For the record, I never recommended that you purchase a new purge control canister. They are known to crack at the "seam" towards the middle. Very easy to remove and inspect. If it is indeed cracked, I personally would try a heavy duty type of epoxy to repair. From what I recall they are pretty expensive.

 

Did you ever investigate the possible leak at the fuel tank? Just thinking out loud that it may be connected in some distant way. The evap monitor checks the integrity of the tank's ability to contain fumes. It should be setting an evap fault code, but who knows what is happening. You had mentioned the evap monitor was not showing a completed cycle, so perhaps that inhibits displaying certain codes.

Meanwhile, the evap system keeps trying to purge fumes from what it thinks is a sealed tank, so who knows how it would react. You could try some rough troubleshooting by loosening the filler cap to deliberately induce a leak into the tank's sealing ability. See if this known fault sets a code or if it is inhibited. Won't cost anything to try.

This all ties in to my previous advice to fix any known faults first before getting too deep elsewhere.

Also, have you checked the fuel pressure with a test gauge? If the sensor is inaccurate, the pump's controller will still adjust output to the bad sensor. You could have fuel pressure out of specs, yet it will appear good on your scanner. If low, this will affect what the O2 sensors see, and the poor computer will respond as programmed and increase the injector flow rate to compensate. Eventually this increase gets flagged as a lean condition.

 

If you opt to replace your MAF sensor, go to amazon or ebay and search for a Denso 197-6030. This is the OEM MAF sensor on my 2005 S-Type 3.0 as well as on my wife's 2006 XK8. I have a spare one that I purchased almost a year ago when chasing P0171/P0174 codes on her car that turned out to be caused by failing VVT O-ring seals that are a common issue on the 4.2 engine. I tested my spare MAF sensor on both of our Jaguars for hundreds of miles each last February/March and it always functioned perfectly. You will find new Denso 197-6030 MAF sensors online ranging from $20 to $70 or so. I like having my spare because I know that sooner or later I will need it....

 

I like your suggestions. I will try removing the fuel cap and see what if any codes pop up. As for actual fuel pressure, That is also a goo idea. But I will utilize a user friendly mechanic down the street to get that reading for me. Yes, I have to pull that rear seat and see what there is to see. Thanks for reply.

 

Thank you. When the jag gets back home today, I will look to see which maf I last put in. I remember i did not go cheap on it when I ordered it from rock auto, but I also did not buy the most expensive.

 

No, you did not suggest I buy one...you merely pointed it out as a possible source, and I thank you for that. I will take a good look at it and see what I can see.

 

Lurking here. Actually, I was trying to familiarize myself with the S-type & its 6 cylinder variant. I have an '04 XK8. I did a preemptive replacement of the coolant hoses that run underneath the intake manifold a couple of years ago - what a nightmare! I never could get the fuel line to release, so did the job without removing the manifold entirely. I fought lean mixture codes for a month or two afterward (BTW, propane tests never proved of any worth to me). I seem to recall a push-in hose connection of some kind that had a plastic retainer piece that broke, and I believe it was the source of the problem. I sealed it with silicone and that was the end of the lean codes. Crude, but effective. I really enjoy tearing around in the beast (not all the time, but strategically), but I recently drove an '05 S-type while the beast was in the shop and I enjoyed the comfort and quiet, so I've been nosing around. I've been looking at the 3.0 V6 sort, thinking it would be less complex than the V8. But having read this thread, I'm seriously wondering - sounds to me like the V6 is just as demanding as the V8. The difference in gas mileage is minimal. I wonder if the overall balance of the car is substantially better with the V6. Opinions? I'm more than a little bummed to read that the manifold has to be removed to get to half the plugs on the V6 - in that regard the V8 is actually a lot easier to work on!

 

Volbrewer, we 3.0s have that same fitting located in an ackward spot on the rear of the plenum. On the 3.0s it's the vacuum line for the brake booster.

Yes, it is a very good possibility that the op has a potential air leak there. I had mentioned with pics, I believe back in post #23.

