Currently on my next disaster - fuel tank - I just cleaned half a litre of black tar out of the swirl pot, the filter in it was just a black blob of nastiness, the inside of the tank is a disgusting black mess, the over subframe rubber hoses are totally pooched (was replacing those anyhow).

Suspect I'll be replacing the fuel tank if I can find one - just looking for cleaning options. There's no way I am prepared to expose 12 new injectors or a new fuel pump to this crud.

Anyone know any solutions that will do a half decent job without removing the tank - industrial grade Caustic Soda ?

Convinces me that most of these will it run youtube things are faked - no way my car was hitting the road again or even running right - all thanks to the modern 'cracked' fuels and bio products aka methanol. Darn thing has only been sat 3 years, though I think it had stood for a while before I got it - but it ran fine - maybe it will be better than fine when I'm done.

Incidentally how is the filter basket held onto the swirl pot pickup - mine fell off - no sign of any kind of retainer.

 

Ben
Removing the tank is pretty easy on a pre-facelift coupé. I STRONGLY recommend you do this because the bottom of the tank WILL be iffy. Also with the sender removed you can easily see the condition of the inside of the tank, which, believe it or not, will probably be OK unless the outside is porously rusty.
The take it to your local radiator man and get him to coat the entire bottom of the tank with radiator solder. Job done; see pic of mine done 15 years ago and still fine:

Half painted radiator solder covered fuel tank bottom.

Then throw out the rubbish pad beneath the tank and repace it with 1/4 inch of neoprene rubber. Change all the small hoses that go to the evap cannister and change any others that are iffy. New OEM ones are about.

The sock filter is just a push fit onto the spigot, but a better idea is to insert a Wix 1/2 inch filter into the feed from the main tank to the sump tank, ditch the sump tank sock filter, ditch the huge OEM filter behind the spare wheel and sort out a nice Zytec filter as in this photo, while relocating the pump as also shown. This also eliminates about two yards of flexible piping!:





The bottom cover goes over it all no bother.

SNG have new tanks but pricey.
It may cheer you to know that on a mate's car that was running perfectly I emptied four pints of what looked like Guinness from the sump tank, but the main tank was fine.

 

I have had a boroscope in the tank and it is depressingly bad, I should have it out tomorrow, it is all undone with the exception of the breather hoses that are being a bit of a tart, going to let it soak a few days full of caustic soda and if that doesn't do much I will replace.



I'll wager those blisters in this black muck are most likely rust - ignore the timestamp I haven't bothered setting it.

 

On small gas tanks we used to use BB's from BB guns and water to shake around the inside of the tank. Knock anything off and rinse a few times then dry properly. I will admit I don't know the physical size of the XJS tanks.

 

Too big for my arthritic *** to be swinging around with anything in it ... it is 80% the width of the car and about 18" 'square'

Would be easy if there was a decent inspection port / access, I will do what I can but I've gone too far on this car to continue with anything that is too compromised.

 

Modern fuels don't sit well, at all. I've run cars on 20 year old fuel, 20 plus years ago before they got wonky. Now after a year it's often iffy. Can't let cars sit, now more than ever.
I don't think it's *just* ethanol blends either but they are certainly worse.

 

It isn't just Ethanol but the production method. When I started motoring in the days of leaded all petrols were distilates, they 'improved' profits by extracting more from the same base stocks using a process called cracking - but that leads to a more unstable product - not an issue if it is used but fuels today have a sell by date (or should have). The use of fuel stabiliser is mandatory I think but so is at least running regularly, this experience will change how I deal with all my classics - I drove the XJS to where it currently sits and it has been there only 3 years.

 

To many young people that grew up knowing nothing but crappy fuel "low mileage" is starting to be a dirty phrase.
Rubber needs to be exercised too, I don't think any of it is what it once was either but it's not as big a thing as the
fuel issue, yet anyway.

 

My fuel tank is toast - when I got it out there was enough fuel left in it to identify a wet patch in one corner on the bottom - the tin worm wins - won't even be trying to clean this tank.

 

Running regularly is a good idea for the fuel pump, injectors, etc. but it doesn't solve the issue of fuel in the tank.

I guess a fellow could drain the tank every 12-18 months or so, replacing the old gas with new.

Or, once drained, leave the tank empty and add a couple gallons when needed to run the car.

Anyhow, I agree that's there's more to the story than just with/without E10. I've often wondered about the different "additive packages" in gasoline and how well they age. Not to mention ambient conditions (dry versus damp) in the storage area.

