Hi Blairware,

Chevron Techron is what I use in its concentrated form to pressure-clean injectors, and I can vouch that it works (at least in its concentrated form). It's what several of our local auto dealerships use, so I use a bottle in the tank at every oil change. Like most of the commercial fuel injector cleaners, its a blend of commonly available solvents like kerosene, naptha and mineral spirits, so you could blend your own if you were so inclined. The last time I did the math the convenience of buying Techron in the long-neck bottles made it worth the extra cost.

Regarding your engine issue, I haven't thought this through, but have you had any reason to suspect your throttle position sensor? Or, is it possible that a sensor that is fundamental to fueling control is not providing an accurate signal to the ECM, such as the engine coolant temperature sensor? Do you have a scan tool that can stream Live Data to test the TPS and to see if the ECTS is reflecting a plausible full operating temperature and the other sensor inputs are plausible? How are your fuel trims?

Cheers,

Don

 

A basic explanation of the EVAP system is found on pages 76-78 of the Technical Introduction, which you can download here:

Jaguar X350 Technical Introduction

I don't know if this would explain your clicking or clacking sound, though. Purge valves typically operate on a pulsed signal just like fuel injectors - they don't just click open or closed, they open and close very rapidly while they are being operated in order to modulate the flow of fuel vapors into the engine intake depending on running conditions. We'll have to think about what is mounted in the left fender that could cause your loud click.

Cheers,

Don

 

My apologies for the long post. I just want to provide any details that might lead to someone having an aha moment!

I have been hunting down a thread I read once that references the loud click, not necessarily in the left fender, but absolutely on the left side of the engine bay. But, in fairness, it could have been in the X308 forum, as I came from an X308 VDP to the X350 - with a brief psychosis that involved a Saab 93 Convertible (don't ask.. fortunately I came to my senses) - there was suspicion of the purge valve, but if your understanding is correct, I can't see it being my noisemaker. It is almost certainly a solenoid, and a loud one at that. The events are several minutes apart, not consistent, and with no triggering event that I can pinpoint. What else could be operating loudly like this? The AC compressor is clutch-less, being a variable displacement design. What about the pressure switch? Perhaps I have a too much refrigerant or it is over pressurizing for some reason? Just a thought. I need to test with climate control OFF!

As to my idle stumble, I dont have a scanner beyond OBD2, but with that and Torque Pro, my fuel trims look pretty decent. I have experience when they are off, and have replaced upstream O2 sensor in my other X350. After about 15-16 gallons of fuel, and the larger Techron bottle, it seems to be behaving, at least over the last 25 starts. Weird that I had the identical issue on the 1st X350, but at higher mileage, starting around 150k miles. Actually both issues, the loud click/clack as well. There IS a possibly related fast idle, more of a surge up to around 1500 rpm that occasionally happens if I let it idle for a few minutes after starting. No consistency to that however.

Maybe not so weird. It tells me Jaguar built these very consistently, lol! The 1st one had one front shock that was leaking in the coldest parts of winter. Even at single digits, the air suspension in this car holds its breath all winter long. I picked this up in Ohio after driving the other one into a STOPPED PANEL TRUCK with no lights on at night on an unlighted highway at 70 MPH, also causing a small fire around the fuel rail, from all the twisted aluminum. Small fires become big fast and flames were 15 feet tall before Fire Dept. arrived. I, on the other hand came out with nothing beyond a bruised rib. These cars are indeed safe in major collisions, but please just take my word on that.

My only regret about the Ohio purchase is that every 10mm bolt holding splash panels under the car are rusted terribly, and I have been slowly replacing them with stainless as I work on things. Next set will be when I drop the front bumper to replace a parking assist sensor or 2 that's failing. They really do use salt in the midwest still, and unfortunately there are plenty of steel parts in front and rear subframe, even if the suspension is mostly aluminum. Next time I look in Arizona!

Thanks for all the help. This one is in great shape, my troubles are few, but with the forum, I should get these few niggles squared away.

 

Could it be the locking pin in your VVT?

 

That is an interesting thought indeed. I wonder, can you suggest a diagnostic method? The loud click happens at odd intervals, but often enough. I thought of a stethoscope, but I am not trying to deafen myself!.

I suppose I could simply put a ratchet extension or similar against it and feel the event though it, it would certainly be detectable. I did replace both vvt seals as normal maintenance when I got the car last year. They were both weepy, and that put them right as far as keeping things dry. How does the locking pin operate normslly?

