Hello all.

Any leads on 2003+ Jaguar XKR??? 4.2 SC

​​​​I'm wondering if anyone has found an aftermarket alternative to the $14million dollar C2N1147 part, with all the new plastic - and everything else. I don't need all that. Just a the pump.

 

I searched for a while and had to make do with the $14 million dollar part. I couldn’t find anything aftermarket. It is a returnless fuel system and that greatly limits the pumps you could Frankenstein onto the module. SNG Barratt sold me the pump at $712 + shipping; it was the lowest price I found for a new OE pump. I had to wait a week due to the backorder.


If your car is a coupe, you can remove the subwoofer and do the job through there, although it takes Dentist’s hand skills to do it that way. If yours is a convertible you are going to either have to remove the tank or cut an access hatch.

 

Thanks Brother... I already cut the hole, lol... I have an XK8 convertible and always new this would be the route I would go to do fuel pump stuff. Just never needed to.

Now,,, I'm working on a 2003 xkr that was flooded... The car sat and sat,,, gummed up the fuel pump. Strangest thing is I get a + positive reading from both lines going to the pump, there's no negative lead. Is that normal?

Anyways,,, I'm emailing back and forth with Walbro now to see what they recommend. I don't care if the pump fits perfectly into that plasitc contraption back there, it sinks. I'll secure it into the bucket and twist it down into the catch.

Lol,,, I'm tempted to take a pipe fitter and cut the little tube in the bottom of the tank as close to the floor as possible and wire up a good old fashioned external pump, powered by the fuel pump pressure regulator/control... This is nutts. Thing is, I can't figure out the powering of the pump AND which pump to get to replace (if I need to) the one I have.

Suggestions? What's with the powering?

 

Have you tried to free it up? Disassemble as much as possible and soak it up in injector cleaner? Open the body as little as possible to try and force it to spin? I did that once on a another car and it came back to life just fine. Once there was spin, there was flow, and the cleaner did its thing. The gas residue seemed like tree sap. Super sticky, but manageable. May have to do the same to the relief valve, even the injectors...

 

All very good points, Man... I did. Was afraid to take it much apart but I took it completely out of the bucket,,, poured some Birkable 2+2 gum cutter, them some WD-40 and Marvel. Messed around for a while, got it to spin once and then it stopped. Hasn't gone around again since... I'm mostly stumped on the positive voltage on both leads going into it from the damn FPCModule... Got to feeling like I was bench testing wrong...

I'll buy some fuel injection cleaner and soak it overnight and see what happens.

 

Remember, this pump is controlled by PCM, this is not going to be 12V all the time. I''d say leave it to soak in injector cleaner at least 24 hrs before giving up. Make sure all rubber is off because it would swell.

 

Positive on both sides of the pump is normal. As stated earlier, it is a returnless system and as such the pump is a variable speed type. The control module downstream switches the ground on and off in a PWM way to control the speed.

 

So thats normal,,, a fact... Great to know... I was stumped with this "problem" all weekend. In that case, how can you bench test a pump like this to run the crud out? A negative lead to the body of the pump? To the car?

Just to know/understand (if I ever will) is there a ground in that other bundle and wire connector (the black one) that seems to deadens in the top of the housing and on the underside? Is the tank the ground?
​​​​

 

In the mean time, is there a variable speed fuel pump that anyone has come across. I don't care if it fits perfectly in the bucket. I can figure out how to keep it on the bottom. And, will I need a pump that has two positive feed posts?

 

Just got 40oz of injector cleaner and a good container for the soaking. Thank you, Mertz!

 

Just got home to SOAK the old OE fuel pump and noticed it's clearly marked VSO positive and negative on top. Yup,,, still confused...
I understood it to be TWO positives (wires) connected to the pump. Just like the two positives I have, with the Fuel Pump Pressure Control running the ground away from the unit? I'm sorry but I don't get it.. In theory I understand... But what I have are TWO positive wires/leads that I would need to plug into a pump marked +/-....

Makes it impossible to think about finding a aftermarket alternative.

​​​​​​​Oh my aching head, lol

 

You don’t have two positives, you have a circuit that is connected to +12 on one side and nothing on the other side.

Connect negative side wire to ground, pump spins, no more to it than that.

The pump doesn’t normally stay at full speed for long and I can’t say if running it like that for extended periods would overheat it.

 

The point of Pulse Width Modulation (PWM) is that you can take a normal device that takes a simple supply of voltage to do a simple on/off thing and "mess" with it by quickly turning power on and off for the purpose of obtaining variable behavior. A completely full on fuel pump would supply a certain volume of fuel at a certain pressure. But if you start pulsing the power, you can get any pressure you need (up to that max) by controlling the pulse, basically how long it's "on" vs. how long it's "off". In this setup, the PWM is driven by the fuel pressure sensor on the fuel rail.

