Was thinking about getting both codes and have convinced myself that I need to replace the top and bottom O rings on each injector. Not having any fuel leaks, but the bottom O ring may not be sealing now that I have distributed all of them and reused them. Found an O ring kit online, ordered it along with a new fuel filter (that I have never replaced; not sure if dealer did). Perhaps by replacing the O rings and inlet screens along with the fuel filter, maybe, just maybe, I will solve the lean codes.
Will be next weekend before all parts are here; will update with my results.

 

The Latest:
I replaced the OEM fuel filter....sure thought that had been replaced....have not opened it up yet, but am sure it is going to be dirty.
After checking for fuel leaks at the new fuel filter, there were none, cleared the P0171 & P0174 codes. Then took out for an easy drive.
Did two re-starts during the trip of only about 2 miles....and of course ON comes the CEL and Restricted Performance message.
Got home, pulled codes and only have P0171 now.
Got my propane torch out (not lite...not yet anyways), the engine at idle, low flow of propane, went around the throttle body gasket, breather/crankcase vent lines, intake at fuel injectors.....no change in RPM.

I replaced the intake gaskets about a year ago when I replaced those coolant lines that are under the intake.
I am at a loss of where to go from here, except perhaps to a shop.

Any suggestions??

 

My 2002 XKR has 118k miles and it is still on the original injectors. I occasionally use STP fuel injector cleaner added to the gas.
Also I recently fitted a new fuel filter Fram G3727 which cost $9 from Amazon, and it is easy to install, located near the left rear wheel.
If you can read the datastream on your phone app (DashCmd or whatever) check the readings from the MAF and MAP sensors to see if they make sense.
With hot engine at 650rpm idle my MAP reads about 35 - 40 kPa and the vacuum is highest at idle, so pressure is lowest. Open the throttle a little and it goes up.
If yours is significantly higher it would confirm an air leak in the intake system. For reference the external air pressure is about 100 kPA

 

With the fuel rail with injectors on my work bench, removed injectors from fuel rail, then began to remove the O rings from the injectors. In doing so I broke three or four of the plastic retainers for the top O ring. I opened a new thread on trying to find replacements, so far no-go. Not able to do anything until I get replacement retainers, but once I do I plan on viewing the MAF output on DashCmd.
If the MAF output does not increase when the throttle is increased, then either there is a large air leak (non-metered air) entering into the intake or the MAF has failed.
And perhaps the issue has been the MAF all along, ???. As others have stated, you would think that if the MAF has failed, then both banks would report a lean condition....which it has only done once.
My plan is to monitor the MAF output....once I get these blasted retainers replaced. About ready to send the injectors off for cleaning and let them replace these retainers along with the O rings, filter baskets, end caps for $22/injector. Only issue with doing this is the XK8's down-time, it is a daily driver.

Oh and I agree replacing the fuel filter is not all that difficult. Should have done this years ago!!! I cut open the old filter.....full of junk!! Not sure how the engine got any fuel at all through it. I have cleaned two of the injectors myself using spray carb cleaner through it when connected to a battery. Those two sprayed OK. A rather messy job though, carb cleaner goes about everywhere!!

Thanks for the reminder to monitor MAF output.

 

Still working on this issue.
Sprayed carb cleaner through all the injectors, then installed new micro screens and O rings, but still no plastic retainers for the top O ring.
Decided to purchase a set of re-manufactured injectors. Afterwards I finally found the plastic retainers, ordered them as well as another rebuild kit as the first kit I purchased did not have the correct bottom O ring.
The re-mad injectors arrived. They looked good, nice and clean, correct size O rings, so I installed them.
The engine started, had a very rough idle and seemed to be misfiring. Went out for a short drive to see what happens.
Never got better, upon return home, CEL with codes of random misfires, individual cylinders, and lean both banks.
Thought about doing a hard reset and trying again, but the 2nd injector rebuild kit arrived, so I removed the re-man injectors.
Installed the kit into the OEM injectors. (Side note - getting those micro screens out and new ones in.....geeze!)
Put the OEM injectors onto fuel rail, then everything back to the XK8.
Cycled key three times to get fuel and pressure back into fuel rail. Started engine, nice smooth idle, no fuel leaks. (Will be returning those junk re-man injectors)
Took out for a short drive of about 20 miles, no CEL, no Restricted Performance, all was good.
Returned home, connected scanner and had P0191 - fuel rail pressure sensor fault.
Have checked the vacuum hose and electrical connector going to the pressure sensor....did not see anything. Will drive again, see if it returns.

Perhaps the P0171 / P0174 were caused by air being sucked in around the fuel injector bottom O rings or perhaps the injectors needed cleaning.
Will update again after a few more drives.

 

NOPE....not the solution.
Fuel pressure is steady at 55+/_ 1 psi. P0191 went away....have P0171 & P0174 again.
Used to be just P0171, now get both. Going to replace the MAF.

 

Need to make a correction: Jaguar does not use the term "MAF", uses air flow sensor. In all my posts above, MAF is really the air flow sensor.

