I am doing quite a large commute though.

I think my cruddy fuel might have been post-delivery time. The tanker was just leaving. I've never had it before and I did factor in the cold weather, as I have noticed that it makes a difference as well.

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Wed 7 Dec 2011 23:08
Bad petrol - unthrottled

Diesel (bio or dino) will grow mould if the diesel is allowed to come into contact with water.

I would say that the relative importance of the quality of petrol and diesel has reversed in the last 15 years. Petrol engines could be quite sensitive to fuel quality whereas diesel engines could run on old engine oil. Nowadays most petrol engines are not fussy, whereas diesel engines can be quite pernickity about their fuel. You'll nearly always benefit from extra cetane, but seldom require additional octane.

Petrol cannot grow mould. Neither can alcohol based fuels. Still waiting to see what these 'missing' additives are. I would shy away from premium fuels purely on the basis of the low turnover. I'd rather have fresh cheap swill than stale 'premium'!

Bobbin-nice to be back. Been too busy with work/family matters to get much HJ time sadly. Hoping to recitfy that. {chorus: groan}

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Wed 7 Dec 2011 23:42
Bad petrol - jamie745

unthrottled's been back for one day and im already bored knobless.

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Wed 7 Dec 2011 23:53
Bad petrol - unthrottled

Must have been something of sense in the post then.

Seriously though, the mystery of 'bad' fuel never seems to get resolved. I've had occasional problems of lumpy idling and hesitent acceleration that I was tempted to put down to bad fuel but could never convince myself that the problem wasd with the petrol. What do you run your monde..er..jag on? ;)

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Thu 8 Dec 2011 00:15
Bad petrol - jamie745

I havent had a Mondeo for years. You havent been away that long! Anyway, my Jag is a Lincoln underneath so nerrr! *thumb to nose etc...

Judging by your taste in cars i dont think problems are to do with the petrol ;)

I run the Jag on normal Unleaded from wherever is nearest at the time of requiring some. Its a simple system but effective.

Edited by jamie745 on 08/12/2011 at 00:19

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Thu 8 Dec 2011 16:26
Bad petrol - Roly93

Bio fuel goes mouldy with damp - condensation in a half empty tank will do the job nicely. Forms a gelatinous mess blocking pipe pick up points in the tank.. before the fuel filters.. As will cheap petrol without enough additives.

I,ve seen this gelatinous effect when I worked on the farm with an old combine harvester. Slime from the diesel totally blocked the gauze filter in the bottom of the actual fuel tank let alone the engine fuel filters. Though I cant see how alge can grow in petrol as I would have thought that petroil more or less has disinfectant properties.

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Thu 8 Dec 2011 16:29
Bad petrol - jamie745

In all seriousness i dont think ive had 'bad petrol.' I also dont particularly buy that theres a big difference between supermarket and 'branded' fuel. I get the same economy regardless of where i go really and i usually go to Sainsbury's or Texaco.

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Thu 8 Dec 2011 00:33
Bad petrol - Avant

Nice to have you back, Unthrottled - I'd been thinking you must have failed to live up to your name.... Jamie is no longer under suspicion. :)

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