Hi everyone,
I'm a 2003 3.0 v6 x type owner. After reading many threads on this topic and trying many fixes I decided to pop up a thread my self to see if I could get some tailored help by the more expert guys on here.
here are the work that's been done on this car:
-both upstream lambdas failed in last 10k miles both have been replaced with Densos
-pcv hose, break booster pipe, imt o rings, and upper manifold gaskets replaced as I had typical issues with splits and hissin manifold.
-Maf sensor replaced with Denso as I was getting codes for that as well now codes are gone.
-throttle body ribbed intake hose clips replaced.
-spark plugs replaced with platinum ngk's

Bottom Of the post you should be able to see my fuel trims.


And unrelated to this problem: thermostat topo hoses, coolant hoses, and reservoir all changed, battery upgraded, new AC compressor , new service belt and pulleys.
i've owned this car for less than 5k miles... I love her when she's working well.. but the issue has been one after the other.. lol

please help!!!

 

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let my try again


they show on my screen I hipe they dont go casper on me as I hit the submit button
😂

 

ProFiler, do you smoke? If so, get yourself a nice cigar and light it up. You want to do this when the engine is cold and you have some good light. What you are going to do is take a good puff with the engine running and gently blow the smoke into your engine bay. watch the smoke as it wanders through the engine bay. It should just wander through in a fairly straight line till it runs into something. If you see the smoke make a sudden direction change, that is pointing to where your vacuum leak is. If by chance you don't smoke, then I am sure if you buy a nice cigar, one of your friends will smoke it for you.

Based on the work that you have done, I can think of 3 more potentials that you have to deal with. the most difficult is the lower intake o-rings. If you are going to have an issue, it will most likely be here. Fairly cheap to get (about $25 at a local autoparts store (ask them for the lower intake gaskets for an 03 Lincoln LS 3.0L, they won't have them if you tell them your car). The next spot I would look is on the back of the intake. There is a single vacuum line there that will need to be checked. Finally, if I am remembering the X-Type correctly, if you look under the throttlebody, you will see a green tube and an orange tube. See if these have developed cracks in them.

The other trick you can try (if the engine is already warm) is to get yourself some flexible tubing (about 4 feet long). You want to put one end near your ear (not in it due to potential ear drum damage) and then you are going to run the other end around every point you can find that would be a potential vacuum leak area. When you get near the vacuum leak, you will hear the sucking sound in the tube. Just be careful to not get the tube too far into your ear so you don't damage your ear drum by creating a low pressure near your ear (think what happens on an airplane but many times worse). The other thing to pay attention to is to not get the other end too close to rotating equipment.

 

Hi thermo,
thanks for the input,
So this morning I had the car smoke tested no smoke came out except from the airbox.. so we concluded it couldn't have been a vacuum leak.. we came up with the idea that it could have been a coil pack misfiring and others compensating.. so I changed em all myself cause .. why not. Haha While I was at it I changed the lower manifold gaskets is that the ones your referring to when you mentioned lower o rings? I then rebuilt everything and switched it on .. very rough idling.. I remembered there was a vacuum line at the back and snapped it back on. The idling went smooth again.. the cruise not available message went away and so did the rev limiter.. the kitty was purring again! Cleared the engine management light and started reading live data.. everything was lowered to decent standards. Not perfect but within the ten% allowed.. took her for a spin .. kicked my foot on the accelerator and noticed a bit of hesitation .. only the slightest ... parked up went to read data again and I was once more in the high 20s and low 30s for fuel trim 3 and 4 respectively again ...im sure the light will come back on again in a few hours... I'm Lost!!!!

 

I'm assuming you posted the code incorrectly (p0174 = lean bank 2)?

