Well, I hope someone can offer some insight as to what is going on... I've searched for solutions for this problem, and it's driving me mad because of its apparently intermittent and load-based problem - so here we go.

Earlier this year, I started having issues with water (from various sources, including rain run-off while parked, coolant hose mis-direction during the two episodes replacing the radiator, etc) collecting in the passenger side spark plug wells, causing me much frustration due to misfires, limp-home mode, RESTRICTED PERFORMANCE messages, et cetera.

So, in the latest episode of this repeated and maddening sequence of events, I replaced one of the coil-packs, as it had a torn boot, and one plug that broke when it was dropped after removal. From my searching, evidently this is a known problem, as evidenced by the cruddy seal the plug boots make - this was rectified by the addition of RTV around the edge... So, decent performance for a few days, then I am driving on the freeway at 65-70, with intermittent flashing MIL and RESTRICTED PERFORMANCE at throttle.... Backing off the throttle, it went away, until progressively, the MIL is on solid, RESTRICTED PERFORMANCE is set continuously, I have rapidly reducing power, and rev-limiting at 3,000 rpm.

Great thing to have going on when you're driving on I-45, right? I've also noticed that it makes this ridiculous snorkeling sort of noise on accelerating, up to the point where the rev limit kicks in - very, very, very annoying.

So, I threw it on the monitor, and it's throwing P0300, P0108, P1000, P1313, P1316, P2096 - knocking out P1000 and P0108 on that read since I caused the P0108 when I popped open the breather box, I noted that it was only throwing P0300, not any specific cylinder... When the flashing MIL/RP hit, I recorded the fuel trims as follows:

S/T bank 1 - 0.00
L/T bank 1 - 4.70

S/T bank 2 - 0.00
L/T bank 2 - 19.50

O2 sensor voltages were as follows:

bank 1 sensor 1 2.39
bank 2 sensor 1 -0.69

Intake pressure jumped from 4.0 g/sec to 11.2 g/sec as expected, so it doesn't seem restricted in air intake, so why is it running so rich? It idles fine for the most part, but any throttle causes it to snorkel/snarl badly, I can smell rich exhaust in the car, and honestly, I am about to tear my hair out over this situation... Ideas?

*** OBD data pulled when it goes into RP ***

Fuel system 1 status OL-Fault
Fuel system 2 status OL-Fault
Calculated load value 17.6 %
Engine coolant temperature 199 F
Short Term Fuel Trim - Bank 1 0.0 %
Long Term Fuel Trim - Bank 1 19.5 %
Manifold absolute pressure -8 psi(gauge)
Engine revolution speed 730.5 rpm
Vehicle speed 0 MPH
Ignition timing advance 6.5 degrees
Intake air temperature 50 F
Abs. throttle position SSR 2.7 %
Bank1-Sensor 1 present at that location ON
Bank1-Sensor 2 present at that location ON
Bank1-Sensor 3 present at that location OFF
Bank1-Sensor 4 present at that location OFF
Bank2-Sensor 1 present at that location ON
Bank2-Sensor 2 present at that location ON
Bank2-Sensor 3 present at that location OFF
Bank2-Sensor 4 present at that location OFF
Oxygen Sensor Output Voltage(B1-S2) 0.955 V
Short Term Fuel Trim(B1-S2) -4.0 %
Short Term Fuel Trim - Bank 2 0.0 %
Long Term Fuel Trim - Bank 2 13.2 %
Fuel Rail Pressure 40 psi(gauge)
Air Flow Rate from Mass Air Flow Sensor 4.72 g/s
Oxygen Sensor Output Voltage(B2-S2) 0.855 V
Short Term Fuel Trim(B2-S2) 0.0 %
Equivalence Ratio (lambda) (B1-S1) 1.000
Oxygen Sensor Current (B1-S1) 1.80 mA
Equivalence Ratio (lambda) (B2-S1) 1.000
Oxygen Sensor Current (B2-S1) -0.30 mA