By the way, that intensive thread on crankcase venting spun my head a bit. Quiet unusual solution Jaguar used, at least in my automotive experience. Explains why the one time I drove off with my oil filler cap sitting on the plastic cowl cover, I had a horrible running car, lol! Fortunately, I didn't lose the cap, but felt pretty foolish seeing it sitting there when I investigated the issue a few minutes later.

 

Ray: did you ever end up installing the oil catch-can, if so, where would such a thing be placed, off the tube running from the "pcv" to throttle body? If so, did it have any effect on your intermittent exhaust smoke events? I absolutely detest the idea that my intake is filthy with oil (potentially) and that it is so by design, sort of. Does not strike me as "world class engine design" even if the earlier 4.0 liter AJ V8's made Wards 10 best engine design list at one time. This in spite of nikasil cylinder liners (fail) and plastic secondary cam chain tensioners (double fail) Obviously Wards list had a low bar for inclusion. I am not actually beating up on the AJ V8. The AJ34 was a sensible sized engine, though the 3.5 seems a tad small for a full sized luxury sedan, even a light one such as these. Personally I think it's a terrific mill, and at 170k miles my previous car ran strong and reliable This is my "do over" car, bought with 89k miles, some 18k less than where I started with the other one.

 

From the little I know the VVT is actuated or operated by oil pressure which leaks away overnight; that is why you get that 2-3 second 'Death Rattle' at startup! I also get a very loud clicking noise when the engine is cold and I am given to understand that this may well be a lack of oil pressure (until it builds up) failing to engage the locking pin? Others, more knowledgeable than I may know much more.....

 

Returning blow-by products to the inlet for combustion is a legal emissions requirement, so I very much doubt that this practice is unique to Jaguar? It seems to me that most of the emission control measures on all engines in more recent years are designed purely to reduce emissions, not improve performance?
I did fit an Oil Catch-Can, but I found it seemed to worsen the problem and so removed it.
As I understand it (I did not sort this myself but had this work done for me by a mechanic in a nearby and cheaper Emirate) my smoke problem was caused by a cracked Drum in my transmission which would expand when hot and periodically jam, thus confusing the ECM into believing that I had suddenly changed from 6th gear to 1st and attempting to fuel the engine accordingly! Not sure about the veracity of this explanation, but in any event, the reconditioned transmission I had fitted nearly a year ago seems to have solved my problem which has not reappeared.
Personally, I think this Jaguar engine is superb and my only complaint is that (no doubt due to Ford's input) too much plastic has been used in areas subjected to high levels of heat.

 

But isn't Ford the reason the prices all drop on resale????????????

 

Has anybody ever opened up an x350 PCV valve / oil separator to see exactly what they are supposed to do? Is there ANYTHING happening at all in there? I suspect its just an oil separator but I'd like to know before I replace mine.

 

There is no valve in the oil separator or "crankcase vent valve," at least not one that closes all the way, so it rarely needs to be replaced. i haven't cut one open, but it's probably just a typical oil separator.

However, off the top of my head there are two rubber O-rings on the stem that fits into the camshaft cover and those O-rings harden and leak. Also, the O-rings in the quick-connect fittings on the corrugated plastic part-load breather hose also develop leaks. If your breather hoses are not cracked, the O-rings can be replaced with a bit of fiddling.

What are the symptoms you want to resolve?

Cheers,

Don

 

I cut one open because like many of you I was confused as to how the system works and being familiar with how a PCV valve works on typical American cars I quickly realized that the flying saucer pvc valve on the right valve cover did not act the same way as a conventional valve. The conventional valve has a spring on a pintle that will rattle when you shake it. The conventional PCV valve will suck up combustion gases at part throttle and idle and I believe it will close at full throttle but it really depends on the design of the particular valve for the particular engine its used in . The rattle is caused by the spring on the pintle and is designed to shut the valve in the case of a backfire.