 

When I opened this fuel pump assembly, there were 2(two) wires attached to the top of the fuel pump. One was clearly marked 12v... The other marked negative or ( - )....

At this point, maybe something will change, when I restore, replace, the two connections as they were,,, I have voltage (using a test light) coming into both positive and negative terminals on top of the pump. Positive reading at every plug and connector from the FPM to the pump... The pump is not operating. That's what I got.

Now, I could go over near the FPM and snip the wire connected to the negative terminal down the line and ground it,,,, but that is not the design or how I found it...

 

Great Mertz,,, thank you for the explanation!

Now what do I do about the fact that I have positive voltage at both terminals going into the pump?

Also,,, the thread question,,,, do you know if anyone has found a suitable pump to that can be fit and used with the bucket in the tank? Will any pump work or does special consideration need to be taken with the fact that it is a returnless system and variable/alternating current?

I've been looking at the Walbro 255L... Does anyone have any experience with these,,, or others?

 

That is exactly what you have to do if you want to bypass the pump control box and run the pump manually.

The pump control is like a light switch. The ECU tells it to switch on and off very rapidly at some "duty cycle" based on the amount of fuel needed. If the switch is on 50% of the time, the pump runs at 1/2 speed. If it is on 25% of the time the pump runs quarter speed.

Your car is not running, so the ECU is not telling the switch to be on at all. Voltage is supplied to the pump all the time but the minus side is an open circuit.

 

CC... When the key is off,,, no power to the pumps or the FMP. When the key is turned to position 2 (ii) there is power. Power to BOTH the YR and the R wires (see pic) feeding directly into the pump. The pump is not running at this point. Neither line, connection, circuit is "open". They are both live.

Q: Does it HAVE TO BE,,,, MUST IT BE,,, a pump that is specifically designed to work with a pulse modulating system or can it be any ol pump that runs on 12V? I am "testing" with a pump from an XK8 with the 2 pump system. Hence the question,,,, are there any pump alternatives know for the XKR so I don't have to spend 8million dollars for the whole basket, and crap...

I don't want to snip the wire and ground it. I want to get it, to restore it, to as designed. That is what I am trying to get help figuring out...

 

Your "problem" is that it is functioning exactly as it is designed to function. Single ended fuel systems like this do not run the pump all the time whenever the key is on like the old return style do.

I will try 1 more time to explain what is going on...

Inside the pump module:
BT18-5 is connected directly to BT18-1 ALWAYS

A motor is just a really long wire (plus some magnets) so with the key on you will see +12V on the entire circuit, BT18-1 all the way through the motor up to BT18-2.

Inside the pump module again:
BT18-2 is NOT connected to BT18-6 UNLESS the ECU applies an input signal to BT18-3 and BT18-4

The open circuit I am talking about is the connection between BT18-2 and BT18-6. With key on and engine NOT running then this circuit will not be grounded and no current will flow through the motor.

How about this:
Unplug the pump module completely.
Connect +12V to BT18-1
Connect BT18-2 to ground

Now the pump will run at full speed without the ECU control input.

 

According to JTIS you should have +ve battery power at FK04-2 and ground at FK04-1

 

Fulton,,, I understand and can appreciate your frustration with me. I was a chem teacher for many years and occasionally, when giving students or a student information they had never been introduced to before, I would get frustrated, and have to catch myself... I had to remember that this was not simple **** I was giving them and they had never heard it before.... Anyways...

I have positive voltage, at any point the key is on, from both wires coming out of the FPM going towards the fuel pump.

I just ordered a Walbro 255LPH as recommended by a Walbro rep... I think, just to get fuel to the rail, I will take your suggestion to ground it. I don't want to burn it. But,,, at first, I may snip one of the wires in the circuit and ground (and I have to double check which, the R or the YR is going to the ground on the pump) the line coming from the ground terminal on the pump and see if that gets the pump turning. If not, I'll direct feed it somehow.

Me, I have never gotten a test light to light both wires going INTO an appliance... New for me. Now, with things the way they are (I will go measure with a multimeter the voltage on the lines) I have indications of 12volts on both lines coming out of the FPM with key at ii going INTO a pump that has never turned... With this the pump has not run, ever. On cranking, never - this - on a tested working pump or the old gummed pump. That confuses me.

What I understood, that on key turn, the pump would run a two second prime. I do not get this 2 second prime with a working pump. I have the tank set up in a way right now (I cut the back shelf) that I can hear it, and access it during tests. I can hold it in my hand when cranking. After cranking, I have no pressure and have never had pressure in the rail. Not once. So yes,,, bare with me if I am a little confused.

​​​​​​I will go back to it and give it a shot... Thanks for your help...