*** OBD data prior to the first RP ***

Fuel system 1 status CL
Fuel system 2 status CL
Calculated load value 18.0 %
Engine coolant temperature 176 F
Short Term Fuel Trim - Bank 1 25.0 %
Long Term Fuel Trim - Bank 1 -1.6 %
Manifold absolute pressure -9 psi(gauge)
Engine revolution speed 1506.7 rpm
Vehicle speed 0 MPH
Ignition timing advance 25.0 degrees
Intake air temperature 46 F
Abs. throttle position SSR 6.6 %
Bank1-Sensor 1 present at that location ON
Bank1-Sensor 2 present at that location ON
Bank1-Sensor 3 present at that location OFF
Bank1-Sensor 4 present at that location OFF
Bank2-Sensor 1 present at that location ON
Bank2-Sensor 2 present at that location ON
Bank2-Sensor 3 present at that location OFF
Bank2-Sensor 4 present at that location OFF
Oxygen Sensor Output Voltage(B1-S2) 0.900 V
Short Term Fuel Trim(B1-S2) -4.0 %
\Short Term Fuel Trim - Bank 2 25.0 %
Long Term Fuel Trim - Bank 2 4.6 %
Fuel Rail Pressure 40 psi(gauge)
Air Flow Rate from Mass Air Flow Sensor 9.78 g/s
Oxygen Sensor Output Voltage(B2-S2) 0.110 V
Short Term Fuel Trim(B2-S2) 0.0 %
Equivalence Ratio (lambda) (B1-S1) 1.250
Oxygen Sensor Current (B1-S1) 1.56 mA
Equivalence Ratio (lambda) (B2-S1) 1.250
Oxygen Sensor Current (B2-S1) -0.69 mA




** NB: It only throws P0300 and P1313 in RP, along with P1000 ... Totally confused.. No water in previously suspect plug wells (1, 3, 5) but it did at one point throw misfire in cyl 1,3,5 but that was probably when I was unplugging cylinder 5.... Curiously the engine didnt change idle or shudder any worse or better when I unplugged the coil pack for cylinder 5 - indicative of yet another failed coilpack?


ARGH.

 

Whoa, hold on a minute! How do you expect any help after providing such detailed troubleshooting? We aren't used to that. Please reformat your query using the following template, to which we are all accustomed:

"So I was driving my car (do NOT specify year, engine, etc.) and this (do NOT specify) light comes on and I got a (do NOT specify) message, too. I took it to (insert name of cutrate auto parts chain with a code reader, not a scanner) and they said I had a (insert vague nomenclature but do NOT under any circumstances include the actual DTC) fault. I reset it (do NOT specify how) and the light and message came back (do NOT specify when). My cousin's roommate told me it's probably the (insert name of obscure, expensive part)."

All seriousness aside, that's some great info you've provided. We've got a few members who a brilliant at interpreting fuel trims, etc. Hopefully one of them will chime in soon. In the meantime, here's some good reading on the subject:

http://www.jagrepair.com/UsingFuelTrims.htm

 

It's taken me 10 minutes to even try to emulate that kind of response... I can comiserate though, as people I deal with in the IT industry do the same thing... I had a co-worker (middle management-level, career background in telecom sales for 25+ years) whose favorite catch-all query to confront me with was, "Is the system down?', seconded by the all-encompassing, "My Microsoft is down, did you change anything?" - a milestone in my tenure in that office was my ability to pinpoint exactly /which/ Microsoft application he was referring to solely using the intonation of his voice... Outlook, Word, Internet Explorer, Windows logon, Project.... All of which this man used daily, and had been for many years.....

 

After reading those docs, my conclusion is that I have a load-dependent vacuum leak - but still some questions...

Mainly, while I have tightened down the intake plenum fairly tight, but if this was the cause, wouldn't it cause a problem at all load ranges?

I already replaced the IMT o-rings about 20k miles ago or so, and the actuators are tightly connected... The two vacuum lines to the back of the intake plenum are secure, and disrupting them causes obvious changes, moreso than at idle currently...

The 'snorkeling' noise may be indicative of the problem perhaps, since it sounds like either the cats are plugged and it's getting backpressure at higher throttle, but at idle and minimum throttle, it seems to be okay - it only does the RP/MIL dance when I start to load the throttle....

I'm really not in a position to chuck out the several hundred dollars it will take to replace all six coil packs, put a new set of Iridium or Platinum plugs in it, replace the fuel filter, fuel injector o-rings and fuel injectors, et cetera right now. In fact, this car has unfortunately spent extended periods of time parked at a friend's house in frustration and aggravation... Ugh.

 

This may help with the vacuum lines:

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

 

Rick, that post and diagrams got me through the first six months of owning this car... I wish it were that easy at this point now - those are all tight and solidly connected :/

Could not be a vacuum leak then, if it's not any of those; what I /really/ need would be a better map of where the coolant hoses to the throttle body go...

top - ?
bottom left - ?
bottom right - ?

Maybe coolant flowing the wrong direction causes a manifold pressure drop or increase under throttle that's sufficient to trigger this? If so, then why would it be okay for a day or two? :/

Clues, clues. Bah.

