California car has vacuum control activated by a mystery small vacuum line going under the manifold. No electrical connection to purge valve. Should it have a non-vented gas cap? Air rushes in or out when I remove it. Code comes on when idling. No vacuum leaks that I can find with smoke test. FF26 means to lean. (poor feedback control in lean direction) Oxygen sensor replaced, Idle air control valve, and MAF sensor with matching numbers one from a wrecking yard.
Purge valve, I believe is located next to your charcoal canister.
If it’s where mine is located, in the 96 with the 6 cylinder engine, then it’s in the drivers side front wheel well. You can take a look and see if the purge valve responds to a 12v feed. Check to see if the harness is giving you 12v when the key is turned on.
There might be a fuse associated with the valve?
It could also be a failed Rochester valve.
What engine have you got? AJ6 or AJ16? Still v12? You may be looking at the wrong clues… Check injectors, conditon of fuel filter to start with. Disconnect and blank all the vacuum ports / reset codes and try again.
It’s a AJ6. code FF26.I’ve fixed any vacuum leaks. California car with a different purge valve, no electrical connection, just a small rubber hose going up under the intake somewhere. New GM egr valve. new idle air control valve. junk yard MAF sensor, exact part number match from ebay. New oxygen sensor. My purge valve is not available any where I look. I bought a US one that is controled by vacuum, same hose sizes. Haven’t tried it yet. New intake air sensor. It all started when a shop didn’t put the upper radiator hose on correctly, and it blew off. The engine sucked up a little coolant. I guess I could try blocking off the main vacuum line going to the cannister. I’ve got a few more vacuum tests to do, can’t drive it much, can’t smog it and get my paid for tags.
Your car doesn’t have a purge valve by the charcoal canister?
Part # DBC4301
Have you ever inspected your charcoal canister?
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It has one, vacuum activated for Calif. I found a open T in the line going to it last night. I haven’t messed with the canister yet, afraid it might be full of gas. Gonna measure the vacuum on that mystery line today, using that open T. No electrial
Maybe that’s the Rochester Valve? CBC7714? That should be connect to one of the two bottom ports at the charcoal canister.
The purge valve should be connected to the other bottom port of your charcoal canister.
https://parts.jaguarlandroverclassic.com/parts/index/part/id/278.910.1515.5190.22871/brand/jaguar/
I’m not aware of any changes Jaguar made specifically for California cars.
Again, you may be focusing on wrong bit. To start with:
- Is your engine having any obvious problems / rough idle, power loss, bad start on warm etc. (code alone means nothing…)
- I’m not from California, however - I’ve met many junkies…
Can you describe what on earth they’ve put under your bonnet to get green badge, please? Catalytic converter - for sure, EGR - for sure, air injection pump is there/was ever there? - Your lambda tells ECU that the fuel-air mix is lean. I can see that you’ve replaced everything already - hoping to find the source of your trouble (see pt.1). Your lambda may be right or think it’s right.
- I’ve mentioned earlier - you may be focusing on wrong bit. You’ve spent fortune and years of time to remove leaks, have you checked your fuel pressure and ignition system?
Starting from fuel filter and sump tank filter (if you have one) is a basic thing. - After you’ll answer pt.1 we can go to conclusions…
Thanks so much for the diagram. Now I know where the purge valve is, I found it under the air cleaner. That pressure relief valve at the top with 3 hoses, is what I thought it was. No vacuum going to it’s control line, open T in that line. I have a purge valve I ordered from parts geek. I’ll try installing that. A lot of the parts in that diagram are no longer available. I have an american part that could replace that pressure relief valve, if necessary, even though it’s getting no vacuum control. Thanks so much. I would hate to have to part out this beautiful and good running car.
Fuel filter replaced 3 years ago. Can’t hook up fuel pressure gauge. Car is running very well, at speed and idle. Just found out where the vapor cannister valve is located, have one, will replace today. The thing I though was california is the pressure relief valve on top of the cannister, it’s getting no vacuum, open T in the line going to it, no vacuum cold or hot. That sump tank filter, in gas tank? Big job to replace, special tool and drop the tank.
