Hard reset means you zeroed the trims.

So, it has to relearn.

You also zeroed its knowledge of how the various devices behave (*), so again it has to relearn.

(*) in your case, especially the injectors - yes it needs to know how much fuel each one delivers for what length of pulse.

You could help it by following the drive cycle (in JTIS / codes PDF) but that's not essential.

Those codes do NOT have to mean you have an air (vacuum) leak - as has been posted endlessly and as JTIS makes clear.

Let the relearning happen (either varied driving or the drive cycle), then check the fuel trims to see whether you have an air leak (and on one or both banks). There are many posts saying what to do so please read them. It's a lot easier and much cheaper than what you've been through.

Do NOT clear any codes or you set back this process. Also, do not do another hard reset unless you want to go back to the start of the entire learning process.

It's OK to use OBD to read data (such as each OBD monitor status, sensors and trims).

To a fair extent you can see it's done relearning if the STFTs are (roughly) symmetrical (about zero) - which means it has adjusted the LTFTs. (The whole point being that STFTs migrate into LTFTs to compensate for minor engine device issues and once stable the STFTs are to provide instantaneous control based on solid LTFTs. If needs be, read about how cars have worked for the last 20-30 years.)

If you can (safely!), do some "coast downs" i.e. get up to about 60mph (50 is probably OK) and let the car coast to as slow as you can - but do not upset other drivers or take risks. (It uses these to understand exactly how the crankshaft behaves so it can detect misfires.)

As I expect you know, some monitors have conditions under which they will not run. EVAP is one. Because of fuel vapours the tank can't be too empty or too full.

And so on. It's why the documentation exists

When working it's how the car is smooth and powerful with good MPG. It's why they start well, drive well, and don't cut out like cars used to do.

 

Thank you for your feedback . Yes, I will try to be patient and let it relearn. I will heed your advice elsewise as well. Yesterday when I did the hard reset, the car resumed smooth idle but the fuel trims remained as before the surgery. What I have been experiencing is ltft's that sit at 19.5 at idle and immediately drop to 0 upon increased throttle, with stft's being near 0 but increasing with throttle. I have been studying this on this and other forums for years, and post after post says that is a classic vacuum leak or insufficient fuel. Since I had a professional smoke test the car with no leaks detected and replaced all the air related components I could think of, and because injector cleaner seemed to have some effect on the issue, I landed on injectors as the problem. But....I am aware that there could still be an issue that is the root cause, meaning nothing would surprise me at this point.
I was encouraged yesterday to see that after 3 separate random starts and drives, the fuel trims changed dramatically. To my surprise, the ltft's dropped to 0 and remained there at freeway speed AND at idle, while the stft's also dropped to near 0, but fluctuated instantaneously with throttle demand.
I've kind of reached the point of simply wishing the problem goes away , and I will keep my fingers crossed that todays 70 mile commute to work and back will result in good numbers with no codes or cel.
I do thank you for your kindly advice, and I request that all of you guys keep watching this thread for updates and giving me support.

 

To recap, throwing parts at the P0171 and P0174 codes that are troubling you. This is a collective list that I am writing from 9 years of reading this forum 3+ times daily if not more. I am going to take it that you have read the "In an effort to" color coded thread I did years ago, located in the "How To's". If not start here:

https://www.jaguarforums.com/forum/s...ics-faq-52720/

1) You stated you replaced air filter. Is it an OEM or an oil type brand like K&N?
- our vehicles MAF's do not like to play well with "oiled type filters" nor aftermarkets

2) Are you positive the lid on the airbox lid is fitted correctly
- you must remove the airbox or at the least lift the entire airbox to properly fit the
lid, do not fool yourself

3) New MAF
- our vehicles like OEM's and do not play nice with aftermarkets

4) There are issues with the plastic intake tube cracking underneath making it difficult to
diagnose. Though this is recorded here more with the preface vehicles our '05 MY's are
getting to that age.

5) The '05 MY's only have 5 vacuum lines. You said you replaced them all? Just out of
general maintenance, I replaced all of ours a few years back for under $200.00

6) Plenum off, did you replace the (6) plenum seals and the (6) lower intake seals?
-Were any of the brass threads loose or pulled out when you removed plenum?

