XJS ( X27 ) 1975 - 1996 3.6 4.0 5.3 6.0

Fuel Pump Dilemma

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  #1  
Old 07-19-2018, 02:13 AM
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Default Fuel Pump Dilemma

Hi Guys

I am about to put a New Fuel Pump in my XJS 4.0L Celebration Convertible which has an In-Tank Fuel Pump

An OEM Fuel Pump for this Car is around £100 while one from a Ford Sierra is about £15 and they both look almost identical, as do many other Ford In-Tank Fuel Pumps

These New Ford Fuel Pumps come with a Wiring Harness, which is basically a Plug that goes into the Fuel Pump with a couple of Wires coming out of it to accept whatever plug you want to put on the end of those two Wires

As for me I can't see any point in Spending £100 on a Fuel Pump if a £15 Ford Fuel Pump will do the same job, where the only problem I can see is finding a Plug (The White one in the photo) to go on the end of the Wires of the Ford Pump

Does anyone know the name of this White Plug so I can get one on ebay or could I somehow take the White Plug off the Fuel Pump and re-use it

Just in case you were wondering the Plug on the other end that goes into the Ford Fuel Pump also looks different, so I can't just swap the harness over and re-use it on a New Ford Fuel Pump

Any ideas?



Jaguar Fuel Pump with 'White Plug' that goes into the Socket of the Round Evaporator that fits onto the Top of the Fuel Tank with a Sealing Collar



Where can I get a 'White Plug' like this to go on a Ford Fuel Pump which looks exactly the same apart from the Plug and the Price!

 
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Old 07-19-2018, 03:25 AM
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Why not just cut the plugs off, leaving plenty of wire on the one you need, and then just strip the ends and join them, and then heatshrink an outer cover on them(having threaded it on first of course!)?
 
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  #3  
Old 07-19-2018, 04:29 AM
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Hi Greg

Cheers!

That thought had also crossed my mind but those Wires from the Fuel Pump 'Unbelievably' come into Contact with Petrol and with a Full Tank of Petrol may be Totally Submersed in Petrol

And so if any Petrol makes it past the 'Shrink Wrap' then it could be 'Kapow!' in a big way! as you could then be putting 12 volts through neat Petrol

I still find it very hard to believe that these In-Tank Fuel Pumps are Safe, as unless anyone knows different, all you would need is a break in a Wire and then it could be 'Game Over'
 
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Old 07-19-2018, 05:13 AM
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You can put current through neat petrol all day long and nothing will happen! It's when you have a mixture of fuel vapour and air that you have a problem, and even then you need a spark, not just a voltage. Shrinkwrapped joints will be fine.
I'd be more concerned about being sure that the Ford pump flows at the same rate and pressure as the Jag pump otherwise you'll have fuel starvation.
 
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Old 07-19-2018, 06:38 AM
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Hi Bladerunner

That is very interesting, you learn something new everyday and so it looks like 'shrink wrapped joints' will be the way to go, with the Wires Soldered together to prevent any Sparks

Thanks again it looks like problem solved
 
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Old 07-20-2018, 01:20 AM
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There was no response to Bladerunner 919 comment about flow rate and pressure. Are the pumps interchangeable?

In this respect is there a list of interchangeable parts from other automobiles?.
 
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Old 07-20-2018, 02:52 AM
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Hi Afterburner

That is a very good point!

The Pump I am thinking of buying is 120 LPH do you or anyone know if that is enough?

Also its not compatible with an XJS which could be solely down to the shape of the electric plug, which I may have to mod

I've bought loads of stuff which is not compatible with an XJS including the Fuel Pump which is on my V12 which wasn't supposed to fit although it did

And only cost me a fraction of the OEM price and is still working A1 after 3 years of use, as a lot of these pumps are generic and as such were fitted to lots of different cars
 
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Old 07-20-2018, 03:43 AM
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OB
I think the spec is for 180 l/H at 3 bar, so this might be a bit too low a flow rate.
 
