Update... In my post on September 23rd, I wrote that I once again had the same symptoms that keep coming up - fuel pressure loss when the car is off causing long crank times. So I was able to get the car into the dealership again this week to have it looked at and got the car back today with another new pump just as I suspected. I talked with the tech and he said he was in close contact with Jaguar technical support and they wanted all kinds of detail about the pump that he pulled out of the car, stuff like serial number, date codes, part numbers of specific parts on the pump assy including the check valve etc, and they wanted closeup photos too. Hey confirmed that this is the most up to date fuel pump assy that Jaguar has for the 2003-2006 XK8, and they sent another exact unit to be installed again, so this indeed is the 6th pump. This time however was the first time that Jaguar told the tech that they are experiencing a high failure rate on these with the same symptoms. Jaguar supposedly is investigating this but there was no further information. The tech asked if there is anything different that can be installed, such as an old style rebuilt pump rather than these newly manufactured pumps. As it was explained to me, there have been updates made to the pumps over the years and this is the most current version. Jaguar did not want him to install anything but this same newest pump assy. The tech did mention that he suspects that ethanol fortified fuel may be a contributing factor, somehow causing the check valve to malfunction. And to be clear for everyone here, no one believes at all that this is anything other than strictly a mechanical part failure, there is no electrical function involved. Pressure at the fuel rail holds when the pump is installed, but after several weeks, when the symptoms reappear, fuel pressure drops rapidly at the fuel rail when the car is shut off. The check vavle is strictly mechanical, not electrical.

I just thought I should let you all know about what seems to be some kind of design flaw, and or manufacturing problem apparently with the check valves on new fuel pump assemblies from Jaguar, and if you have a bad pump and it is confirmed that the electric pump motor itself that is bad, you may want to consider replacing just the pump motor to avoid the issue I am having. I will continue to update this thread when or if anything additional comes up.

 

This might be a good time to buy a 2004 XK8 and wait for Jag to resolve the check valve problem or get a rebuilt pump with an older check valve.

 

I initially went with an inline check valve to fix the problem I was having (same as yours), but the inline check valve worked TOO well. It wouldn't allow the pressure to bleed off back into the tank, so if you stopped the car after the engine was hot, the fuel pressure would build up to the point that the injectors couldn't open. It would crank and crank and never start. My OBD tool showed the fuel pressure was something like 145 PSI (I forget the exact number). The ONLY way to start the car at that point was to either wait a few hours for everything to cool off, or relieve the pressure in the fuel line by pushing on the little Schrader valve on the fuel rail and allowing some fuel to squirt out all over the hot engine.

I thought about trying to rig up an inline check valve with a pressure relief valve in parallel right next to it. I never got around to doing it, though. If you are considering it, it's very easy to access the fuel line in the left rear wheel well. Keep in mind that it's a metric sized line, so you'll have to go to great lengths to make English fittings fit properly.

This seems to be a relatively common problem that many people have. Maybe WhiteXKR can market something like an inline check valve/relief valve combo.

 

Sounds lke it could be a materials problem. See if the check ***** are viton or some other ethanol resistant material.

 

I have been having similar problems over the summer. I had both the symptom described by Steve Jacks with stumbling on start, all the way to failure to start at all, but random. seemed like every time it went on the tow truck flat bed and was delivered to the dealer, it would start for them. But after about 2 or 3 days of test starts it would finally fail.

The dealer's mechanics always diagnosed the problem as the fuel control module being shorted out. The dealer replaced this module 4 time in total, the first three parts came from a warehouse in Calif. I finally asked them to source the part elsewhere. The latest part came from New Jersey (so they say) and has been running fine for about 400 miles over the last 4 weeks.

The dealer is not convinced it won;t fail again, which Jaguar tech indicated might be due to the fuel pump drawing too much juice, causing the FCM to short out. The diagnosis always indicated the FCM failed to supply ground to the fuel pump, applying an external ground to the pump resulted in a working pump, is that the job of the fuel pump check valve? or is that strictly pressure related?

Could the check valve failure cause the pump to run excessively and cause a failure in the FCM or does the check valve failure actually stop the operation of the pump? Interested in finding out if these could be related in any way.

 

I had both pumps replaced when one was found bad on my coupe. I have the usual morning 3 second cold crank time on my XKR coupe. But the opposite issue.

I have better torque now in sport mode and I feel something loose now after I filled up the tank to full from 1/4 when the pumps were replaced.

I need to have them look at it again because the coupe's tank has straps. I feel a groan or creak begind the passenger rear seat on thr left side.

Mike
'00 XKR cope.

 

The check valve has nothing to do with the ground or anything electrical on the pump. It's nothing more than a small "plug" about the size of the clicky button on the end of an ink pen. The plug fits into a hole and it's held in place with a spring. Fuel pressure pushes against the spring opening up the valve. But when the pump turns off, the spring holds the plug against the hole and prevents the fuel from going backwards.

The pump will run just fine with no check valve. The only purpose of the check valve is to prevent the fuel from draining back into the tank when you turn off the key and the pump stops running. The pump doesn't run any more or any less with a bad check valve. The only symptom is that it takes the car longer to start.