7) While replacing sparkplugs and coils(?). Did you notice an oil on sparkplugs or coils?
-This would indicate that the valve cover gaskets (seals) and sparkwell bosses have
failed. *This would indicate more of a misfire condition (ex. P030?)

8) While we are on coils (COPS), it's been noted that aftermarkets don't play well either
with our motors. I even installed a brand new one in a forum members 3.0 years ago
which I believe came cracked, I had to replace under the plenum after I had it all
back together. This would also indicate a misfire P03?

9) Purge control canister
-See above link provided, again difficult to diagnose.

10) IMT orings,
- Replaced with updated green, installed correctly and did you drain the 1/4 cup of oil
or so out of the lower chamber?

I will guarantee you your P0171 and P0174 issue lies within the above questions, just a matter of finding out which . At least in the years I have been here that is the break down. Check, check again and recheck, you are close to resolving and still way ahead of the game by DIYing!

 

I would continue with the reset procedure and if does not show resolve then I would attempt to identify a leak.

When I was looking for a leak on my xk8 I did a smoke test but we had to increase the pressure/flow on the smoke machine the find the leak and we had to use a flashlight to see the escaping smoke better. It revealed a crack in the intake manifold.

Looking at P0171 & P0174 they are giving several causes and I am sure you have checked them all but I wanted to list them to be sure.

Engine misfire
Air intake leak
Fuel filter / system restriction
Fuel injector restriction * Replaced
IP sensor fault (low fuel pressure)
Low fuel pump output
HO2 Sensors
EFT sensor fault (low fuel temperature)
MAF sensor fault
Exhaust leak
ECM receiving incorrect signal from ECT, MAF, IAT, IP, EFT and TP sensors

I listed them so you could check off what you have checked or replaced.
At this point I would focus on the EFT sensor after your reset procedure and the smoke test since you have checked everything listed above. If I recall we had two other situation relating to the EFT but I do not recall the exact situation directing us to it.

Additional Information

Link JagRepair.com - Jaguar Repair Information Resource

 

Sorry Rick I did not see your post.

 

As LTFTs drop a lot on revving it pretty much has to be an air leak.

(Coil giving misfire often gives a P030x code where x is the cyl.)

 

No worries Gus. You touched on a couple more causes. With a bit of patience, jakesdad check off as you said.

Along with JagV8 I believe the trims are pointing to a vacuum (air) leak.

 

Thanks to all of you for the extensive checklists and suggestions. Responding as honestly as possible, I can't remember which specific mafs or filter I used. Coils were intermotor u435 I believe. I did replace the imt rings with factory oems. I did not replace the lower intake gaskets. I did not replace any vacuum lines. I examined them all and they looked in really good shape.

Strange fuel trims last night that were really encouraging. I was getting both stft and ltft near 0 on both banks at speed and at idle, and that has never happened. However, when I started the car cold this morning, the ltft's (starting with bank 2) started to climb at idle to 19.5 ( I believe they won't go higher than that). This was a setback for me because it was a reversal of last night's readings.

What about my fuel pressure reading of 55psi? Is that normal?

I have no choice but to continue to fight thru this, so I will ask for your continued support. Thankyou

 

I know what I would do at this point if the vehicle in question were my 13 year old, 200k S Type. I sure would not take it to a dealer for a $120.00 diagnostic fee but use that $120 towards a couple new parts and enjoy a trouble free/peace of mind vehicle for at least another couple years.

Yes, I would refer back to post #23. But that is just me.

 

Thank you for your persistent coaching and coaxing. I won't give up. And I wont take it to a dealer or other professional. They are just guessing like me but charging me for it. Can I ask again, what should fuel pressure be on this car? Mine is reading 55psi on the obd reader. Is that high or low or?
This car was one of those effected with recall for bad gas tank seals in 2007 and it did supposedly receive a new tank at the dealer at that time. However as I have said before, the car has a gassy smell if I top it off and I have not yet lifted out rear seat to check the tank seals for evidence of leak. If it was leaking, could that be the sole reason for 0171 and 0174?

 

I've been following this thread with interest. No specific advice to offer, only general: OBD II effing rocks!