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  #9  
Old 07-20-2018, 05:44 AM
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Is there a way to convert the faulty fuel pump into just being a fuel pickup, and mount an external fuel pump? I think I'd be tempted to look at that to avoid having to pull the tank ever again.
 
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  #10  
Old 07-20-2018, 07:35 AM
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Originally Posted by bladerunner919
Is there a way to convert the faulty fuel pump into just being a fuel pickup, and mount an external fuel pump? I think I'd be tempted to look at that to avoid having to pull the tank ever again.
In theory,,yes, you could but you will want to keep the hose or pickup mounted in one position to keep ot sucking correctly... The outside pump XJ-S have the swirl pot and a low take off central tank output which gravity feeds into the swirl pot. This is all long gone on the in tank models.

@OB

No need for a Ford pump. They are just generic. Volvo had the intank pump long before Ford bought them. And Jaguar as well, as the XJ40, built 1985, had the same tank as the late X308 models until 2003. All with an in tank - NON Ford - pump.
 
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Old 07-20-2018, 07:36 AM
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Hi Bladerunner

You've just been reading my mind!

As over the last couple of Weeks, I've been toying with the idea of doing exactly that because those In-Tank Fuel Pumps are nothing but a problem, as they are nowhere near as substantial as the Pump on a V12 which I could easily change in a couple of hours

Where changing an In-Tank Fuel Pump could easily take you a Week because in order to get to it, you have to strip the Boot/Trunk of all the Interior Trim and even worse on a Convertible as the Hydraulic Pump has to come out

And even the CD Changer which was only just a fraction in the way!

At the Rear of the Fuel Tank is an Inlet and Outlet, so all you would really need to do, is to blank off the Big Hole in the Top of the Tank with the 'Evaporator' which is already held in place with a Locking Ring

And then just Run a Fuel Pipe to the Engine with a V12 Fuel Pump, somewhere in that Line

As for the Return Pipe that's already there! and ready to be plugged into the Tank like it would be with its normal Set Up

So basically all you would need to do is to get one Fuel Pipe Made with a V12 Fuel Pump in the Circuit

On Paper it would be a Breeze (What do others think?)

A Couple of Questions:

Would a V12 Fuel Pump work or would it be too powerful for the 4.0L Six Cylinder Setup

Would the existing Relay Setup Work? (I can't see why it wouldn't)

Would I need to fit a Sump Tank or could I do without one?

Could I use Rubber Fuel Pipe all the way through?

Comments and Suggestions would be very Welcome
 
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Old 07-20-2018, 07:52 AM
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That is a ton of work to replace the fuel pump and you want to gamble on a "similar" pump? My hat's off to you, but damn that 85 pounds in savings is going to look pretty meager if something doesn't go as planned and you've got to do it again.

I've always been tempted to cut an opening in the floor of the trunk and see if i can make an access point from above. This way, if it ever needs to be serviced, then you've got an easy way back in. If you can figure out how to make an access hole work, then the Ford pump sounds like a viable plan.

BTW, not only is gasoline itself not flammable, just the fumes, you need a somewhat precise ratio to set it off. Would you believe the range is only between 1% and 7%, any more, and there's not enough air for the burn to begin!
 
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  #13  
Old 07-20-2018, 08:24 AM
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Originally Posted by orangeblossom

A Couple of Questions:

Would a V12 Fuel Pump work or would it be too powerful for the 4.0L Six Cylinder Setup
Same pump for both from the factory so all good

Originally Posted by orangeblossom
Would the existing Relay Setup Work? (I can't see why it wouldn't)
yes, no probs
Originally Posted by orangeblossom
Would I need to fit a Sump Tank or could I do without one?
Interesting point. I have a feeling the WoZ did away with it on one of his cars, but was careful to keep the tank 1/4 full. It is slosh onb takeoff and hard cornering that will starve the pump, Myself, I would put one in, plenty of room in the boot. Loads of "swirl pots" (what the racers call them) available and nice ally and cheap.
Originally Posted by orangeblossom
Could I use Rubber Fuel Pipe all the way through?
Under the car, connect to and use the OEM pipes. In the boot, high pressure fuel injection rubber pipe and jubilee clips will be fine.

