Hi Tyran

That is exactly my point, from my own experience the higher the octane the better my car runs.

She doesn't run well on low octane and to me it seems a crazy idea to have a great car with an engine that runs silky smooth and then not use the best available fuel.

 

Don't forget that not all pumps deliver the same quality of fuel, it's all down to the refining process that each producer uses; they will all do the minimum possible to comply with the minimum legislated standard.
If my car works perfectly well on 95 octane why would I spend another 4 or 5p a litre for 98?

 

Hi Mikey

"If the car is indeed not unleaded compatible, what do drivers in the UK do to get around the problem since leaded fuel has not been available for 10 years or so?"

Its not so much a problem with a 'daily driver saloon' as unlike the XJS many of these are not regarded in the same light as 'high performance' sports cars.

In other words they learn to live with it, whereas you wouldn't want to feed your thoroughbred race horse piles of junk food.

I suppose you could call leaded petrol 'a nickname' for 'old style fuel' that maybe didn't have as much ethanol in, as that what appears to be the cause of most of the problems with rust.

 

That would more than confusing to do so, not to mention very inaccurate. A true example of mixing apples and oranges.

The present panic over corrosion caused by ethanol is greatly unfounded as was the fears of damage to engine from unleaded fuels. Most of the concerns with ethanol come from the marine and garden tool industry, very different environment than automotive.

 

my only issues with the ethanol fuel is in things that sit. never had a issue with ethonol in anything that is used on a regular basis. my 30+ year old motorcycle burns ethanol fuel the same as non ethanol fuel till it sits over the winter. there used to be several stations that you could still get non ethanol fuel here but now its pretty much 10% ethanol everywhere you go. same issue with my boat after winter storage.

as far as premium vrs regular that has to do with the octane rating. witch is the fuels ability to avoid the fuel from self igniting. your xjs is a high compression engine that would require premium fuel. that's why it runs better with it.

a car that is designed to run regular will not gain anything by running premium.

however a car designed to run premium that is running regular will run poorly. and hopefully your knock sensor is working properly and retarding timing to reduce cyl temps and keep from putting a hole in a piston.

 

As I (somewhat vaguely) recall didn't the lead in petrol also help the valve seats in the good old days?
When manufacturers went to alloy heads didn't the valve seats start dropping out unless they had been replaced with something more suitable?
I remember having the cylinder head on my MGC refurbished many decades ago and having new valve seats fitted that could cope without leaded fuel.
I also remember valve bounce at 122 mph which was interesting.
What a great car, 2 seat convertible with an engine that weighed 635lbs!
Went like stink though, especilly with the fast road cam and lightened flywheel.

 

The key with vehicles with 'open' fuel systems like boats or engines that have carbs with tiny passages is to run them dry before storage.

Been doing that for 30+ years total, 20ish with E10, never had a problem.

 

Doesn't that depend on how long you intend letting the engine be 'dry'?
Especially carburettor powered ones?
Although to be fair I have only had experience (quite a while ago but certain bits still stick in my head [unlike anything to do with maths unfortunately]) but as I recall SU carburettors did suffer badly from piston seals drying out if not washed in petrol frequently.

 

Experiences apparently vary greatly.

In the last few weeks I've unburied two 2003 Corvettes that have been sitting for *years* with E10 in the tanks. They started up just fine and ran well. I didn't drive them hard but putt-putting about they drove fine. No CEL, no smoke, no nothin'. I have no doubt that the fuel is past its prime but I certainly didn't sense that anything was gummed up, varnished, whatever. Of course the fuel systems are very well sealed.

But, even with older design fuel systems I don't have any significant issues with E10 even after a 1-2 years of storage. Sometimes a little smelly but that's about it. If somethng more than a little gentle exercise is planned I pump out the old fuel and add fresh.

After two years...well...sometimes there's a problem...hard starting, lots of smoke, etc.

When I hear others report that the E10 'turns to goo in 30 days' or similar I really have to wonder why I'm not having the same problem, as I deal with stored cars all day long. The cars are stored inside and dry so that probbaly enters in.

I don't think age alone is a particular issue.

Cheers
DD

 

Ok, but could you be a little more specific?
Not entirely sure what CEL is (as in I don't know).
Regarding the ethanol situation I can absolutely guarantee that over here 99.9% of the driving population haven't got the foggiest idea of what you are talking about. Nobody knows (apart from me obviously).
But, a couple of points:

'But, even with older design fuel systems I don't have any significant issues with E10 even after a 1-2 years of storage. Sometimes a little smelly but that's about it. If somethng more than a little gentle exercise is planned I pump out the old fuel and add fresh.