I was drawn kicking and screaming into this modern world, but once I realized resistance was futile, I've slowly come to love the diagnostic capabilities. Not only that, the performance and reliability of any OBD II car for me has been phenomenal.

Working on these newer cars requires a different mindset. No whining about how easy it was to work on non-computerized vehicles. Case in point: I've got an '84 F250 pickup that recently started running a little rough. That was the last year before fuel injection. It's got an old-fashioned carburetor. It's got a distributor. It's got a handful of sensors that independently control various other things. But alas, it's got no central computer to control and monitor everything. So say, for example, the carb has a partially clogged jet that reduces power and affects the manifold vacuum. Meanwhile, the distributor incorrectly adjusts the ignition timing based on the improper vacuum signal and the original fault snowballs. Too many individual systems are operating more or less independently, with nothing to keep track of the big picture.

Now compare that to an OBD II vehicle like our S-types. Got a clogged injector? That cylinder will have reduced power and trip the misfire monitor. With almost any fault, the computer is smart enough to know what it should be seeing under any scenario. In fact, if a sensor appears way out of limits, the computer is smart enough to ignore it, substitute stored values, and then tell you about it.

Sounds like you've already got a scanner. Don't curse at the poor thing. Make it your friend, and let it tell you your engine's secrets. I am in awe of mine, how it lets me see live data and records faults. There's no going back. Walk towards the light... Walk towards the light...

One last thing to keep in mind. Computers are really, really smart while simultaneously being really, really dumb. They can only see and do what they've been programmed to see and do. They can miss some really obvious things if not programmed to catch them. For example, if your engine threw a rod through the side of the block, the computer can only notice the lack of power output from that cylinder and flag a misfire. There's no "thrown rod" sensor.

Same with your vacuum leak codes. There's no "vacuum leak" sensor. It's more that the computer observes multiple sensors, some out of range, and extrapolates there must be a vacuum leak causing this particular set of readings.

Just remember it's a different mindset to understand modern cars. The more I work on advanced vehicles, the more I like them. And I'm just using a basic scanner and some other ordinary diagnostic tools. There are some sharp gurus in this forum. Follow their advice, cross over to the light side, and you'll find that fault.

 

The tiniest of leaks - ones you can't see - will screw up the trims.

 

55psi sounds OK.

The tank is meant to be sealed so that EVAP etc work.

Again, I keep saying the tiniest of air leaks can screw up fuel trims.

 

Bravo Bravo!!!




Ok OP,

I do not know the values that you are inquiring about. I may in the near future hook up to Joyces Jag and check where ours are at. The vehicle is not home presently.

With all the veteran members posting within this thread, you have well over 40+ years of combined knowledge working with you to resolve your issue(s) on a 13 year old vehicle with 200k on the clock. Karl's post #31 is so spot on! Embrace what your OBD II and your "friends" here are trying to tell you. You have an air leak! Very common to these V6's, both preface and post.

I am going to say this one more time before I become a reader of this thread as I have offered everything I know and I do not like sounding like a broken record.

Your vehicle is 13 years old, 200k. It is very well documented on this board and all the other JF modern vehicle boards, the plastics chosen to be used are inferior, they crack (sometimes hairline) shrink and become very brittle. Your vehicle is old (no offense mine too). Lots of heat cycles throughout the years which, refer to last sentence.

For well under $400.00 (just a number I pulled out of thin air, I am sure it will be much, much less). I would contact forum sponsor SNG Barratt have VIN in hand, order all 5 vacuum lines. I would then purchase aftermarket FelPro gaskets for valve covers, which come with the sparkplug bosses and bolt gussets. Also FelPro lower intake and Plenum gaskets. Make sure you have green IMT o-rings.

I would then arm myself with JTIS or a purchase a subscription to alldatadiy.com (back 9 years ago I had a 5 year subscription before JTIS was offered on the net). Stock the fridge with cold bevies, and dig in replacing everything mentioned. I know I am being a hypocrite by throwing parts at the vehicle but, everything mentioned is a probable cause to the P0171 & P0174 AND will fail sooner rather than the later. I personally replaced everything I have mentioned at 45k (9 years ago) on our S Type including the sparkplugs (in the day over $10.00 ea.). Why, you may ask because I was already in there, I had read everything I could on this forum and lastly, it was relatively inexpensive except for the plugs. Joyces Jag has not had as much as a hick up since!