 

Pictures attached. Don't know why I can't attach the CSV via filedropper. Argh.

Ideas?

 

Why did you have P1000? Should have been P1111.

When and what work was done recently, if any? Might hint where to look.

Fuel economy will be bad due to OL (in this case OL-Fault). It dare not run lean so tries hard to run rich. Not good for the cats but lean is an engine-destroyer.

STFT 25% suggests it was desperately trying to learn (re-learn?) how to fuel, seeing too much air.

Can't say whether an air leak as lots of data but nothing to show that. Hot engine, at idle and again at about 2500rpm. Normally people do not have P1000 nor any really odd things so LTFTs are all that's needed but I suggest you do STFTs as well.

If all is OK parked like this let us know - then you're probably looking for what kicks in (EGR, EVAP, whatever) but not as it should. Or maybe a bad cat... IR gun to check temp / peer in O2 sensor hole with borescope.

I doubt it's due to spark plugs unless they're the wrong ones or way over age. Coil(s), could be.

Avoid that flashing MIL!

 

My Theory du Jour(tm), offered for free, and worth every penny:

Your engine has a load dependent problem, but I'm leaning towards an ignition issue, not necessarily a vacuum leak. Keep in mind a vacuum leak sucks in more (unmetered) air at idle, when the pressure differential is highest. At wide open throttle, it's just the opposite. I'm still learning about interpreting fuel trims so I may be out in left field, but bear with me.

You currently have codes for misfires on cylinders 1, 3, and 5. What do those cylinders have in common? The spark plugs sit in a common well. If oil leaks from the valve cover gasket and fills the well, it will short out all three cylinders at once. In my not-so-humble opinion, that is the most likely fault to affect 3 cylinders in one bank. I know there could be an issue with the wiring harness, or camshaft timing, etc. However, I once found oil collected there on my car and it caused a misfire, so therefore EVERY similar problem MUST have the same root cause. Life is much simpler that way...

Now please allow me to save you the trouble of replying to ask how such a fault can be load dependent. Very simple: The voltage requirement of a spark plug is load dependent. The main variable is cylinder pressure. Making up some numbers from thin air, at idle with low cylinder pressure, a plug might require 10,000 volts to fire. Floor the throttle, which causes a big jump in cylinder pressure, and that same plug might require 20,000 volts to fire.

No matter the throttle setting and resultant cylinder pressure, each coil only builds up enough voltage to fire for the current conditions. Once the voltage level reaches a point that the plug will fire, the voltage level stops rising. As long as a coil can supply in excess of the maximum a plug will need, it will always fire, regardless of how much voltage is actually needed and supplied.

The problem is when a coil's output is degraded. Using the same numbers I made up, let's say a coil can only put out 18,000 volts. At idle, if only 10,000 volts is needed, all is groovy. Part throttle, let's say you need 15,000 volts, but we're still good. Floor it though, needing 20,000 volts, you've got a shortfall if you can only supply 18,000.

Back in the days of points ignition, this math was more critical. As long as the ignition system could supply more voltage than was required, all was good. As the points would wear, the available output would decrease. Eventually you'd reach that equilibrium point and misfires would occur. That's why we used to have to pull ignition system maintenance every few thousand miles. Modern electronic systems have almost eliminated that gradual drop, but other factors still apply to decrease the output. Oil on a plug boot is one of those factors.

Spark plug wear is another factor that changes the equation. As the electrodes wear, the gap increases and the corners erode. A bigger gap requires higher voltage. Same with rounded corners, as a spark can jump more easily to a sharp edge.

Dag nab it, you got me going on my ignition theory. Hope I didn't bore you. As lousy as access is to bank 1, look for oil in the spark plug wells. If you do find oil, you'll need a new valve cover gasket. And change those plugs while you're in there, as mentioned in the previous paragraph.

That's my story and I'm sticking to it. Lots of problems are much simpler than we tend to imagine.

 

With LTFT on bank 1 high and a gas smell, the problem is obvious a misfire. Replace spark plugs and coils on the cylinders that you already know have a problem. Since water got to the plugs, you could also have a shorted out computer. That happened on my F250. Confusing as hell to diagnose that until I realized the computer is shot. It was actually the fuel injectors AND spark plugs that were shot with that vehicle.

 

You have codes. Clear them and check what comes back and focus on those. You have mis-fires.

No. Water in your spark plugs has nothing to do with water getting in the PCM. All the spark plugs can short out without affecting the PCM.

It is vary rare but has happened that the PCM DID get wet. But lets stick to your codes for now. We know those are a problem. A wet PCM is a long shot for now.
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