Hi guys;

My XJS gauge does not seem to move. Or rather it moves very slowly. Extremely slowly..... I have driven about 34 miles today around town and it barely moved from 3/4 to 1/2. It’s actually still not at 1/2.......Not sure if I have become accustomed to my X type daily driver drinking gas like cheap wine, but I have not driven my XJS in a while so this could be normal, but I recall the XJS drinking more than this.

I did replaced both the anti slosh module and the sender in 2017.

The gauge does fluctuate around when I make turns, as fuel moves around, so I know it’s working, just can’t seem to get it to go down at a normal rate.

Perhaps the aftermarket sender is no good?

Any ideas?

 

When I replaced mine the first time, I didn't change the gasket and I couldn't get it to work.

About a month ago, I decided to change the gasket to a genuine one.

The gauge now works quite well...

Who would have known!

 

i had a fuel gage problem seemed to register some times but not accurate!
changed the tank sender , and it was worse??

took sender out and BEHOLD the silly me had overtightened the sender swing arm ,it would stick and the loosen, never consistent!
perfect now!

 

I have a fuel gauge that's doing the whole "off by 1/4 tank" thing. When full, it shows 3/4 full. When it shows empty, I still have 1/4 tank left.

I've swapped out the fuel level sender in the fuel tank with a new one.

I switched out the relay looking sensor in the trunk that controls the sensor without any change. That one was a used one, and I have no idea if it was good or not. I don't even recall how I acquired it.

 

spikegaga,

I know that you said you replaced the anti-slosh module but it still be causing the problem. Many of the "new" A-S modules were built 20 years ago and can suffer from the same problems as used ones. The capacitors can "leak".

The A-S module works by taking the output voltage from the sensor in the tank and then "smoothing" it to avoid fluctuations that occur when the petrol in the tank moves about.

A typical symptom is an under-reading gauge. As you've also mentioned that the gauge fluctuates when you go round corners, it implies that the A-S module isn't working properly anyway, as it should stop those fluctuations.

You could see if the gauge functions more accurately without the module in the circuit, which may help to determine if the module is at fault.

You can bypass the module by disconnecting it. Then use a short piece of wire to bridge the input and output voltage pin sockets in the module holder. This sends the voltage from the tank sensor direct to the gauge. You may get minor fluctuations when the fuel moves about and also the low level warning light will not illuminate. But the gauge should read accurately.

The 2 relevant sockets are the 2 in the "middle" line of the holder sockets. It's the adjacent horizontal and vertical ones (if that makes sense).

Good luck

Paul

 

my fuel gage reads high when on charging in shop ,then goes down when driving?
ron

 

Thank you. I did not think to connect the fact that the fuel level seems to be fluctuating a every turn I make, this showing that in fact the AS module is not functioning properly.

I am going to order another one directly from the UK or look into fixing it. I am hoping the ones Jaguar is selling on their website are not old parts

 

Well, I checked the DAC7624 Slosh module and it has a production date of 2006 on it. I am replacing it before I try replacing the sender itself. (Both are recent, but as I mentioned above, the sender is aftermarket)

part of my problem may be that the slosh module seems to have popped out of its place and was flopping around in its area upside down. When the new one gets in I will be careful to tie it down.

 

spikepaga,

Before you replace that module, just remove it and bridge the appropriate terminals. If the problem doesn't go away, then I wouldn't buy a new module, but start looking at sender or gauge problems.

Good luck

Paul

 

Thanks. I will get to that this week, although, today I drove the car and got the gauge under 1/2. This was after fooling with the AS module as I mentioned above. My guess at this point is that it’s the AS module about to go out, or the gauge is moving extremely slow because I have been driving a daily 4 wheel X type and my V12 E for the past 8 months exclusively and I am used to seeing gas levels drop almost as I accelerate the car

 

So I bridged the appropriate terminals and level shows the same . Also, I did manage to get the tank fuel level under 1/4th , something I never do, specially with old cars where fuel pumps can get stressed out, but I wanted to make sure the sender was working without having to take it out, which is simple but not fun to have a fuel odors on my freshly cleaned trunk.

I do ,how ever, notice that on some sharp turns the needle moves around significantly , and at other times it remains in place. Mostly stays in place after I hooked on into it’s appropriate bracket. I believe the current AS module is on its way out.

I will I’ll be receiving a new AS module from Jaguar in the U.K. on Monday. I hope this part is more recently made than my last 2005 made part.

Looking thru my records, this is my third AS module. One I ordered from a USA supplier, and the remaining two from Jaguar directly. Since I can’t seem to find an epidemic of replacement AS modules going bad, I will assume that I am the culprit, as I have just lazily left them sitting there horizontally after replacement, instead of securing them vertically to their bracket. This surely caused unnecessary stress on the part as it flopped around the car at turns and bumps.

 

spikepaga,

A couple of thoughts:

- In theory, it shouldn't make any difference whichever way the A-S module is sitting. If you take it apart, you'll find it it's just a circuit board with some capacitors on it. Horizontal or vertical alignment, or even if it's flopping about, shouldn't really affect the voltage signals at all.

- The fuel gauge fluctuating on some bends and not others is probably explained by the way in which the fuel moves in the tank and whether that really affects the relative height of the sender float.

- Silly question, but when you ran with the terminals bridged, you did have the A-S module completely removed, didn't you?

- As regards whether a "new" A-S module will be better than your old one; the common failure point of these modules seems to be the capacitors leaking. I don't know whether old but unused ones can also deteriorate in this way or not. If you know of anyone who's handy with electronics, you might ask them to check the capacitors for leakage.

- The other way you can check the effectiveness of the module would be to measure the voltage on the input and output pins whilst the module is in situ. You might then establish whether the module is "leaking" and could also check whether the input voltage is as expected from the sender. (I'm not sure what the figures should be for various positions of the gauge.) But if you really wanted you could try applying differing voltages directly to the output side and see what the gauge does.

Good luck

Paul

 

Thanks Paul. Now that I have a new one coming in, I feel fine about taking the existing one to someone who can work on a computer board to see if its
fixable, although it’s technically still working.

 

Just for anyone interested, the new AntiSlosh modules Jaguar Heritage is selling are totally different from the previous on the exterior, and are clearly recently made. The exterior material is not a hard plastic but rather a felt material. Hopefully they have upgraded the internals to make sure they last longer now.

 

Did it fix your problem?

 

Hi there, my fuel gauge problem was a wandering gauge from 3/4 full dramatically going to empty after using about 5 gallons of fuel. First I replaced the slosh model. No change. Then I had a mechanic replace the sending unit. Now, it reads empty when full and moves to full when empty and does so in an orderly fashion. Any thoughts?
'93 4.0 built in September '92

 

Should be a simple fix. The positive and negative wires to the sender are probably misplaced. Also, replacing the sender is one of the easiest things to do on this car if you can get over the fuel smell. You probably want to remote your battery and make sure your tank is as empty as possible

 

I switched wires on the sender, and found it made no difference to my gauge. I'm not sure that will resolve your problem, but am interested to hear back!

I believe I have to go into the back of the gauge for some cleanup...if I do that, I'm going armed with LED bulbs for the instrument panel!

 

Should be but not to be. Reversing the wires was my first thought as well. I reversed the wires and still get the same reading just below full when it should read just above empty.