I mentioned valve cover gaskets a couple of times throughout this thread. They are inexpensive, they WILL leak and add about 45 minutes to replacing the plenum/lower intake gasket job while the plenum is removed.

I will try to get the LTFT values for you as mentioned. I do not believe the "gassy" smell from the gas tank has any affiliation to the codes you posted. It would take you less than five minutes from start to finish to check the seals. Simply release the 2 catch hooks one each side of the front rear cushion ,lift up, push seat belt buckles through cushion, remove black covers, no tools needed. As I type this, are you sure the "gassy" smell is not coming from your engine compartment since your engine is not running correctly, kinda makes sense to me.

Good luck, I will sit on the couch now.

 

I want to say thanks to all of you for the continued feedback and advice. I think there is some misperception (just a bit) that I am not embracing the contributions of the forum or the technology of the obd. I just want to remind everyone trying to help me that I have been a member of the forum for years and self maintaining this car for a very long time with the help of all of you. I truly appreciate the sentiments of just replacing a whole bunch of components all at once on this old car, and I wish I could do that, but I guess I have to come out and say that I am a retiree on a very limited fixed income and I do not have the ability to just bite down and order a bunch of parts. If I could, I would trade in the car and buy a newer one with a small car payment but can't. So...what I have to do (with your continued patience and support) is figure out one item at a time, which is the culprit. The gassy smell occurs only if I fill the tank more than 3/4 full and seems to dissipate as volume decreases, so as dumb as it sounds I have not yet pulled the rear seat to look, but I intend to in the coming days. I sort of shelved that one since the tank was replaced with the recall and I don't want to believe it is leaking. There is no fuel on the ground. Yes, I do believe it is a vacuum leak per the fuel trims and multitudes of posts I have read about it, but please understand that I trusted a professional mechanic to smoke the engine as I watched and this experienced technician could not find any smoke escaping, nor could I as he performed the test. I then replaced the mafs (twice)..no change, the fuel filter..no change, the air filter..no change, gas cap several times..no change, 02 sensor on bank 2..no change, all spark plugs and coils...no change, imt rings (green)...no change.. During the recent injector change, I got up close and really looked at that brake booster line and it looks like new all around and snugly attaches to fitting. I looked at the little red line that inserts into the fuel pressure regulator boot on the back of plenum and it looks good and is snug in the boot.
Things I have not changed yet.....anything related to evap (there is a contraption just above driver side front wheel well with a quick disconnect hose to throttle body) that I think some others have indicated as a potential evap leak. a little black canister. What is that device? btw...evap monitor NEVER completes.
I have not changed fuel pressure regulator. There is a crankcase line from passenger side valve cover that goes into the air intake just before the throttle body that just slides into the air intake about an inch. I don't see how it firmly attaches in there or if it is supposed to be a hard attach. I think it is possible that this could be the source of a leak between the filter and the throttle body, but it would be a very small leak if so. I would like more feedback about that line and attachment.
And shame on me, I did not replace the lower intake gaskets ( I did the uppers), BECAUSE....I was literally sweating bullets about getting the injectors out and car back together at all, and i did not want to further tear it down. Due to heat and age, all of the connectors and wiring are really tender in there..and the wiring is TIGHT! It was hell just getting each harness off of injectors and back on because there is no wiggle room in there whatsoever.
With your help, I would like to proceed with the next logical possible source of problem until everything is ruled out except the lower gaskets and then do what I gotta do.
Please don't give up on this old man.

 

Yeah, definitely look under the back seat. Sounds like you've already nailed down when the smell/potential leak occurs.

Another aspect of successful troubleshooting is to fix the known faults before looking elsewhere. Could the evap system be drawing in extra air through the same leak and causing your lean codes? I don't think so, but who knows. I'd have to look at how the evap system is plumbed. But as lazy as I am, I'd first fix what certainly appears to be a leak and go from there.



Something else to keep in mind: Most tests have some limitations, and that is not always obvious. The smoke test puts positive pressure in the vacuum lines. In operation, the lines are under a vacuum.

