Hi Guys!

Just took the XKR to the mechanic after it started to hesitate on my way to work. I have been having on and off again issue with the car starting to stumble sporadically and twice it was the supercharger seals and I could hear the vacuum leak. This time, there was no hissing sound but I did hear the weird sound almost like rocks in the supercharger which happened the other times. The car was basically experiencing a major power loss when I stepped on it and I briefly saw the CEL flash so I limped home and it was idling pretty rough.

Had it towed to the mechanic and went back today to pick it up. They replaced the mass air flow sensor and an ignition coil as well as took the supercharger apart and put it back together to inspect it. Car was idling and running fairly okay but when you hit the gas there was definitely a major power loss. It would happen around 4000 RPMs but there were no CELs or restricted performance warnings coming up. The mechanic does not seem to know what the issue is but he suspected it was one of the two fuel pumps. I told him the car had only one fuel pump and he called Jaguar on speaker firm and was surprised when they confirmed that it only has one. He told me that it was reading around 40-50 PSI normally and then dropped when he hit the gas which made him think that one of the pumps was out and perhaps he is right that it is the pump causing this issue. I can confirm that I could use a new pump as I have to cycle the key to prime the system if it has sat for a while likely due to the fuel lines losing pressure as gas seeps back into the tank on the single line. I had read earlier that there is a common issue with the single return line fitting at the pump going bad causing a loss of pressure requiring the key to be cycled. Before this recent incident she ran smoothly at idle all the way up to WOT once she was turned on so I figured the pump was doing its main job but obviously could function better.

My question is, do you guys have any suggestions on where we might start since it will be somewhat of a crap shoot. I know that I need to replace the fuel pump at some point due to the cycling requirement but I have lived with this for some time and want to focus first on getting the car running properly before doing this. It could very well be the pump but my research indicates that it could also be:

• fuel filter
• fuel pump controller
• fuel pressure sensor
• MAF (replaced)
• TPS
• Injector leaks/issues.
• Ignition coils (they seemed okay and mechanic replaced one)
• Bad plugs (replaced them two months ago)

One other issue that could be related but I was thinking was unrelated is that periodically the p0456 code is thrown (small evap leak). Have read that that is likely a bad gas cap or EGR valve.

Any help and suggestions would be greatly appreciated! I am really concerned about blindly replacing parts and trying things as I do not have endless funds to invest in the Jag and I am a little concerned about the credibility of my mechanic. They are great guys and I enjoy working with them but there have been too many instances where I have corrected them on how this car is set up and how it works thanks to these boards and the fact that I can focus solely on one make and model and they work on so many other vehicles so I do not expect them to know the 2003 XKR as well as I have come to know it.

Thank you all for your help!

 

It sounds as though your #2 fuel pump is not working. The XKR uses 2 fuel pumps in the tank. Pump 1 is for normal cruise efforts. The #2 or secondary pump kicks in when RPM is in the 3500 to 4500 rpm range under acceleration. The rattling is probably engine ping because the knock sensors and ecu can't control it without the added fuel.
Try starting the car normally and warming it up. Then shut down and pull the Pump 1 relay from the fuse box in the boot. Then try to restart. Does it start up and die then won't restart without placing the Pump 1 relay back. If so your #2 pump may be dead. Before condemning it swap the #1 and #2 relays. Does the engine start and run? If it doe's then the pump is most likely bad.
Do to the effort of removing the fuel tank to replace the pump you might consider replacing both while your in there.

 

2003 4.2L XKR? Definitely just one fuel pump. As you pointed out, return-less system. Fortunately, the fuel pressure is available over OBDII. Should be 55 psi all the time. A cheap ELM327 can get that data, and a phone app like Torque can record it as you do a power run (keep your eyes on the road). If the pressure drops with flow, I would start with the filter. Actually, if you do not know the history, change the filter. Next, check the fuel trims. They are a function of RPM and load, so the recording function would help there, too. If you see the trims go way up with load/rpm, then it points to a restriction again. Also, be sure to double check the air flow meter for the correct DENSO number. Lots of them fit, even the plug, but are not functionally equivalent.

Best of luck, keep us posted.

 

^^ What he said....

