Apparently then 'Too lean on Bank 1 and 2. But part of the difficulty in deciding what to do is to try to work out if this means too much air in the mixture or too little fuel.
I have done much of the usual stuff starting with cleaning the MAF and checking the weird pipe with its strange sound baffles from the air filter to the engine leaks allowing an excess of air to enter the pipe.
As I have no smoke generator i had to be flexible and being a smoker helped enormously. I put a latex glove over one end and stood in front of the bathroom mirror, filled my lungs with smoke and putting my mouth on the engine end managed to inflate the glove easily - there was also no smoke leak. So, no leakage into this pipe. The contraption also visually appeared to be in very good shape.
Next thought. The MAF should be cleaned. Initially the little glass tip appeared to be very black and sooty looking. I spayed it with
contact spray, waited 10 minutes and sprayed again. It now looked quite clean and shines but the glass tip seemed oddly caramel coloured.

Is this what the glass tip of the (Denso) sensor should look like? SEE PICS below.

BEFORE CLEANING



AFTER CLEANING


Can anyone tell if this is how an MAF sensor should look after cleaning. It looks almost burned to me!

As always, I am very grateful for any help in solving my problems.

 

MAF should never be cleaned by anything but specialized MAF cleaner. Can't really say what the appearance should be but in order to diagnose we are going to need the STFT (short term fuel trims) and the LTFT (long term fuel trims.

 

The tan / amber color is normal. But keep spraying it with the MAF cleaner. CRC makes the best one I’ve used. I had to R&R & clean mine 3+ times in the past to get the long term numbers where they should be. It looked clean after the 1st spraying , but didn’t perform correctly until after the 3rd try at cleaning.


Z

 

Isn't that bulb the intake air temp. sensor?

 

You've got me thinking.
I've done some more research and found this from Delphi

Installed in the intake pipe between the air filter housing and the intake manifold, most MAF sensors work on the hot wire principle. Put simply, a MAF has two sensing wires. One is heated by an electrical current, the other is not. As air flows across the heated wire, it cools down. When the temperature difference between the two sensing wires changes, the MAF sensor automatically increases or decreases the current to the heated wire to compensate. The current is then changed to a frequency or a voltage that is sent to the ECU and interpreted as air flow. The quantity of air entering the engine is adjusted accordingly.

After reading this and pondering anew it looks as though I will have to bite the bullet and source an inexpensive new MAF sensor in the hope that my problem then magically disappears.
Any suggestions what to look for - the original Jaguar part is simply overpriced.
Thanks to all for the helpful feedback so far.

 

Lean bank 1 and bank 2 are common problems.
there are hundreds of posts on this forum about that problem and what folks found to be the cause. Because there are a lot of different potential areas of concern that you need to look at before you start swapping parts. First thing you should do just make sure all of your O-rings on all of your vacuum lines or air intake lines are new. They tend to leak. You might have to do a smoke test on the motor with a real smoke tester that cost $20 on eBay to find other potential leaks because it could be anything from the dipstick O-ring to the oil filler cap to throttlebody gasket or the rubber coupling‘s on the air intake side. It could be almost anywhere. In my case I had a dozen different leaks. Get yourself some tool, scanner, SDD or whatever allows you to look at runtime time data because the fuel trims are supposed to change constantly as the car idles and you need to look at those to find out what levels they are at now and to make sure they’re switching properly. It also helps to be able to monitor those as you spray some carb cleaner around different ports of the engine to find leaks. Go to the Jag repair website and the help sections of this website and start learning about fuel trims so you understand how they work and then you can start diagnosing problems

 

When the tests show no leaks then I start swapping MAFS and watch the STFT/LTFT to find the one that keeps the LTFT closer to zero than the others.

I have one X308 (AJ27) engine that really liked the WALKER PRODUCTS 2451138.($30.79 at Rock Auto) I keep a new one in stock for testing/replacement.
The Walker MAFS did not do as well on another car but the factory OEM one kept the LTFT closer to zero so I used that one on that car.

I do have a box of used MAFS for all sorts of Jaguars (1997 to 2005) and I write RICH or LEAN on them so I know what to expect when I swap it into a car for testing.

Some MAFS that were great readings on one car did not do as well on others (I don't know why).
Cars are 'picky' sometimes?

HO2 sensors also play a roll in the Fuel/Air ratio so don't neglect them as part of the diagnosis.