And after several days of checking, now getting both P0171 & P0174 every time, decided to replace the air flow sensor. Ordered an aftermarket one from SNG Barrett as it was in stock and less than half the cost of an OEM one.
Prior to replacing the air flow sensor, I wrapped some Teflon pipe tape around the O ring area of the air flow sensor to make a better seal; just in case this was the air leak. Still got the same two codes, so I went ahead and replaced the air flow sensor. I did a hard reset and then started the engine, monitoring fuel trims saw both banks were below 10% for both short and long term. Have not seen those levels since I started this.

Took out for a 30 mile drive and all was good, no CEL, no Restricted Performance. Returned home, got the scanner going and once again the fuel trims all look great.
Not calling this fixed just yet, need more miles, start/stops before I do that.
Will update soon.

 

Well done, keep us posted....

 

Hi Lanny,

Congratulations on your resolution of the lean codes!

In Jaguar service documentation, the terms Mass Air Flow Sensor (MAFS or MAF Sensor), Mass Air Flow Meter (MAFM), Air Flow Meter (AFM), Air Meter (AM) and Air Flow Sensor (AFS) are used interchangeably. You will also find references to the "hot wire sensor" or "hot wire probe," which also refers to the MAFS. Here are just a few examples from X100 Workshop Manuals and parts.jaguarlandroverclassic.com:







Cheers,

Don

 

When I went looking for a replacement MAF / air flow sensor, I did not get much using MAF, but I did when I used air flow sensor....IDK???

Another 30 mile drive today, two start-ups with about an hour in between them......and still looking very good. No CEL, no Restricted Performance.

I did get the low fuel indicator for about 10 seconds on first start-up. Odd as the fuel is not low and it went off and never came back on. In fact, I have never ever seen it on in the 15 yrs we have had the XK8. I had to get the manual out to see what it was.......another IDK???

 

Most parts suppliers list them as Mass Air Flow Sensors, not MAF Sensor or MAFS, which is probably why your search string of "...air flow sensor" was more successful.

Cheers,

Don

 

Well.....another week of driving the XK8 with no issues.....calling it FIXED!!
Only change that we noticed is that on a cold start, the idle is just a bit rougher than it used to be. But it smooths out as soon as the fast idle drops out, then all is the same as it used to be.
Still need to take the XK8 out for a long drive on the highway to burn-off some of the extra carbon deposits caused by the rich fuel mixture over the past weeks.
But still calling this FIXED!!

 

Not so fast......after 2.5 to 3 weeks, going down the highway, could only get to about 45mph, got off and got about 1/4 mile and engine stalled.....and that was it. It would not re-start.
Pulled codes....multiple misfires and air flow sensor circuit open.....the after market air flow sensor has failed.
I installed the OEM that I took out, engine started and I got it home with no problems.
Driving around locally, no CEL, but highway and needing to get up to speed quickly and the CEL returns....codes of P0171 & P0174.
SNG Barratt is supposed to send me a replacement under warranty. They do not have one in New Hampshire, have to get it from UK. That is going to take a while.
Wife has had it....get rid of it!! She is looking at new cars.

 

I know I'm resurrecting an old thread here Lanny. Did the wife win, are you Jag-less? I really felt for you reading your story. I've owned my XKR 2003 for 17 years of enjoyable mostly trouble free motoring bar the odd lamda sensor replacement by my (not very local) independent Jag specialist. But now as of last week it seems I've finally reached the point of brittle vacuum hoses and chasing fuel trims and P0171 Bank 1 lean just like you were. I've smoke tested, brake cleaner tested and identified 3 leaks so far. Today's find was a typical rollercoaster: hang on a minute this 'PCV' seems to have the same lack of resistance no matter which direction I blow through it... that's bound to impact Bank 1 air:fuel ratios!! Yes! <A few minutes of Google-Fu later> oh damnit that isn't really a PCV at all its an oil separator... not my smoking gun then... on we go. Hmmm I don't like the look of the fibreglass heat shield above the EGR transfer pipe, lots of it missing now... and that heat would play onto the Bank1 crankcase breather pipe above it which has its own 'thermal sock' on it.. a combination of thermal insulation inner and tin foil outer... lets get it off and check it over.. <quite a few minutes of swearing at very stiff quick couplings later> .. well this pipe passed various smoke tests so probably not the culprit... but lets hook it up to the pump anyway and... eureka! The inside of its corrugations are shot in the area it was getting baked by the EGR transfer pipe.... this surely is going to be my culprit... time to order another. 4 hours of interweb hunting later I still haven't found a part number that produces an image that is an exact match... and these corrugated horrible plastic pipes (designed for cable routing do you think??) do not bend so I have to get it right. Bah! I've ordered one for a Range Rover that is the ONLY one that matches what I've got (who knows.. maybe a previous garage pulled this trick and that's why I can't find a match). So now I'm in that horrible wait period... the part will arrive and won't fit. Or it will fit, and I'll go for a drive and see no MIL or codes and get hopeful. And a few hours or days later my spirit will get crushed.