What is your current car usage, guessing none to zero?
Only 3 years ago… Ehmm…
When the error occurs? Righ after reset? Some time after reset? Got some photos from under the bonnet? Not sure where the pressure purge solenoid is located in emissio-controlled versions, in UK ones it’s righ next to the fuel tank / in the boot.
You can diagnose airlock by opening the fuel cap after some time on idle - blows out - good, sucks air in = airlock. Easiest way to eliminate your beloved purge problems - leave fuel cap half way/varely engaged and take it for a ride (error code still there?) Reset the codes and run the engine, unplug MAF sensor - what error code do you have?
Big jobs are your ordinary day now (well done, XJS Owner). With car stood still you will have plenty of shinybflakes in your petrol. Suggesting investment and full drain of old fuel / refill with fresh one.
So, when you’re getting the code exactly?
I use the car at least once a week. There is blowout when I losten the cap. I’m replacing the purge valve next, then that pressure relief valve, if that doesn’t do it. The code comes on after I drive it hard, then let it idle.
If there is a blowout, your Rochester Valve (pressure relief valve) has probably failed. Thats the one that needs a vacuum to open while the car is running.
Do not toss it. It can be opened and cleaned and it may work good as new. Do a forum search on Rochester Valves. I have found that the alternate part numbers do not work well, and will cause problems. I have installed an alternate venting method, but that is a story for another day…which you will probably run across…if you do a search.
The purge valve takes a harness connection. I’m not sure when it opens, but test it with a 12v source, doesn’t matter which side gets the + or -. Blow through it before you energize it. There’s an arrow telling you which way the air goes, but it should work both ways. You shouldn’t be able to blow through. Then add the 12v source and you should have no problem blowing! Test confirmed on purge valve.
That rochester valve has no vacuum going to to the control port, can’t see where that line goes without pulling the intake. I have an american one I bought off amazon. I pulled the purge valve and bench tested it, there was an open T in that line since I’ve had the car. Info I’ve seen says the purge valve is normally open. Mine is. When I connect the 12v, it’s closed according to my vacuum tester. The replacement Bosch purge valve has a different diameter exit pipe than the factory one. I could use a new hose to the tank, but I’m replacing a working valve.I wish I could test the fuel pressure. New regulator installed. Code comes on after driving it hard, and letting it idle. (too lean)
Have you tried capping that T to see if the vacuum will make it to the actuator on the valve yet?
And I get that an unsolved problem will prevent you from renewing registration, but PART IT OUT?!?!?! There are 40-something other states that don’t bother with California’s nonsense regulations, at worst you could sell it out of state.
I ran a vacuum line to that rochester valve, and got it working. No rush of air when opening the gas, new purge valve & hose, also. Still get the dreaded FF26 idling after a drive. There is a mystery vacuum hose going through the firewall on the right side. I’ve read the ECU is under the right dash or tunnel. If it goes there, that might explain things. I can’t force smoke down it, but if I hook it to vacuum, it drains so much the EGR stops working, that’s why I have it blocked off. When the rains are over Thursday, I’ll dig in there, and look for cracked hose. Must be a check valve in line, even though there’s one ahead of the line on the firewall. Good idea about selling out of state. It’s a Calif. car with no rust and orig paint. Wish I could test the fuel pressure, has new regulator.
Can you post a picture of this mystery hose?
Here’s the picture, check valve on the right where vacuum comes from the manifold. I have it blocked with an insert so the EGR works. It must either go to the coolant recovery tank under the fender well, or to the ECU under the dash. That tank, has a plugged drain, I disconnected it from the coolant filler tank.
Charles,
You do realise that purge signal is given at certain engine temperatures?
Was your Xjs stood somewhere for a long time? How you two fell in love? (Purchased from good source? Non runner? Barn find? etc)