 

I don’t see whether you have an XK8 or XKR, or what year. Knowing those facts would provide us with the knowledge needed to make relevant replies.

The 8’s MAF sensor is not expensive, even for the OEM part. The R model is a different story. As far as I’ve been able to discover, the XKR MAF’s are only used on one other car, the XJR, whereas the XK8 sensor is used in many makes or cars and is relatively inexpensive. If I have this wrong, I’d love to hear from those more knowledgeable.

Z

 

How very stupid of me not to list accurately thr car type.

2003 XKR 4.2L Supercharged British model (RH drive)

 

i don’t know if the 4.2’s follow the same part delineations as the 4.0’s.


Z

 

yes it is the IAT part of the MAF / IAT assembly.

The MAF (Mass Air Flow) sensor wires are sort of concealed up inside the black plastic MAF tube. This topic has a photo of them:

https://www.jaguarforums.com/forum/x...sensor-206354/

Z

 

zray - Grateful thanks. This is most valuable info. Fantastic pictures in that thread. I had assumed that it was the 2 wires leading up to the dark glass bulb.
Therefore i guess I didn't clean the MAF sensor wires properly at all as i didn't even know they were there.
I will check this out as soon as i can in the morning. I will report my findings and results.
Regarding the question of whether the XKR 4.2 Supercharged has a specific MAF sensor I have checked quickly here in Germany and have come up always with the part number C2C7636 for the XKR. However the same part number is listed for at least the S Type also.
Same thing here on an american supplier https://www.rmeuropean.com/Products/C2C7636-MFG11.aspx

 

those same web sites have a different part number for the 4.0 XKR’s. Expensive. So it appears you are in luck price wise, and I’m still looking at nearly $300 to replace my sensor, if and when the time comes.


Z

 

Invested in the exact MAF Moly cleaner and yesterday cleaned the MAF very carefully. A short journey was fine but sadly on a slightly longer run the problem re-appeared. The P0171 and P0174 do not appear to be quite so quick to appear as initially. Furthermore, once cleared on a journey they seem not to come back. And, the yellow engine warning symbol and the 'Restricted Performance' warning come on together though sometimes the text disappears leaving only the yellow engine symbol.
So I am now pondering my options.
Replace fuel filter.
Replace MAF
Try to get a friendly workshop to do a complete leakage test with a smoke generator.
Or test the STFT (short term fuel trims) and the LTFT(short term fuel trims)
Get a dealer diagnosis done. Might that not throw up a far more precise error diagnostic?
I'm anxious not to invest too much in this car as I intend to sell on in the spring.
Frankly, i just want to identify where the problem is and fix it and not embark on an endless journey replacing one part after another until maybe eventually finding the cause of my misery.
I'll keep you posted where this goes!

 

I had the same issue. No amount of cleaning the MAF worked, replaced it with a new one.... no more problems.

 

A cheap scan tool that reads data can be used on any car to watch STFT and LTFT so investing in one is NOT just a Jaguar thing.

I try to let someone else drive while I watch the readings but you can find a deserted road and put the reader in your lap to glance at.

 

I have been using iCarsoft LR V1.0 which is I think a slight upgrade from the popular iCarsoft 930.
It claims to do everything I need for a Jaguar but I am completely unable find out where and how to check the STFT (short term fuel trims) and the LTFT(short term fuel trims) with this tool.
There is very little documentation available.
Does anybody know if this tool can show the STFT etc.?

 

Fuel trims are standard OBDII. Check if the tool has a basic OBDII "mode" besides "JLR".

FWIW, I would recommend you put more work towards the smoke test as there are so many places where air leaks can develop (think oil dipstick/cap, valve covers, EGR pipe if you have it, any of these Norma connectors, etc., etc.). Remember, a bunch of small leaks can add up to +25% fuel. Try and inject smoke through the fuel pressure sensor vacuum line, it should fill the intake and hopefully make its way in the crankcase as well.

I "made" a smoke tester with a jar, a rag dipped in mineral oil, an old soldering iron, a bicycle pump and some clear tubing. Does not have to be expensive...

Best of luck, keep us posted.

 

it does. I use the same product.

I’m presently on the road , but will post all the step
by step details tonight.

Z

 

Fantastic. I would be really most grateful for details about this. - it will be a huge help. I just cannot see this option on the scanner.
Either I am being very stupid or the device is not working correctly. I suspect the former!