If so, and you've done all the other above suggestions, it can be caused by a bad O2 sensor. It will be the bank 2 UPSTREAM one. Near the radiator battery with the Gray wire.

https://www.jaguarforums.com/forum/x...-p0174-128891/

 

Hi Dell,
my bad yes that's the code lol
the sensor you mention was changed less than 5k miles ago. Bank 2 upstream was bad when I bought the car and I was aware at purchase.. changed it everything went well till recently when the other failed... and I got these codes for maf and bank 1 upstream those have been replaced and those codes have gone away..

any suggestions as my system still show lean in bank two?

 

Dang, next one is IMT but you say you replaced them. The last thing other than the O2 is a MAF sensor.

I've read on other models the air intake sensor itself being bad but have not read of an X ever going south. On ours it's always been just the seals.

 

One last long shot. Is there any small split, hole, connection gap, etc. on the ribbed (accordion) intake hose or misfit of the airbox (filter part)?

 

yeah , The clips were kinda loose so I bought new ones sturdier ones from halfords the type you screw into with a philips to tighten.. no slide no movement once tightened .. I'm lost .. really really lost ... 🙈🙈🙈
btw I drove this evening.. engine light back on.. no cruise light on .. rev limiter back ....

 

No evident splits, the clips were a bit aged so I replaced em with adjustable ones and got em on there proper tight.
I heard sometimes a blocked injector can do these kind of tricks on the car .. or a bad fuel pump and or pump sensor/valve.. gonna check that hose again ... thoroughly and keep moving in order of elimination ..

at least she's getting that overdue tlc of components hahahaha !

 

XTyperProFiler: A lean condition P0174 is caused by too much air OR too little fuel. Too much air is more common because air can leak in numerous ways. You've checked and rule out the common vacuum leaks, and a few uncommon ones as well.

Suggestion: Stop searching for vacuum leaks and start looking for why there may be insufficient fuel to one or more Bank 2 cylinders.

~67 PSI fuel rail pressure is more than adequate, and if the fuel pressure was too low, you'd have lean conditions in both banks, not just Bank 2.

So what could cause a lean condition in Bank 2 but not Bank 1? One possibility is a dirty fuel injector in cylinder(s) 2, 4 and / or 6?

Try a healthy dose of fuel injector additive. If that doesn't work, remove the fuel injectors and for a modest fee have an independent mechanic clean and test them for consistent flow rates.

www.mrinjector.us does this by mail for $17.50 per injector plus postage. His video shows how dirty injectors can cause a lean condition in some cylinders, while the other cylinders receive adequate fuel:

You Tube

 

Thanks DW 🙂,
Winns extreme fuel additive has ben added to a full tank, now we wait and we will see, also grabbed a fuel filter for a tenner gonna slap that on at some point today.. And if this doesn't do it then yeah next option will have to be fuel injectors get em all checked.(especially n.6)
I agree about fuel pump and fuel rail pressure I just thought that maybe .. just maybe its the last cylinder n. 6 struggling to receive fuel due to being the last on the rail coming from the pump . And a low fuel pressure could feed the others just enough up to n. 5 but not enough at 6 .. hence my idea .. especially as I'm running out of those lately 😂...

thanks for your input I'm definitely taking that on board.

thanks to everyone so far for taking the time

 

I didn't really pay attention to the fuel p.s.i. But, normal is 54-56. Yours seems pretty high. Idk what would cause that pressure increase (20% higher than norms).

 

hey bud, I changed the fuel filter today and that dropped right down too 55.6% the psi corrected itself.. also all the fuel trims where correcting themselves in the short term trims and the cruise light went off.. I cleared codes and went for a spin with live data on and noticed everything going back to normal then once the car was properly heated they started surging again and all the lights came back on.

I'm now pretty sure since air is fine, spark is fine.. and fuel pump.. pressure and filter are fine that the only thing can be ... as you said a clogged up injector in need of servicing I found someone locally and ill be calling them first thing tomorrow morning.

also to note that both o2 sensors were tracing good levels of oxygen going into combustion (upstream) and loads coming out of bank 2 after combustion (downstream) and into cats making your suggestion even more plausible.
thanks for putting that thought into my mind it rearranged my whole way of looking at my data !! I may owe you a few beers if I ever run into you

cheers!!