Cheers
DD

 

I grew up with cheap 23 cents a gallon gas. So trust me when I tell you old gas is bad. It would go bad in within a year ( and back then we didn’t have stabilizers). Well, you could buy a bottle of METHANOL ( alcohol made from coal or wood waste) and maybe get the light ends back enough to burn that tank of gas. But METHANOL is positively lethal. Unlike ETHANOL. If you’ve ever drank a beer, wine, or any alcoholic drink, that’s what you are drinking, ETHANOL.
Cracking is the process used to convert crude oil to the various products like GAS / DIESEL / Jet fuel etc.
What is different now is they are extracting more from a given quantity of crude. ( not just the added ethanol).
But that all depends on the grade of crude oil. For example here in the states we are getting mostly a lot of light sweet crude* While much of today’s crude is heavy sour. ( pretty much doesn’t matter where it’s from by now), it’s just older wells tend to produce more heavy sour.
* from the fracking process used to extract oil from shale.
Please don’t confuse ETHANOL with the bad effects of METHANOL.
Ethanol doesn’t attack the rubber in fuel lines because it hasn’t been legal to use Rubber for fuel since the late 1930’s instead it’s synthetic like butyl.
Jaguar, though had a lot of trouble finding good high pressure hose for their EFI. It took 3 recalls to eventually find a good hose. ( read SAVING JAGUAR) thank you PORSCHE.
METHANOL will attack anything, if you drink it you die. Aluminum, copper, brass. Even steel! Stainless steel is required if you’re going to use METHANOL. Plus only certain gasket material will hold up to METHANOL plus breathe it and you can get cancer. Your skin will absorb it and cause cancer on internal organs.

ETHANOL doesn’t do any of that.
it will evaporate quickly. light ends, (needed for starting) go first. It will also absorb moisture ( gas tanks are vented to air). But there already is water in gasoline.
Ethanol is high octane. About 105. Plus it has extra free oxygen in it so there is as much as a 10% power increase. In addition, Jaguars because they are batch fired tend to build up deposits on the back side of intake valves. ETHANOL removes those deposits.
One final benefit of ethanol. It burns cooler than gasoline. ( not enough to offset a faulty cooling system) but it helps us racer’s and anyone really working their engine.

 

well explained.
It’s more complex than the additive package. Oil refineries are typically set up to use one sort of crude. Older refinery’s mostly use heavy sour crude, because the light sweet crude AMERICA is getting from the shale fields isn’t suitable. So we are selling our light sweet crude. And buying enough heavy sour to blend it. So the refineries can continue cracking it using the existing process.
Estimates as high as a Trillion dollars yup, TRILLION! Is what it would take to convert.all the AMERICAN refineries to use our own light sweet. For obvious reasons that is not likely to happen.

 

Given the fuel mileage most of these cars get it wouldn't be difficult at all to drain a tank every couple months.

 

The eth blends we get here in the US tend to be not so great in older cars. Especially carburetted.
Even the EFI ones get slightly worse fuel economy and presumably power, and the stuff really does
not sit even as well as straight modern gas. CIS, LH, Motronic etc of that era
all seem to deal with it alright-enough if everything is in order. Carbs not so much. Least in my experience
back east. The last carb I had to deal with on a car was a 70's Solex and I thought I was losing my mind
till someone pointed out that even though the pump didn't specify there was likely low % eth fuel there.
Sure enough some straight gas and most of the oddities went away. I'd never paid any attention to it
prior to that. Given a choice I don't run it in anything older than the mid 90's. Even the 5.3 LS in the stable
here lost almost 2mpg going to e10.


E85 is pretty interesting and been used to good effect, especially with the performance crowd but it's
still a little iffy. I had a panther chassis ford that was a flex fuel rated and it has some specific
service requirements when running E85 often, increased oil change frequency and such,
and the mpg was down even with the factory designed system. But with enough boost
and the right tune one can work wonders apparently. Most engine management systems
support a fuel eth content sensor now so if you get a little weak or a little strong batch it can adjust
the tune as needed. Pretty cool stuff.

 

a good tune on the ECU. Won’t hurt your fuel mileage that much using E85. My FORD F150 has flex fuel and using 10% ethanol I get 22.4 mpg on average. ( over the last 108,000 miles.).
When I switch to E85 ( which I do a lot since it’s as much as $1 a gallon cheaper) drop to around 20.7 mpg. Adjusting for lower fuel mileage I still save about $20. A tankful.
That’s on a 5 liter V8 4x4 pickup.
Cold weather affects every fuel about 2 mpg or worse (30-40 below f )
As for service the owners manual says 10,000 miles between oil change. The dealers says 5,000 and that’s about what I do using semi synthetic
I stretch it out to 7,000 on pure synthetic.
My Vintage racing V12 Jag sees nothing but E85. (That’s about 105 octane) $2.39/9 a gallon compered $4.19/9 for 93 octane and $12- 15 for the racing gas. ( with lower octane.).

FAIR NOTICE; the fuel mileage numbers require normal driving which is really hard to do using E85. The added power brings out the little boy in me and I love to smoke the tires going on the freeway on ramp!! ( you’d think at 76, I’d grow up ) ;-)

 

What year is your truck? I would assume the newer the better for such.

As of about 2007 or so in a panther chassis Ford said if you use E85 more than 50% of the time, go to a 3K oil change interval.
And run a tank of regular gasoline through it every few months. It's in the owner's manual. I read an OCI and discussion
at some point about what it did to the oil but there was a reason for it.