Two possibilities here:

1) If there are any check valves in the system, that will keep some lines from being pressurized during the smoke check. You'd have to carefully look through a diagram of how the lines are plumbed.

2) Sometimes a rubber line can split in such a way that it only draws air in (a vacuum leak), but seals shut under pressure of the smoke check.

To get around both of these limitations, try spraying carb cleaner around any vacuum lines with the engine running at idle. Watch the short term fuel trims. If the carb cleaner gets sucked into a vacuum leak, the fuel trim will change. You may also hear the idle speed react, but often the computer responds quickly enough to maintain a steady speed, so watching the fuel trims is important.

 

I am not giving up on you. I understand about retirement and how difficult it can be. I am sorry if I made you divulge more about your personal life than you wished too, again my apologies. I assure you that was never my intention.


Karl gave you a good idea about spraying carb cleaner (also noted in post #23 within the link provided) in and around all the vacuum lines while vehicle is running, 9 out of 10 times this seems to work. I will tell you that there are instances here on the S Type board that carb cleaner did not work and the problem turned out to be a cracked or split vacuum tube. Some DIY'ers have tried propane as well with about the same numbers. As Karl mentioned above, the OBDII will guide to what is wrong, the problem is the OBDII capabilities is unable to tell you "purge canister cracked" or "brake line booster not seated correctly in rear plenum" etc.


I see a couple other veteran members lurking on this thread which adds another 20+ years of combined knowledge. I simply stated what has been done to correct the P0171 and P0174 problems from other members that I have read about over the years. I am going to take a backseat and may be they will chime in. I cannot offer any more of my knowledge, so therefore I will sit back and hope for a speedy/cost effective resolution for you. I posted the link to the following pictures in post #23. I hope it makes it easier for you to identify and spray carb cleaner around the vacuum lines. Start with the camshaft vent tube that you questioned that goes into the intake tube.


One last question though. Since your ownership has this vehicle been code free or did you purchase it with these problems? All the super tight wires mentioned makes me wonder.


Enjoy the pics:

 

Thank you for all of the help so far, and these are great pics. I definitely will try the carb cleaner spray around the possible leak points. Yes, I did use green imt rings. I have not yet replaced the evap purge canister and I think I will order that one next. Couple notes on mine, not sure if important. My fuel pressure regulator boot remained on the fitting, but the tiny red barbed hose slipped out of it. I just jammed it back in there and felt it sort of click over the barbs, so I called it a day. On my camshaft vent tube from valve cover to air intake, that hose (tube) basically just slides into the air intake with no clip or otherwise. It goes in about an inch but nothing holding it. Not sure if this could be a leak source.
and....I am the original owner of the vehicle, so yes, it was code free for many years.The lean codes have been giving me fits for about the last 4 years. I've just been living with it because it drives great. At registration renewal time, I have to re-smog it every other year. This year it is fighting me back.

 

Any update?

 

Hi Gus..thanks for checking in on me......I sprayed carb cleaner around all the various possible vacuum leak points and nothing happened. No change in engine sound, rpms or fuel trims.

Based on the fact that in the 2 times I have changed the maf sensor, I don't recall specifically which one I have tried, I now need to ask the members....which maf sensor is the factory oem unit for this vehicle? I will buy and replace it again. Also, I am having trouble identifying and locating for purchase, the component that joycesjag shared with me in a pic a few posts ago, labeled as "purge control valve canister" . I have read that those things can develop hairline cracks and cause lean codes, no? Can someone tell me how that part is identified and where to buy?
The car seems to running great since I did the injectors and coils, but the 0171 and 0174 pending reappear within 25 miles of driving, especially at idle speeds.
The fuel trims reflect stfts go to +25 at idle and the ltfts quickly learn from that and elevate to +19.5 soon thereafter. Both go down with throttle. Shortly after the pending 0171 and 0174 show up, the cel comes on and goes into restricted performance, which does not inhibit driving the car under 3000 rpms.


The ONLY component in this car that I have not changed that I think is related to vacuum leak are the lower intake gaskets. I'm approaching coming to grips with having to tear it down again and change them out, but I would rather try the oem maf and purge control canister first.