Do cars 'get used' to a certain fuel?

[thismonkeyhere]

Supermarket fuel gets slagged off a lot on here, but I very rarely fill up anywhere other than Sainsbury's, with no obvious issues, except:

Recently filled both my cars (both diseasel), through necessity, at a local 'big brand' filling station, and they both seemed to underperform - rougher, slightly sluggish. Not enough to be a real problem, but noticeable.

Next fill, back to Sains - both noticeably smoother and more responsive now.

So - does the ECU and what have you, learn and adapt to different fuels, and st or not, they just prefer supermarket fuel? Is there that much difference anyway? Am I just imagining the whole thing? Cuckoo...

[kambites]

Some petrol ECUs can adapt their ignition timing to different octane ratings but I think they do it pretty damned quickly. I don't know about diesels.

[trashbat]

kambites said:

Some petrol ECUs can adapt their ignition timing to different octane ratings but I think they do it pretty damned quickly. I don't know about diesels.

I've heard several times that it takes 3-5 tankfuls to fully transition from say 95 to 99 RON.

[TooMany2cvs]

Very definitely it's an issue.

If you take a car that's used to being run on diesel, and fill it with petrol, it will sulk. But if you'd run it from petrol every tankful from new, it'd be fine on petrol. Run the car which is used to petrol on diesel, though, and - again - sulk

[vanordinaire]

TooMany2cvs said:

Very definitely it's an issue.

If you take a car that's used to being run on diesel, and fill it with petrol, it will sulk. But if you'd run it from petrol every tankful from new, it'd be fine on petrol. Run the car which is used to petrol on diesel, though, and - again - sulk

Damn, beat me to it.

[r11co]

There were excepts from a report published on one of the Jaguar forums from an engineer who did consultation work for VOSA who had investigated this very phenomenon and come to the conclusion that cars do indeed get 'addicted' to certain additives in fuels to the extent that when a fuel without that additive is used the car will not run as well. It was a scientific study, and the conclusion of the report was that the findings tied in with the perceived benefits of 'premium branded' fuels as being better than non-premium fuels when in fact there was no performance gain in using them, but a noticeable (albeit temporary) drop in performance when switching away from them.

Kind of also ties in with the anecdotal evidence on here from the 'my car runs crap if I don't use super-duper Brand X' brigade!

Far be it for the petrol companies to come up with something like this (given the millions they spend on chemical research and development....)