My car has the updated purge valve with the remote vent filter kit. Did some testing and have a question.

The vent should not draw air when the purge cycle is off, correct?

After some testing have come to the conclusion that mine is stuck open. FYI, it affects left bank fuel trims, tested by plugging the line.

Used IDS to check tank vacuum with cycling, verified no blocked lines or leaks. No codes or pending and all ready have been set for a long time. IDS even says the valve is it.

opinions appreciated, thanks.

 

Hi Cor,

Your description of the remote filter makes me think you are not describing the purge valve but rather the canister close valve (CCV, also known as the canister vent valve), Part 7 in the diagram below. Its remote vent filter is Part 11. The canister close valve opens periodically to vent air held in the carbon/charcoal canister into the atmosphere. It is located at the rear underside of the car next to the carbon canister(s):




The purge valve, Part 21, connects between the carbon canister and the engine intake with no vent in the circuit. Under certain running conditions, the ECM pulses the purge valve open and closed like a fuel injector to meter fuel vapors from the carbon canister into the engine intake. The purge valve is located inside the front left fender aft of the wheel, inside the wheel arch liner.

A stuck-open canister close valve will typically cause lean running codes in both banks. A stuck-open purge valve can cause either lean or rich codes, depending on the fuel vapor load in the canister, but it also will affect both banks similarly. It is possible that your left bank has one or more other air leaks that makes it more prone to triggering the lean code. Common leak points are the breather hose O-ring, the oil filler cap seal, the camshaft cover gasket, the spark plug tube seals, and the VVT solenoid valve seal. Unmetered air is inhaled under engine vacuum.

You can test both the canister close valve and purge valve with a 12-volt battery or often even with a 9-volt radio battery. In one state (powered or un-powered), you will be able to blow through the valve. In the other state, the valve should be completely closed.

Cheers,

Don

 

Info about CCV.

 

Thanks Don,
I am definitely referring to the purge valve located in the left fender well. Mine has a vent since it is the upgraded unit. A lot of other OEMs had issues with spiders nesting in the vents and with corrosion in general, hence the remote filter and rerouting to an under hood (sorry, bonnet) location.
The CCV is working fine as it is normally open and only closes for the pressure test cycle which has been verified through IDS.
The purge valve should be closed when unpowered and not draw air through its remote vent during the "purge off" cycle.
Fuel trims are affected on the left bank due to how the air enters the manifold from the system. My engine and seals were completely smoke and pressure tested to rule out anything else.

FYI, the part number for the upgraded valve is LJG1515BB.

 

Let me confirm that it is, indeed, the purge valve. I had to replace mine recently, and posted a question about it, IIRC. There is a vent in the top cap now, and the related TSB shows routing a hose up to the brake booster area (LHD cars), and attaching a filter.

 

Cor,

Thank you for clarifying. I assumed you were referring to the CCV because there were many occurences of corrosion in the vent hose (see the first TSB attached). I had to go through my TSB library to find the one regarding the revised purge valve you have.

Just curious, but does your car have the carbon canister inside the front left wheel arch liner like the diagram below? The systems changed over the X100 production run and I'm trying to visualize your setup. Purge valves do not usually have a vent to the atmosphere, so I'm wondering if the revised vent is related to the tank pressure control valve function. The TSB does not explain how the vent works:




Cheers,

Don

 

Hi Don,

No, my car has the dual canisters behind the rear axle and the fueling vapor recovery system which was required after about 2000 in the USA market. My purge valve is located in the left-front fender (sorry, wing) where the earlier cars formerly had the single canister.

I have a theory as to why a lot of cars with the purge valve in the fender have issues with said valve. The cowl scupper drain system dumps water in that area leading to moisture getting into the valve vent. Actually it is a rather cool drain setup, however i extended the hoses to a direct drain to ground to keep the moisture out of there on both sides which is what Jaguar should have done.

Best, Cor

 

Cor, I think your explanation makes perfect sense.

What is interesting to me is that purge valves in general, and the original purge valve on the '01 XK, part number LJG1515AA, do not have a "vent," per se. They have an inlet hose connected to the carbon canister, and an outlet hose connected to the engine intake. The common failures were likely due to water finding its way into the purge valve case and causing the electromagnetic solenoid to corrode and seize. The plastic cap over the solenoid must allow some communication with the atmosphere, perhaps to cool the solenoid since it pulses continuously for extended periods, and this would be where the water gets in, I assume. Perhaps the cap on the revised purge valve is completely sealed and the vent hose allows cooling air to be drawn in from the engine bay out of reach of the draining water. The vent would also serve to allow condensation to evaporate.