These fuel filters can really load up with junk and restrict fuel flow (and cause the fuel pump to have to work extra-hard). I changed the factory fuel filter on my wife's 2006 XK8 (it was stamped "April 2005") at 90,000 miles. Judging by the nasty grey-colored fuel that spilled out of it upon removal, I immediately decided to set my fuel filter change interval at no more than 40,000 miles....

 

Thanks for the suggestions. I am absolutely going to replace the fuel filter and will go to the auto parts store to try to find the ELM327 otherwise I see it can be ordered on Amazon and will arrive Monday. As for the MAF, this is the second time they replaced it but I just found out yesterday that they were using used parts from a massive part inventory they have. Would not be surprised if it was the incorrect MAF if many others fit. Ha also wouldn't be surprised if it was a non-working MAF as well. So to start, I am going to have them replace the fuel filter and then I will take it from there. Will keep you posted and thank you for helping out, very much appreciated!

 

Thank you for commenting Avern. That totally makes sense and is exactly what the mechanic thought but there is only one fuel pump on the 03 XKR. Will keep you all posted on how this all ends up.

 

Good to know! This car has 82k on it and I doubt the filter has ever been replaced. Do you recall if it is a difficult job? I have done a bunch of work on the car myself in the past but lately have been short of time plus my attempt at the valve cover gaskets did not go too well hence bringing it in to the shop. In fact, the car has had constant issues ever since that fateful VCG job. Thankfully, it has run very well for periods of time inbetween the issues so I have confidence we will be back up and running soon.

 

The job is easier if you have tiny Trump-like hands (my hands are massive so I had a bit more difficulty). Jack up the rear end enough to gain working clearance, pull the left rear wheel, get on your back in the wheel well, look up, follow the fuel line hose, and you will see the black metal bracket that holds the fuel filter to the body. Just be sure to have the correct fuel filter on hand before you begin. For our 2006 model, the fuel lines clip onto the fuel filter inlet and outlet tubes (they do NOT screw on). You have to know how to press the tiny white tabs on the attachment clips with either your fingertip or a small screwdriver in order to release them. If I remember correctly, I removed the bracket, then removed the filter from it. That gave me more working room and I had a better chance of actually seeing what I was doing. My fingertips were far too big to be able to release the white tabs, so I wound up using a small screwdriver....

 

And don't buy a OEM filter. There are many quality filters for $10-15 at the parts stores or online.

 

Hey Guys,

Just wanted to provide an update and solution to the issue. As it turns out, it was the MAF sensor all along. The mechanic did not think it would be the fuel filter and suspected that the used MAF might be bad. I purchased a new one on eBay for only $120 and when I put it in the car ran great. Apparently, either the sensor was bad or it was not the correct sensor. Amazing how such a severe issue can result from a mere sensor. Glad to have her running smoothly again and I am going to replace the fuel filter and pump in the near future for good measure. I already know I need to repair or replace the pump as it is not holding pressure when I turn the car off. I have to cycle the key in the ignition a few times before starting. Other than that, the pump works fine. I recall Reverend Sam posting something about repairing the pump where the fuel line is connected as there is a plastic clip that can go bad causing fuel to back into the tank when the car is turned off. Debating giving that a shot although it is a lot of work to simply get to the pump and at that point it might make sense to replace it altogether.

On an unrelated note, had my first green shower when I used the car for the first time yesterday. Ahhh.... the joys of Jaguar ownership :-)

Thanks,

Corey

 

Sorry to hear about your green shower. As you probably already know, the folks at Top Hydraulics in Washington state offer far superior convertible top hydraulic hoses than anything installed at the Jaguar factory....

 

Great, thanks for pointing me in that direction. There was a place by me in Bradenton Florida that I found on eBay selling a kit for $640 with upgraded pressure capacity of 27500 psi versus the 1900 of the original hoses. Do you know how Top Hydraulics compares to that?

Thanks!

 

Not sure what the Top Hydraulics pressure ratings are. I would contact them and ask....

 

Top Hydraulics hoses are 23200. I have not heard of a hose failure, and even the OEM just seem to fail at the fitting. I have used them on a couple of cars.

 

 

Adding to the use of "correct" MAF sensor. I tried an aftermarket and had loads of issues (actually threw OBDII codes saying bank 1and bank 2 running lean). I bought an OEM and installed it, issues went away. Lesson learned: buy OEM when you can. Others fit but might not function properly.