 

XTyperProFiler: If I understand correctly, your engine runs well when cold, but stumbles when hot and throws a P0174 lean code for Bank 2.

Assuming this is correct, and since you've ruled out the likely vacuum leaks, the symptoms you describe are consistent with a clogged injector(s) on cylinders 2, 4 and / or 6.

When the engine is cold, the injectors stay open a little longer to spray additional fuel, because cold engines prefer a rich fuel to air ratio. This is analogous to choking a cold, carbureted engine to increase the fuel to air ratio until the engine warms up.

Here's a theory that could explain your engine's odd behavior...…

When the engine is cold, the injectors stay open longer to add extra fuel. But because the Bank 2 injector(s) are dirty and restricted, instead of the preferred rich condition, you get a fuel to air ratio that is normal, so the engine runs relatively smoothly.

But when the engine is hot, the extra fuel ceases, the dirty fuel injectors in Bank 2 cause the fuel to air ratio to be too lean, so the engine runs rough and throws a P0174 lean code.

It's just a theory. To confirm, see if the fuel injector additive works, or have the injectors serviced by a mechanic who measures the flow rates before and after cleaning. If you go this second route, number the injectors as you remove them so you'll know if cylinders 2, 4 and / or 6 had the most restricted injectors prior to cleaning, as suspected.

 

What you're saying makes a lot of sense actually, my fuel trim numbers are quite low on bank one , they are rich (-5% to - 1%) when car is cold and low positive once hot (+1% to +5%) but my bank two is (-14% to -25%) when cold and (+25%) when hot. Does this support your theory about the injectors? If so is it doing short trim adjustment to counter the long term recorded from previous runs?
​​​​​​also if I remove the fuel rail and injectors are there gonna be some seals or clips that are gonna need replacing ? Sorry for the thousand questions hahahaha

 

hi again
so I personally replaced all the fuel injectors, and no change once in closed loop fuel trims skyrocket to +25-30 % even when I'm off the pedal.
​​​​​​fuel rail pressure is 55psi goes up to 60psi when hard accelerating and drops to 46 in between high revs, so I concluded fuel pump is working well.

worth mentioning that all my sensors part from bank 1 sensor 1are showing good voltage and amp
my bank 1 sensor 1 is showing a negative voltage -0.1 or something of the sort.
this sensor was recently changed as I had a code for it.

could this be a reason for everything? Allthough it's on the opposite bank from which am getting the lean codes and fuel trims?
at this point I will check all fuses and look into electrical issues.. or possibly ECU flashing.. clueless ..

 

So long as you used the proper kind of sensor(s), the upstreams measure current so voltage can be rather misleading!

Does your big trim drop a lot when revving (parked, hot engine)? If so, you're looking for an air leak.

 

thanks jag v8 yes it does, also my MAP IS STEADY 9-10 mHg at idle. Its pointing me back to a leak, but just for confirmation, if my Manifold pressure is low should I focus on looking for a leak in the manifold?I've smoke tested it twice and nothing ..

 

Hi again everyone, still trying to tackle this issue,
Hope someone can give a little insight.
so I've Been watching my fuel trims on different drives, and noticed a trend, no matter what the ltft are the car is always able to compensate with a rich command while in idle or low revs, the minute I rev to fast especially under load/uphill .. The stft sky rocket straight to 25% and sticks there no matter what speed or rpm for the rest of the journey dragging the ltft up along with it,
The only way to make it "unstick" is to get in neutral and snap the throttle a few times it it then goes to 0% on stft until I put it in gear and it goes back to correcting the high ltft.
The other way is to start the car again it all goes back to normal with high ltft and equally negative stft. Both these methods allow the car to compensate Until the ltft goes down gradually back to 4 or 5% lean with 3 or 4% rich commands on stft.

What's happening here? I can't make any sense of this