After two years...well...sometimes there's a problem...hard starting, lots of smoke, etc.'

Everybody knows that you can't run a Gimp on ethanol.
if your Gimp is starting to exhibit starting and smoking problems then it is obviously time to part it out; you can gently exercise it as much as you want but, deep down, you know what you have to do.
Buy another Jag

 

Check engine light




What's a "gimp"? A worn out engine?



Are you joking or what?

I'm talking about smoke from stale fuel.

Cheers
DD

 

Here in the colonies we usually store summer toys from Nov. through April. The winter toys get stored from Apr. through Nov.

The entire fleet runs on E10 as that's the only game in town but given that small engines and marine stuff have ALWAYS had problems during storage, the procedure would be the same irrespective if I was using pure gas or E10

The toys with open fuel systems get their carbs run dry. The boat goes one step further and has it's fuel tank drained dry. It's amazing how much non-fuel related crud accumulates just through refueling.

The toys with closed fuel systems get carefully positioned in their parking spots and the ignition is shut off and battery tender attached. That's it.

For reference, and in connection to the sky-is-falling stories about E10 causing massive corrosion, here's a peek inside the fuel tank of my old Corvette. It's had a steady diet of E10 for about 20 years:



Does anyone see any corrosion or accumulation of water?

 

10 years?
Personally, unless it was a barn find Cobra, Ferrair Daytona or similar then I really wouldn't waste my time.
Jags are rubbish unless they are driven regularly; assuming that you can get the engine running you are still hundreds of hours and thousands of (insert local currency here) away from having a legal, useable car.
Everything will need replacing; all fluids, filters, hoses, brake lines, fuel lines, the brakes will be seized, the tyres goosed but if you are really lucky then vermin won't have got into the wiring. And the upholstery.
Not to mention rust because our Jags do have a fondness for the brown lacework.
Scrap it, sell the bits that still work and buy another one; there are plenty out there and it will save you a load of grief in the end.
Of course, that it just my opinion.

This idea is what's rubbish (respectfully): after 12 years in storage, and after an oil change and a new battery, mine started right up and is running perfectly. After another oil change, coolant flush, brake system flush and tune-up, it passed a safety inspection and smog inspection in CA and has been performing flawlessly for nine months. Your statement is a foolish over-generalization; each car should be assessed individually.

 

Have to agree with you on that! after a 10 year layup, the engine turned over about 4 times then started and ran like a bird, as if I had been using her everyday.

Also passed the MOT first time without any problems, except that on the following day, the near side (uk) front Caliper stuck, which got so Hot that the Car very nearly went up in a 'Fireball!'

But if you can gloss over that minor teething problem! once I had renewed them and almost everything else to do with the brakes: Hoses/Brake Pads/Calipers etc. She ran as good as new!

Apart from a Mystery squealing under the bonnet/trunk (loose fan belt)

And a Terrifying squealing! going round corners even at 10mph
(Brake shims supplied with the pads)

Thanks to 'Greg' for sorting that out.

 

Hi . can someone explain where the fuel pump , fuel filter , and fuel relay are located please on my 1992 xjs 4.0l as its just not pumping fuel through :

 

Hi

This diagram might help

https://www.google.co.uk/search?q=fu...ml%3B584%3B415

 

Scrap the car...?

Harsh... Very harsh... !!

Toss it my way... I had the '88 Convertible and loved it dearly...!!
While I do love the electrical improvements in the '95 I still think the old body XJS was a more beautiful car!!

Pretty good advice on the piston ring concerns... I have salvaged an engine ('70 Cuda) that was seriously gouged by a broken piston ring: bored out larger... in retrospect I SHOULD have sleeved the single cylinder... but on your car all the cylinders ARE SLEEVES.

Incredibly expensive ones!!

As for your concern about cross threading SPARK PLUGS... BE AFRAID (it is good thinking).

Use a short piece of neoprene fuel line slipped over the insulator (top) to get the plug started in the threads... and most of the way seated.

Easy and cheap way to FEEL the plug going in...

If it is not threading easily you are not properly aligned.

If you feel it needs pressure to get it done... immediately stop and hire a good mechanic.

Very important to dress your plug threads with anti-seize compound (all owners of aluminum component engines [like carburetors... especially] should keep some anti-seize ON HAND.

 

Don't forget to put some anti-seize on those spark plug threads, especially important with aluminum heads.