Having fuel smell, so need to get into the tank area to diagnose. While there, thought occurred to me it's good time to address old issue. Gas gauge has been inaccurate for yrs. Needle never gets to "full" point on gauge after a fill-up. So, question is this...which way do you bend the rod, i.e. raise or lower the float point? I know how the sender works...up/down, but which way makes the float register a full tank?

 

Before you do anything to the sender unit, bypass the anti-slosh module in order to eliminate that as the cause of the fault.

Cheers

Psul

 

I have a Jan '93 4.0 conv and have not heard of an "anti-slosh module". What and where, if it applies to mine. I have seen several variations of tanks depending on VIN. Not unusual for me since my build date is late 92 and has in-board rear brakes.

 

I THINK that even the swirlpot 4.0 facelift cars use the anti-slosh module.

It looks llke a large relay and takes the input voltage signal from the sender unit and then smooths it to avoid short fluctuations caused by the sender moving temporarily as the fuel moves about in the tank.

It does this by using capacitors on a small circuit board. Over time the capacitors "leak" causing a lower output voltage than expected leading to an under-reading gauge.

If you remove the module and bridge the holder across its input and output voltage terminals you'll effectively send the output voltage from the sender unit direct to the gauge.

The relevant terminals are the vertical one in the central alignment and the horizontal one just below it.

The gauge may now fluctuate as you accelerate, brake or corner, and you'll lose the low-level warning light. But you will eliminate one possible cause of an under-reading gauge.

The module is mounted on the left side if the boot quite a long way forward behind the strengthening plate. Remove the carpet trim, get a torch and mirror and you should just see it. It looks like a tall black relay.

Good luck

Paul

 

Anti Slosh module is in the left rear fender well and not easily accessed without curling up in the trunk. On my '93 built in September '92, it's kind of a one handed reach, closer to the gas tank. Should you decide you need to change out the sender unit remember that the convertible uses a different sender than the coupe. I say this from past experience.

 

Paul
THX for info. Found the "module", actually a glorified relay. Thot to do research to replace if necessary. Well... dealer priced it at $130, aftermarket online has them @ $70, but a local Hella dealer that is REALLY good did a cross from the DAC # to Standard and found it for $9! Will p/u on Monday and post pic with part # if it is of interest.
Dave in AZ

 

It is of interest, please post!!!

thank you.

 

Dave,

I'd love to hear the outcome of this! I am surprised that anyone could sell it at $9 but I'll have one if they can!

It really isn't a glorified relay. Jaguar just chose to use a relay holder and create the module with a relay pinout because it uses the principle of a voltage input with 2 voltage output circuits that could be handled through a relay holder. I've taken one apart and it uses a circuit board with a couple of capacitors to do the voltage smoothing. If someone is building them and selling retail at $9, great!!

Cheers

Paul

 

Sender update... New unit installed without issues. Prepared to install replacement anti-slosh relay after getting full tank of gas. Seems inaccurate gauge was not the result of faulty relay, but worn contacts on sender. 1st time in years I saw the gauge register "full" ! I have put the replacement relay in the "bucket o' parts" box just in case. The new relay is a Hella brand and is smaller in size, 40amp instead of OEM 30amp, but matches circuit diagram exactly and is a "constant on" type. Hella # 4RA 933.332-151.

 

92/93XJS,

Good to hear that you've got the problem sorted with a new sender. Well done.

I do need to point out that the Hella relay you've purchased is NOT suitable as a replacement Anti-Slosh module.which is completely different. That Hella relay is just a switched main current relay.
As I've mentioned the A-S module is a completely different capacitor-smoothed voltage throughput device running twin circuits, one for steady voltage output at the gauge and one for low-level fuel warning light. Its why it costs so much.
That relay you've bought will not function as an A-S module.

Cheers

Paul

 

I replaced my sender with no change in the fuel gauge... I ordered mine from RockAuto, and it was a URO labeled sender. Fits perfectly, looks identical....but no change to the problem.

 

PJTS1...Thx for the electrical details. Your understanding of electrics far exceed mine. Lucky I didn't swap it out!
What's the old line, "If it seems too good to be true, it probably is".
Dave

 

There is a 20-way white block Sumitomo connector that connects the dash with the anti-slosh module. The wiring diagram shows it as RH161 and only says that it's, "Below Lower Left A/C Outlet / Rearward Harness".

Have you come across this in your investigation? I'd like to check mine out, but am vague on where it's telling me to look.

Thanks.