98 octane in Citigo

Summing up:

There are markets where fuel is often less than 91RON...

There are places where fuel is supposed to be 91/95 etc but isn't, maybe even the UK....

Ups/Citigos etc sold in S. America, S. Asia etc may well have a map that is set or scaled for lower fuel ratings...

The difference between the 60PS engine and 75PS engine in Europe is just the map. The higher power unit has a map that allows more fuelling and more timing advance - everything else is the same as far as I know. My point was that ignition timing is alterable via the ECU. If you have a 60PS, it should be fairly easy to turn it into a 75PS for reasonbale money!

Knock-sensors will retard timing, but only up to a point, depending on the ECU's map. The 'map' is a set of linked look-up tables forming a multidimensional matrix, but sometimes look-up values are 'off the map' and defaults are used. It's a basic programming thing. I used to handle similar stuff when I wrote serious code back in the day....

With a vehicle not owned from new, you have no idea of its provenance, which may include poor attempts to change the map....

And to the original point....

If a pinking problem occurs (and we have no real data on whether the OP had actual pinking as perceived, or if it was something else) it could be problems with fuelling, air leaks, or ignition timing.

If a problem has occurred recently and suddenly, the first question should always be "what has changed?" (i.e. a service maybe done badly, a different fuel station, general fiddling under the bonnet ).

I'd check for any sensor errors using an OBD dongle first.

But my first bet is on an air leak, if it really is pinking, putting bad fuel aside for now. Meaning that the engine is sucking in a bit more air than has been measured by the MAP (i.e the thing like a MAF, not the map in the ECU) so it runs lean, possibly beyond the point where knock sensors are able to retard ignition via the ECU. Possibly loose injector or spark plug, leak in inlet manifold, dirty MAP etc.  If not that, then it may be insufficient fuelling compared with air coming in. Possibly dirty injector(s), weak fuel pump (unlikely as this throws a definite error code on OBD). Some injectors (usually DI - I don't know about MPi injectors like on these cars) are often coded to to the ECU, owing to slight tolerance differences. If you change them, you have to recode them on many vehicles, to match their specific flow characteristics (stamped on the injectors), but that is high pressure stuff.  And you also need a decent spark, so plugs/coils should be checked.

The alternative is to spend a while looking for the non-existent distributor, and clean the cap. And clean and reset the the points, and check the little vacuum-driven weight is working to advance/retard the ignition. Just kidding.

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Edited 28 July, 20205 yr by freemansteve