Do you know of a technical explanation of the vent on the revised purge valve? The TSB does not explain it. Sorry for my curiosity, but I like to understand these things!

Thanks!

Don

 

Hi Don,

I believe that the "original" purge valves have their atmospheric vent under the cap which has the part # and OEM label. It is an unfiltered "hood" over the inlet on some of the used specimens which I have looked over. Have not had a chance to break one apart yet for study. Probably fine when it was in the engine bay but not in a guaranteed to be wet location. Air must be introduced from this to facilitate the purged fumes.

EDIT: just got this from a friend regarding how the original was configured: "It has a vent out of the valve body. The rubber hose
runs behind the liner (just under top of fender) to a similar filter as yours above the washer reservoir."

Trying to remember how my old one was configured...

Regards, Cor

 

Hi Cor,

As far as I understand, no atmospheric air should be introduced into the system by the purge valve, nor should any fuel vapors escape from the purge valve into the atmosphere.

When purge function is called for by the ECM, the purge valve opens and allows the engine to inhale fuel vapor from the carbon canister. Fresh air flows into the carbon canister and evaporates the fuel adsorbed on the surfaces of the activated charcoal granules. This prepares the charcoal for the next time fuel is added to the tank. The force that moves the fuel/air vapor into the engine is the vacuum (depression) in the engine intake manifold or throttle elbow. The canister close valve is typically always open except during leak detection, so there is no need for any extra air to be drawn in via the purge valve.


This is a photo of LJG1515AA. The hose/pipe configuration is from VIN A00083 to A30644, which may include your car? Note the third hose, the one without the quick-connector:




This is the parts diagram:






So Jaguar calls the third hose in this configuration a "Fuel hose," which doesn't seem to make sense, since the end of the hose has no fitting capable of holding pressure.

Here's the diagram for the same purge valve part number but for VINs up to 042775 in the "Running Loss" configuration:







In this configuration, Jaguar calls the third hose a "Breather hose." This seems more plausible, and suggests that either air is allowed to cool the solenoid, or reduces pressure fluctuations on the back side of the valve by communicating with the atmosphere (it looks like a diaphragm-type valve).

Is one of these configurations the one on your car? Is your car a California or CARB-compliant vehicle? I have only cursorily studied the differences between the standard, Running Loss, and Onboard Refueling Vapor Recovery (ORVR) configurations.

Thanks,

Don

 

Hi Don, Good points and questions, thanks.

Update, i found the old vent line and filter. Jaguar positioned it and its filter over the washer bottle, dumb. This is reasonable evidence that the upgrade's relocation is to keep it clean and dry so to speak. It would connect to that "third hose" as i have verified with an old style purge valve sample. The use of the term "fuel hose" is an old label for the type of small diameter flexible rubber hoses which were once this. They are saying that they used "fuel hose" to make the connection as a common stock part not having a specific part number.

My original thoughts on this vent were that it might take part in the pulse and reduce some of the vacuum pull by some open/close cycle or orifice. However, i am leaning in your direction that it merely serves to balance pressure on the other side of the diaphragm mechanism. This would in my case that it pulling constant vacuum as received from the throttle body connector to the purge valve means that the internal diaphragm and/or mechanism has been pierced or otherwise lost its seal to the normally closed system. Once i install the new valve, this can be verified that it is only to balance pressure in the purge control valve housing as the diaphragm shifts position.

My vehicle is the Onboard Refueling Vapor Recovery (ORVR) configuration, and all imported are also CARB compliant as there is no distinction.

If i am correct, this type of failure would be a major contributor to unexplained fuel trim issues. It does not cause a MIL or DTC or even a pending DTC for a few reasons. The post MAF air is not too much to trigger, and the loss of vacuum pressure is not enough to trigger a tank leak fail or not ready.

Additionally, this satisfies so much of the vacuum from the port that the low load breather orifice (PCV in many cars) might not receive sufficient vacuum to work properly.