It is always a lot of work changing things though, and 90 quid buys you a new one from Manners, and all good for another 18 years. But as Vee says, if you can pull the tank and make an access hole on the parcel shelf, then that would be a great mod!

 
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Old 07-20-2018, 08:39 AM
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Hi Greg

How is the V12 Pump the same as for a Six Cylinder?

The V12 Pump is external and the Six Cylinder Pump is an In-Tank Pump, so not quite sure what you mean?
 
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Old 07-20-2018, 10:17 AM
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Originally Posted by orangeblossom
Hi Greg

How is the V12 Pump the same as for a Six Cylinder?

The V12 Pump is external and the Six Cylinder Pump is an In-Tank Pump, so not quite sure what you mean?
The later V12 pump is in the tank.
 
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  #16  
Old 07-20-2018, 10:20 AM
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Originally Posted by Daim
In theory,,yes, you could but you will want to keep the hose or pickup mounted in one position to keep ot sucking correctly... The outside pump XJ-S have the swirl pot and a low take off central tank output which gravity feeds into the swirl pot. This is all long gone on the in tank models.
Could you take the guts out of the pump and run a pickup pipe inside what was the pump body? That would keep everything in the right place, wouldn't it?
 
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Old 07-20-2018, 11:38 AM
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Originally Posted by bladerunner919
The later V12 pump is in the tank.
Ah! See what you mean!
 
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Old 07-20-2018, 11:52 AM
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Originally Posted by Greg in France
Same pump for both from the factory so all good


yes, no probs

Interesting point. I have a feeling the WoZ did away with it on one of his cars, but was careful to keep the tank 1/4 full. It is slosh onb takeoff and hard cornering that will starve the pump, Myself, I would put one in, plenty of room in the boot. Loads of "swirl pots" (what the racers call them) available and nice ally and cheap.

Under the car, connect to and use the OEM pipes. In the boot, high pressure fuel injection rubber pipe and jubilee clips will be fine.

It is always a lot of work changing things though, and 90 quid buys you a new one from Manners, and all good for another 18 years. But as Vee says, if you can pull the tank and make an access hole on the parcel shelf, then that would be a great mod!
Hi Greg

(1) No Parcel Shelf in a Convertible, so unfortunately nowhere to cut a hole for easy maintenance

(2) Inside the Fuel Tank of an In-Tank Fuel Pump Car (at least in the tank of my Car) the In-Tank Fuel Pump sits inside a Steel Circle, presumably to prevent Fuel Starvation when Cornering

(3) I've also got a Spare Sump Tank

(4) And I've also got the Fuel Tank that goes with it from an XJS V12 Coupe
 
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Vee (07-21-2018)
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Old 07-20-2018, 12:15 PM
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Hi Bladerunner

While its almost impossible to take the 'guts' out of an In-Tank Fuel Pump, I think it would be possible to drill a hole right through it from one end to the other

But one of the major problems might be that the In-Tank Fuel Pump, sits upright in the Tank and sucks Fuel in through the bottom and then blows it out the top into the Fuel Feed Pipe to the Engine

So in other words the In-Tank Fuel Pump has to 'Suck and Blow' which obviously puts a bit of a strain on the Pump

Whereas the 'Pre-Facelift' Fuel Pump on a V12 is a more substantial unit altogether and is also 'Gravity Fed' which obviously takes a lot of strain off the Pump

So I'm not sure if the 'Pre-Facelift' Fuel Pump would be able to suck the Fuel uphill, like the In-Tank Fuel Pump has to do
 
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Old 07-20-2018, 12:18 PM
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OB your 1996 is handsome! My 1993 is black also

You might want to look at: https://www.instructables.com/id/How...ic-fuel-pump-/
AND
Everything You Need To Know About Aftermarket Fuel Pumps
 
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