So knowing all that and knowing that my flying saucer pvc valve did not rattle and seemed to allow flow in both directions I had to open it up and what I found was a diaphragm and a spring which did some metering but did not seem to close during vacuum. it seemed to only close if there was a backfire. I wish I still had the valve that I cut open to show you but I threw it away

Oh yeah and for the guy who says that PCV valve is redundant I hate to tell him that he’s mistaken because PCV does not stand for positive crankcase valve.
PCV stand for positive crankcase ventilation So adding the valve at the end is appropriate and not redundant.

all in all I believe the crank case ventilation system on the Jag motors are a full vacuum type system full vacuum from the intake is applied to the crankcase. but it relies on all of the various O ring seals and gaskets to along with a small drilled opening in the port on the left valve that connects to the intake tube behind the maf to create a metered flow into the intake elbow. that small drilled opening in the left cover is why we don’t have massive vacuum leaks with the flying saucer valve. it appears to be wide-open all the time But flow is limited by the small drilled hole

 

Don, are there specs for these two rubber O-rings on the PCV stem, as well as the O-rings in the quick-connect fittings, or do I just eye up size. My situation is that I just did the Front Engine (Timing) cover on my 04 VDP and while that was certainly a lot of fun, all went back together just fine, but I have the P0171 code popping pretty quickly. All of the hoses don't appear to be leaking, so I figured I'd start with the O-rings you mention here and on other thread.

Thanks,

Glen

 

And just to be clear, the engine cover was leaking at the gaskets and crankshaft seal, so I replaced them, as well as both valve cover gaskets.

 

Hi Glen,

I may have recorded the O-ring sizes somewhere but I am in the process of moving so I don't have access to my records. Off the top of my head, I would guess the O-rings are in the range of 16mm internal diameter by 2 mm cross-section, plus or minus. I keep assortments of metric O-rings and just match them up by eye.

Cheers,

Don

 

I have replaced these on x350 and Audi A8 engines. The PCV/AOS look identical. On Audi’s they honk like a goose when gummed up with oil sludge.
Replaced one on A8 with a 20.00 knockoff. It started to honk in about 1000 miles. Cleaned the original, full of sludge, and still running it. They come apart for a thorough cleaning.
Never heard anyone report honking on a x350. But put an OEM on as further proof of OCD.

 

Thanks Don/Panelhead. Changed out the O-rings and still getting the p0171 code. I have a basic Innova and the code pops on that pretty quickly. After letting the car run a little longer, the CEL comes on and the dash reads Performance Restricted. I think that's because the code has generated a second time. I saw Don's suggestion to get the Torque app and an EL127 device to look at more in-depth readings that might help in resolving this. I'll post back here when I have more info.

Thanks again,

Glen

 

Hi Glen,

Other common Bank 1 leak points include the variable valve timing solenoid seal, the camshaft cover gasket, and the breather pipe to crankcase vent (PCV valve) O-rings. You've replaced the cam cover gaskets, so that shouldn't be your problem. If you can see oil leaking from the VVT seal, air is being sucked in under engine vacuum.

It is also quite possible that Bank 2 is also running lean due to an upstream leak or other issue that affects both Banks, but only the Bank 1 DTC is being triggered. Common issues include cracks in the air intake pipe, especially at the accordion folds or at the ultrasonic welds where the Helmholtz resonators are attached. Also, the Mass Air Flow Sensor does not last forever. A couple of times I have resolved all the leaks I could find with a smoke machine but the lean running persisted. Replacing the MAFS with a new OEM Denso unit solved the problem. It's worth trying to clean your MAFS first. I use about half a can of MAFS cleaner spray to really flush it out. The condition of the Intake Air Temperature Sensor bulb will give you a clue to the condition of the hot wire. If the side of the IATS bulb that faces the air filter is visibly dirty compared to the other side, your hot wire is probably also coated with gunk.

Cheers,

Don

 

Got the EL127 bluetooth device and used the Car Doctor app on my phone. Turns out that while my Innova only generated the P0171 code, the app is also generating a P0174 which may or may not mean the issue is upstream. What scares me is the STFT and LTFT readings that are at or near maximum for the readout. I have cleaned the MAF sensor with an abundance of CRC cleaner, but the condition remains. I did remove the intake pipe/accordion fold/resonator placed vacuum and pressure on it with no air leaking by, so I don't see that as the issue. Also installed a new Beck/Arnley PCV/OSV with no change in condition. Thinking next step is MAF sensor and if that doesn't do it, into the shop for a smoke test.

All help is greatly appreciated.

 

At 3.84 g/sec at 650 rpm, your MAFS signal does seem a little on the low side. What happens to the signal when you increase engine speed to 2,500 rpm?

I have resolved P0171 and P0174 on a couple of X350s by replacing the MAFS with a genuine Denso part after resolving all detectable air leaks, so you may be at the point where it makes sense to replace it even if it isn't the entire problem.

Cheers,

Don