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Hi everyone I am new to posting on this site and just wanted to warn about the use of E10 in petrol x350's!
After reading GOV advice about Jaguars and E10 I started using E10, within a few weeks my car started throwing up EML and restricted performance message. After switching off and on the EML would remain on. I used my Diag tool and the EML related to lean mixture bank2
P0174, When looking into what can cause this there a a multitude of things such as air leak MAF Oxygen sensor blocked injector fuel filter and the list went on and on! As my car a 4.2 se has 118 K and I could detect no air leaks or jittery rev counter I thought that an oxygen sensor or MAF could have an issue!
Before ordering anything I used some Wynn's injector cleaner and cleaned the MAF with a MAF cleaner spray...this did not work and every now and then when revving over 3k the problem would occur. I decided to run the tank down to 20 mile range and fill up with Esso E5 99 Octane.
The problem has gone away and the car has performed without EML or restricted performance message for the last 5 weeks and 2 tank fills/700 miles.
I for one will never put E10 in any of my Jaguars again and I would recommend if you are having same issues with your car that your first stop should be to change to E5 preferable Esso 99 octane before spending lots of money on this type of fault.

Yes, not at all surprised by your findings. I had this happen on holiday in Yorkshire last year when the "fuel crisis" caused panic buying and you were lucky if you could buy any E10 of any brand. You may not know but Esso 99 octane E5 is actually E0 or NO ETHANOL, except in the West Country or the North of England. Apparently it cant be marked as E0 on the pump as that is not a "recognised designation". Check the Esso website for your own confirmation.
I have run my X350 on it for the last year and also my old Triumph motorcycle and I can say that for the car the mpg has improved by around 10%. Also found E10 in the bike tank goes off after about 6 weeks and gums up the carburettors. So I say, why would want 10% ethanol E10 and poor performance to save a few pence per litre when you can have 100% petrol for a few pence more and no problems!

Hi commsinfo351,

Had exactly the same problem as you - changed to Esso 99 Supreme - Bingo, no more problems.

Yes, not at all surprised by your findings. I had this happen on holiday in Yorkshire last year when the "fuel crisis" caused panic buying and you were lucky if you could buy any E10 of any brand. You may not know but Esso 99 octane E5 is actually E0 or NO ETHANOL, except in the West Country or the North of England. Apparently it cant be marked as E0 on the pump as that is not a "recognised designation". Check the Esso website for your own confirmation.
I have run my X350 on it for the last year and also my old Triumph motorcycle and I can say that for the car the mpg has improved by around 10%. Also found E10 in the bike tank goes off after about 6 weeks and gums up the carburettors. So I say, why would want 10% ethanol E10 and poor performance to save a few pence per litre when you can have 100% petrol for a few pence more and no problems!

Thanks for reply I am also getting better MPG and I hope our posts stop people spending out for parts that are not required. Cheers

A similar situation with my old LPG X350. It was 1-2 mpg lower on LPG compared with the 95 ron petrol and less powerful, due to the lower octane rating of the fuel. Richard.

Richard,

It's not the octane rating of LPG that causes worse consumption in most petrol engines. LPG has a much higher octane rating than petrol, typically 112-114, but it has a lower energy value. In something other than a very high compression engine, it's going to have worse consumption.

E5 petrol with 98-99 octane rating will also have a higher energy value and typically improve consumption in most petrol engines.

Cheers

Paul

I meant energy rating. Butane, one of the constituents of LPG, actually has a lower octane rating of 94. Propane, another constituent, is higher at 112. Anyway, the word 'similar' in my post is relevant in context.

For the last 12 months, my local BP 24-hr fuel station has been selling E5 & Diesel Premium fuels at the same price as E10 & basic Diesel between the hours of 8pm & 5am. So no excuse at all for not using E5!

Maybe worth having a word with your local BP and see if they'll entertain the same idea!

Paul

I run my modified X358 XJR almost exclusively on Esso 99, as it is mapped to expoit the higher octane. It's a happy coincidence that in my area it is also ethanol free, the double bonus is that our local station sells it for less than Tesco ask for their cooking stuff. My wife's XFR runs perfectly happily on E10; E15 is acceptable according to Jaguar, but fuel consumption is measurably better (about 10%) with Esso 99, than with 95 octane. I can't really comment on performance as it's her car and I get earache if I thrash it.

Hi Phil,

I run my modified X358 XJR almost exclusively on Esso 99, as it is mapped to expoit the higher octane.

Interested to know more about the remapping on your XJR. Thinking of getting it done on my Daimler SV8 mainly to improve fuel consumption. When I looked into remapping the Jaguar SV8, I was told it wasn't worth it but it's the same engine/SC as yours. Did you have the 10% pulley done too, can't remember?

Flannels all round!

David Q