 

The brake booster line and fitting on my engine are in tact and snug. I am ruling out the brake booster line. As of this morning, I am going to settle down a bit and do a couple simple things to see what happens....I'm going to replace the maf once again, but this time with a Denso 197 6030, which I am led to believe is the factory oem...and I am going to get another new gas cap. The one on there now just doesn't seem right to me. It clicks but feels loose. I don't see how it can be creating a vapor proof seal. If anyone knows the oem gas cap, I would appreciate knowing that part i.d. as well.

 

replying to my own post...but with question for others.....re the maf sensor, another member posted that the denso 197 6030 is the factory oem part. But when I looked up this maf on napa, it says that this part is not a fit for the 05 jag 3.0. Other sites say it is. What's the real deal please.? fyi,,,,i looked at the one I put in there quite some time ago and it is a Duralast DL 3000 from autozone and according to their website, it is a direct oem replacement for that car. thoughts?

 

As I have already stated, the Denso 197-6030 MAF sensor is correct for a 2005 S-Type 3.0. I have one as a spare, and it has done hundreds of miles on both my S-Type and my wife's XK8 with absolutely no issues....

 

ok...thanks for that Jon. I will get one of those and give it a try.

 

When you were replacing the injectors did you check the breather elbow under the manifold?

 

 

Well I just found out that this car has no elbow like my car. I still think it is a small leak because it shows up on a low RPM.

 

Yes Gus....it ALWAYS shows up with low rpm. At highway speeds, the fuel trims are good. I'm about to make sure this car is leaking with a 10# sledge.

 

Thank you very much. That article you attached is fantastic. I will do some studying.

 

Question #1) Have you tried this yet to rule out the brake booster?

Also, I found some more info on the evap system. On this page, click the link at: S-Type Technical Guide > S-Type 2003 Update:


JagRepair.com - Jaguar Repair Information Resource


Or a direct link to the PDF:


http://www.jagrepair.com/images/Elec...E%20Update.pdf


Scroll down to page 62 (or page 74 of the PDF itself) to read up on the evap system.

The copy/paste function from that PDF give me all gibberish, but in a nutshell, lightly paraphrased:


"When the engine is running, air is drawn through the EVAP canister, via the vent pipe, into the engine for combustion."


Which brings me to my second question:

#2) Have you investigated that apparent #@%*ing fuel leak under the back seat?

I can't stress this strongly enough, from Troubleshooting 101:

FIX THE KNOWN FAULTS FIRST BEFORE GETTING BOGGED DOWN ELSEWHERE

Is your possible fuel leak at the tank tied to the vacuum leak? Heck if I know, but it could be and is worth investigating. You can read more about the EVAP system at the training manual linked above. One would think you'd be getting some type of fault code for the EVAP system, but it could be inhibited for some odd reason. Maybe the vacuum leak is so big, the computer is programmed to give you the P0171/P0174 codes instead in the meantime.

One suggestion is to figure out where the EVAP system is plumbed to the intake manifold. Induce a known fault by disconnecting this line and leaving it open and see if any EVAP codes are generated. Don't forget to check for pending codes, too. If no EVAP codes are given, there's probably some logic at play.

Also look at figure 47 on page 64 (page 76 of the PDF). Looks like there is a test port you can use to check the integrity of the tank, seals, and associated lines.

 

thanks KR9. Yes my car does have that test port on the evap purge canister. Not a clue how to use it but I will research. I'm gonna have to rule out a few things here...1. expose the fuel tank seals and see how they look. 2. there is a quick disconnect fitting under the throttle body that feels sloppy to me. That could perhaps be a problem. 3. After removing the upper plenum a few times now, I still have not done the lower intake gaskets, even though I do have 6 new ones on the shelf. I'm getting good at pulling off the top stuff, but I was afraid to lift that lower manifold off so I shelved it. I wonder if it is possible that the lower gaskets alone could be the root problem. And yes to all those commenting about fuel trims,,, my trims are strongly indicating air leak, I don't deny it. But as Joycesjag has reminded me more than once, there are only 5 possible vacuum leak points and if I keep convincing myself that none of those 5 are the leak, then i get sucked back in to the other posts that say any of "multitude" of things can throw 0171 and 0174.
I think it's time for me to rename the thread and start fresh.
Your assistance is greatly appreciated.