I just bought a 1989 XJS V-12. I have not put any fuel in it yet. I saw somewhere it is supposed to use premium high octane pump fuel only. Is this true? I don't want to put the wrong fuel in it. Thanks.

 

I'd be surprised if Jaguar suggested anything but premium unleaded. That's all I run in both of my jags

 

It was designed for 91 (US/Canada rating) or 95 (European rating), which is the same fuel. It's premium in North America, regular in Europe. Premium in Europe is 98.

 

91 it is. THANKS !!!

 

Should use the highest octane available, make sure your fuel map is selected for it I just noticed my car's map selector plug disappeared...was running in 'low power' mode for god knows how long. Your car is an 89' so it should have this option. Sometimes I even toss in a 1-gallon of xylene paint thinner for MORE octane on highway road trips. Lots of goodies you can buy to if you want to squeeze every bit of mpg out, I'm a huge fan of Archoil products, lots of gains there.

 

Careful not to use E85 though even though it has 100 octane. You need to greatly enrich the system and advance the timing to take complete advantage of the potential it has to add about 10% more power.

 

Careful not to use E85 though even though it has 100 octane. You need to greatly enrich the system and advance the timing to take complete advantage of the potential it has to add about 10% more power.

 

"fuel map"? That's new to me. I don't have an owner's manual. I'd appreciate any info. THANKS !!! (I'm new to the Jag world).

 

[QUOTE

 

Yes stay away from ethanol fuels! Up in Canada 94octane is ethanol free the rest are contaminated.

fuel timing plug:

https://www.jaguarforums.com/forum/x...lector-228280/

Its just a wire loop that plugs into the end, and selects advanced timing.

 

Probably best described as a 'timing map' rather than fuel map, as it alter timing, not fueling, as I recall

But, you might not have it at all. It was a feature on the cars with Marelli ignition....which was introduced part way thru the 1989 model year (USA model yer, that is). If you have the earlier Lucas ignition you won't have the 'mapping' choice.

As for ethanol, which has been mentioned, well, that can be a touchy subject. I've been running my old Jags on E10 for decades with no problem. FWIW

Cheers
DD

 

Didn't the States get the Marelli for the MY 90? My mid 89 UK model has the Marelli...

Regarding ethanol... There was a hate hype here, as all our fuels have at least 5% ethanol now. I always fill in e10 as I have no worry driving it. People would be driving cars, running it on E10 and claiming that the E10 destroyed the engine. It would - not kidding - cause cambelts to snap, ignition coils to die, clutches burn out... You know, impossible things. I'd have no worry driving my V12 on E10 or more...

 

It was during the USA 1989 model year, maybe half way through, at VIN 156xxx or something like that.

Experiences, and anecdotes, very greatly on the subject. I won't say the complaints are entirely unfounded but I think E10 has become a too-favorite whipping post. I tease some pals by saying "If you're girlfriend got pregnant you'd blame E10 gasoline" .

FWIW, my 1988 Jag owners manual explicitly says E10 is OK.

Cheers
DD