Never resolved, primarily due to my lack of interest in fixing it. The car rarely gets driven these days and I just put up with the fuel gauge quirk in the same manner as I 'drive around' the transmission lurch and RPM surging when cold.

My bad.

The fault has not really changed since my last update in 2013. Full gauge indication means a full tank. 3/4 indication means I have a half tank and 1/2 indication means I'm at about a quarter tank. I also refill every 450-500 KM irrespective of what the gauge reads.

I'd be tempted to just put a full jerry can in the tank and drive around till the engine dies to see what gauge reading I'd get, but that's not good for the fuel pump.

 

Have you tried using premium fuel?
I've heard it works wonders due to the superior additives.

 

Thanks, Bob. I'm aware this is an old thread, but I do appreciate your humor. .

I've already been through the TSBs, AllData, the Workshop Manual, rocking the car in Engineering Test Mode (ETM), and most of the fuel gauge threads on the UK Jag Forum and this Forum, which of course led me to this particular thread. Mikey's car and problem are similar to mine, which I'm happy to say that I've fixed. I really just wanted to compare notes with his fix, if he had one. I'm not looking for solutions.

Before my fix, I tracked the operation of my malfunctioning fuel system extensively via a spreadsheet using the Engineering Test Mode data. My malfunction began about 5 months after installing brand new pump and sender units so I suspected the malfunction was related to either or both of the units themselves, or how they were installed.

Turns out my problem appears to have been caused by the sender float getting hung up on the 2 transfer hoses that run from the bottom of the sender unit across the tank to the fuel pump. So the sender float was not dropping as that side (left side) of the fuel tank emptied. This caused my fuel gauge to always read near full, even as I ran it dry.

BTW - approximately 5 miles before I ran out of fuel, the MIL displayed "Fuel Computer Data Error".

Immediately after running out of fuel, I took ETM readings:

Range = 169
Raw Fuel1 = 28
Raw Fuel2 = 153
Fuel Filter1 = 0
Fuel Filter2 = 213
Fuel Percent = 255
FuelDriver = 0

It turns out that relying on the trip computer's RANGE reading to estimate how many miles until empty is a REALLY BAD IDEA. This is because range is apparently calculated using the position of the floats in the tank. If your floats aren't working correctly, range will be wrong. I ran out of gas even though my trip computer calculated my RANGE to be 169 miles.

So when the fuel gauge is not reporting correctly, it seems the safest way to estimate the amount of miles until empty is to reset the trip computer at fill-up so mileage reads 0, then monitor that mileage reading on the trip computer. If you know how many miles you typically get from a full tank of gas (multiply 18g X's mpg), then fill your tank when the trip computer miles approaches that number. This only works when you fill the tank.

Apparently the trip computer does not rely on fuel tank data to calculate miles traveled, so this should be a reliable way to not run out of fuel.

And rocking the car will show the float/sending units are working correctly if you have a near full tank of fuel and your floats are working correctly. My floats worked correctly with a full or near full tank of gas. So rocking the car caused the ETM RawFuel 1&2 readings to fluctuate, as they should. TSB says the senders are working correctly.

BUT with less fuel in my tank, rocking the car caused NO movement in the RawFuel2 reading, which was helpful for targeting where my problem was, but only when the tank was closer to empty. The TSB is silent on this situation far as I can tell.

Also, I took many photos and intend to write up my fuel system adventure as I think it will be helpful to others here. I'll start a new thread when I do. I'm no expert and I'm sure not a mechanic. But doing some detective work, not being afraid to shove my hand in a tank full of gasoline, and understanding the basics of how the entire system works saved me lots of $$.

Like I said, I'm no expert, especially compared to many of you guys on this forum whose experience I really admire and whose opinions I really respect. Just hoping I can help in some way.

 

Yep, did this. See my post #23. Worked with a full tank; didn't work with low tank. Helped me identify where my problem was and what my problem was.
Thanks,
Steve

 

Ahhh- between that and using non-synthetic oil it's amazing that the car hasn't done even worse things. Maybe initiating global warming?

 

Thanks, Mikey. I'm no mechanic but I can tell you with little more than a hammer and the end of an old hockey stick, I pulled out the pump and sender units, changed the float/sender assemblies on each (Jaguar has updated them and sells them separately), and reinstalled the entire mess in my driveway. Didn't even have to fully remove the rear seat.

It appeared as though my left float was hung up on the transfer hoses, which may have been causing the gauge errors. Changing out the float/sender assemblies was just additional insurance, as there was a TSB about it. It was the only part of the job that actually cost me any $$.

I don't know if your problem is same as mine but I can tell you it was worth the effort for me to figure it out and fix it, and it really isn't hard.

Of course mine is my DD so I'm neurotic about having my fuel gauge read correctly. I've got pics & info I'm gonna post soon but if I can help you please let me know. Steve

 

I really appreciate the offer and will take you up on it when/if the time comes to take action. Other things in life seem to keep getting in the way.