I wonder how common this failure is. Essentially, if it proves with the new valve, all one has to do is plug the purge valve vent (either old or upgraded, does not matter) and see if idle is briefly reduced to near stall. Note that IDS test procedures identified the valve as failed.

Regards, Cor

 

Did somebody say, "this isn't rocket science ?".

 

Well, i took the car up to a very high altitude yesterday on a spirited drive so to say, and it did not blow up with the obvious defect. Not saying "space" levels here, just tongue in cheek in the spirit of the recent USA space efforts...

Actually and back on topic, as i expected as the road temps were very high part of the trip and with the drop in pressure due to high altitude, i did briefly smell some gasoline fumes in the cabin. This would be due to the apparently defective purge valve not providing an effective purge with the result being some vapors escaping from the canister close valve vent.

 

Update: Installed the replacement "updated" purge valve, and this allowed for some system testing and side by side comparisons.

There are major improvements in fuel trims, run and idle quality with the new valve, so the previous "updated" unit was obviously defective. Note that there were no installation issues with the previous valve; just to rule out those variables.

When the first updated valve was installed we chose not to perform the ECU update as it appeared to be operating properly and were advised that said was not recommended unless there were additional problems.

Removing the valve allows for the integrity of the lines from the tank, etc. to be tested for leaks and blockages. This was performed.

Side by side comparison, it is definitely easier to blow air through the previous valves vent, and the replacement does not draw as much air through the vent. Opening the previous valve was not as easy, so there was probably the issue of it not properly purging the system. Here is where i learned something.

The valve works by receiving constant vacuum which is released by the aforementioned vent. The electrical signal pulse closes the vent to redirect this vacuum to the diaphragm and allow the TB/PCV vacuum port to draw vapors. This is why earlier specimens of this valve created a buzzing sound. The unmetered air from the vent is part of the air/fuel management design.

If in an otherwise well sealed engine and air intake system one is receiving odd fuel trim problems, especially single bank and even idle stumbling which makes one think TPS issues, simply cap the purge valve vent and go for a drive monitoring live fuel trims and see if there is a difference. The difference in my car was astonishing. This valve can cause a lot of problems and not be the apparent cause.

The gasoline fumes in the cabin were significantly improved. The problem is still present to some degree under combined conditions of high heat and climb to very high altitude, the perfect way to test the system. My next step will be to see if the canister close vent filter is accessible to me in the trunk access. If so, i will rig an overboard discharge. If this solves the problem, my options are to consider ruined charcoal canisters or need to update to the exterior CCV vent as per the TSB.

Please see the following link from here for some general background on the problem, thanks to those who discussed it in previous years:

https://www.jaguarforums.com/forum/x...s-smell-50466/

 

Hi Cor,

Thank you for reporting your resolution. At michaelh's recommendation, I have added a link to this thread in the stickies. This discussion may be helpful to others in the future who are grappling with similar issues.

Cheers,

Don

 

My pleasure Don,

It is quite interesting the number of other issues which this problem can mimic. Just to restate and add it can seem like leaking injectors, throttle position sensor, valve cover and other engine air leaks, etc. To add insult to injury a new replacement was defective.

I wanted to verify my repairs, so after running the car with the fixes in place under a variety of conditions and monitoring the data such as long and short fuel trims, i reinstalled the not apparently defective previous "updated" valve and everything returned to yuck. Cause and effect demonstrated.

One thing which perplexes me is why did Ford create this system of a near constant vacuum leak with such an odd pulsed diaphragm switching. My 2 cents (or pence) is that they did not want to use a direct electrical solenoid valve for issue of potential spark in the presence of mixed fuel vapor and air. It is the only reason which makes sense.

Once again i will restate that it is easy to test for this issue by plugging the valve's vent, driving and looking for major problems to go away. This cannot be performed for too long obviously, but enough to get an idea.

Wishing all of the best and happy motoring to everyone.

And, thank you for all previously posted information which helped during the journey.

Cor

 

My recollection is that contemporaneous Fords and other brands use electrical solenoids in the engine compartment with no issues, and there are plenty of other potential sources of spark in the X100 engine bay, including all those relays in the power distribution boxes. I wonder if the design has something to do with CARB requirements at the time?

 

Way above my pay grade. The only shot in the dark is that the vacuum allows for a pulsed feed of the vapors. Drawing too quickly might pull more air than fumes from the canisters and also contribute to too much post MAF air.