I learned that to avoid embarrassing myself and the Jaguar brand, before starting the car I could turn on the key for a few seconds then turn it back off. Then on and off again. And again, and again. Each time the key is turned on, the ECU sends a signal to the pump to make it run for a few seconds to pressurize the fuel lines. By turning it on and off I could pre-charge the lines, then when I finally cranked the engine it would start right up. The stuck up Beemers and Mercs parked next to me had no idea my car had a minor little glitch. :-)

 

I thought that since another forum member mentioned a similar issue recently and I referred to this post again that maybe it is time to provide an update on my issue. The most recent fuel pump replacement (pump number 6) was October 2012. At the risk of jinxing myself, I will state that I have not experienced any issues since. This is the longest lasting replacement I have had to date. Oh boy, I hope I don't regret saying that. Anyhow, I continue to use the car at the same frequency as I always have...I work out of the house and generally drive the car on weekends only with an occasional trip down the road for lunch or to meet my wife for dinner during the week. So, frequency of use is the same, sometimes it will sit a week without being used. However, since this last pump, I have made a point to use only ethanol free fuel. The only times I have used fuel with ethanol is on long trips where I need to fill up and am not in my local area. I always make a point to use as much of that fuel in these cases before refilling with ethanol free, and I don't let the car sit more than a day with the ethanol laced fuel...I will run it down first, then fill up with ethanol free again before parking it for the week. Again, this is the only change in my habits. I can't say if this is why I don't have any issues, or if it is finally a good pump, or some of both.

 

replying in an attempt to become a member, however the solution to your problem might be bad fuel? we see similar problems with vehicles that sit. if u go down this path be sure to clear out fuel rail as well as tank and lines. i've had good luck adding a half gallon or so of av gas to tank before letting vehicle sit. most small aviation gas stations will sell u fuel no problem if u put it in an approved container, not directly into your car.

 

nice photo

 

You may want to consider the use of TC-W3 rated two stroke oil as an additive. There are a couple of threads here and hundreds at bitog.

You can start with these two:

https://www.jaguarforums.com/forum/x...ighlight=tc-w3

https://www.jaguarforums.com/forum/x...ighlight=tc-w3

 

After talking to a friend who works for Denso I ordered Airtex pump E2471 + strainer FS175 to replace my broken fuel pump. My understanding from him is that Denso and Delphi may be the actual manufacturers/suppliers and do not market one under their own brand names (UPDATE: I HAD BAD INFO: MADE IN CHINA).

I sent the following question to Airtex tech support Sunday and received a response (below) Monday AM.

I have a 2001 Jaguar XK8 and spend considerable time on Jaguar Forums keeping in touch with other people with similar cars. My fuel pump went out and multiple people are saying they have had theirs replaced in the last 1-2 years only to have them fail within months. These are "Jaguar" pumps from the dealer I am referring to. Ethanol is suspect in the failures. I ordered your pump and strainer for my car and am wondering if I need to be careful about the fuel I use. I am sure it is designed for ethanol but would I add a measure of safety as far as longevity goes, by avoiding ethanol? Is there anything else I could be doing to help promote the life of the pump? (additives, etc?). Its a bear replacing this thing so I don't want to have to do it twice.

RESPONSE: "Good morning. We have not been hearing of this issue with our pump. One thing to consider is the length of time that the cars sit. Gasoline today is only good for about a month. After that time it starts to break down. The additives can start to separate & this can create varnish. Varnish is not good on a fuel system at all, especially the pump. We do not advocate using any type of additives but if these sit for extended periods a fuel preservative additive might be a good option.

Ethanol has been in our area since the 80's. I don't think that this is what is causing the pumps to fail quickly. We test in ethanol based fuels & have not found any problems with it.

If there is anything else I can help you with please feel free to call or email me".

 

Jacsun-
The issue discussed above in this thread was for fuel pumps in 2003 and later vehicles. You have a 2001, which is an entirely different fuel pump and does not have this issue.

I have have the Airtex pump in my 2001, and so far it has been fine. The only concern I have with it is that the hose nipple is not flared, and there is a danger of the hose falling off. I would suggest either double clamping the hose or flaring the end slightly if you have a pipe flare tool.

 

Add another checkmark to the "These cars do better if they are driven regularly" hypothesis....

 

A few years ago, both of my (original Jaguar) Fuel Pumps failed over 4 mo winter storage.

Now, during winter storage, I energize both (Jaguar Sourced) Replacement Pumps for a few seconds every 2 weeks.

I remove the Fuel Pump Relays and jumper the socket contacts to run the pump(s).

Of course, this is for 1997-2002 Cars.

 

Perhaps you could check into the fuel system winterisation routines issued by boat engine manufacturers where ethanol is a recognised problem. I heard about it a couple of days ago from a boat engine dealer and it involves .... ta-dah ... TC-W3 two stroke oil in four stroke engine fuel systems. Just contemplating which of the TC-W3 threads to pick as the place to "publish". BTW, they consider the best before date of ethanol blended gasoline to be two weeks.

 

Re ReverendSam's post having to repeatedly power the pump to allow pressure to build up-
I had that problem on my old Ford Windstar when I put in a new pump, then had long cranking. The pump only goes on for about 3s if engine is not running due to safety issues. This is normally enough to pressurize it and start. Not when it drains back. So I had to do the same thing, key on and off a few times, and I could hear the pump kind of groan when the pressure built up. Then it would start.

 

SInce there is also a pressure relief valve as you say to limit pressure, then it could also be the problem, leaking fuel back to tank. There is no return line (if system is same as my X350 XJ8) so it has to have a pressure relief in line parallel with the check valve. I think however this was mentioned at the top somewhere about the regulator being bad possibly. The other issue is, it could easily be a poor check valve batch that they all were built with, a boatload of them from China for example.