 

Rick -
This is from the Jag dealership in Columbia, South Carolina from which I source all my Jag branded parts. It's for 2005 S-Type 3.0L; these are the current superseded numbers:


FUEL SYSTEM COMPONENTS / Fuel pump
Part Number: XR848122 fuel pump 2005-08, w/o supercharger


FUEL SYSTEM COMPONENTS / Fuel sender unit
Part Number: XR848117 fuel sender unit 2005-08, w/o supercharger


PM me if you need their web address for pricing, as they're not a Forum sponsor. Steve

 

steve,

I don't know if you have come across my "talking gas tank" adventures here. As soon as Joyces Jag rolled unto our driveway many years ago, I could hear the gas tank saying "i am empty some seconds after Joyce walked into the door from work. There have been several times throughout our ownership that though the "fuel data computer blah blah" was lit. I had never ran the vehicle out of petro going to fill er' up, close I am sure but never.

Back to to thread. Joyces Jag's fuel gauge has been acting up a month or 10, can't really remember anymore. Same kind of symptoms. Gauge works correctly until about 3/4 full, hangs there for a while (days). I remind the S.O. "better get gas" every few days, she complies and usually gets in about 12 gallons or so, gauge returns to full.

The other day my DD was down and I was waiting for parts. I truly have not driven JJ in quite awhile. I would drop Joyce at work then proceed to drive her Jag like a man should, you "blow out the carbon". I ended up fixing some of the small jobs that needed attention that I have blown off the next few days. I did some spirited driving to say the least.

Although I did not park shake and bounce, I did shake, roll and took some aggressive turns. Something kind of corrected the fuel gauge to the point where the needle would go from full to 1/4 tank then get stuck until next fill up.

I have been using Columbia JLR for a couple of years now. If I cannot find their parts on ebay, which they sell discounted (free plug fellas'), I call and is it Dan(?) will put the said part on ebay for me, I buy now, and drive down to pick up. Less than an hour ride for me, I usually will pull the kids out of school, take them, grab parts then hit the Riverbanks Zoo for a quick walk through where we have been members for years. The zoo is a few minutes away for them. Thank you for the heads up on them.

Please do, post up your DIY fuel sender adventures w/pics! I am sure many will benefit especially me . I will be ordering the new sender units and wait for your comprehensive DIY. Thanks for posting updated part numbers! Be sure to add old #'s with superseded new #'s in DIY.

Damn, just went to ebay XR848117 fuel sender $416. and change... XR848122 fuel pump $487.and change, not from our buddy in Columbia. I guess I may be reaching down into a tank of gas, maybe full, maybe somewhere in the middle or possibly quite dry in the next couple days to see if somehow one of the floats are getting stuck.

 

Yes, I definitely stepped into the wayback machine and read your earlier posts on the topic, Rick. I know at one point you were taking readings etc. I took it one step further and created a comprehensive spreadsheet of my ETM fuel numbers, which was extremely helpful, esp before & after I ran out of fuel (thank god for wives/SOs, right?).


I will be posting my entire fuel saga as soon as I can, Rick. I hope it will be helpful.


Rick -
Our friends at ColumbiaJLR - Jim Whitesell and Cliff - have these parts for the '05 S-Type 3.0:
Sender: XR848117 = $340.23
Pump: XR848122 = $395.85

I purchase through their excellent website which has latest Jag part numbers and lowest prices of Jag branded parts I can find online...
http://oemdiscountcarparts.com

BUT - Because your fuel pump is working, it's likely there's no need to replace it, so don't spend your $$ yet! Your wonky fuel gauge suggests that maybe only the sender parts of the fuel system have failed, or possibly are just hung up - if the "sender tile", which has the float attached to it, has failed, it's cheap and easy to replace.

Jaguar sells the replacement sender tile assembly with attached float for the fuel pump (XR854118), and similar one for the jet pump (XR854119) at about $60 each,




and the harness Lead-link (C2S40438) for about $50 each - your car has 2 of these (top wire set replaces bottom wire set)...



Throw in 2 new gaskets and you can rebuild the fuel pump sender and jet pump sender for a fraction of the cost of replacing these units. This procedure is described in TSB S310-07; AllData also covers the procedure in greater detail.


SOME ADVICE: When my fuel gauge was mis-reporting fuel levels, I started EVERY trip by reading and recording the fuel ETM numbers. I highly recommend that anyone else having gauge issues do the same.

I found the important number to watch was FILTER FUEL 1. This number appears to represent the fuel level in the right side of the fuel tank where the fuel pump is located. Logically, this is the area of the tank from which fuel will be drained last, and will be filled first.

About 5 miles before I ran out of gas, FILTER FUEL 1 = 10. After running out of gas, FILTER FUEL 1 = 0. After I put 2 gallons of gas in my empty tank, FUEL FILTER 1 = 38. After I filled the tank FILTER FUEL 1 = 253.

When I ran out of fuel, FILTER FUEL 2 was 213, Range was 169 and my gauge showed I had over 1/2 tank of fuel. This was clearly an error, as I'd just run out of fuel and FUEL FILTER 1 = 0. So my problem had to be in the left side of my tank where the ETM numbers (FILTER FUEL 2) were way off, right?

So the takeaway is:
1) Until you repair your fuel sender problem, DO NOT LET FILTER FUEL 1 hit 0;
2) When FILTER FUEL 1 gets to 38 you have about 2 gallons of fuel left;
3) If the numbers from either side of your fuel tank don't seem to jive with your fill-up numbers, that is probably the side having sender errors; and,
4) Don't overlook the possibility that the gauge itself is faulty.