Hello to all,
Would any of you guys please help with answers to the following?:
(1) Does the Air Bleed Valve serve the purpose of a one way valve, holding pressure in the fuel supply line? The THING is located in the trunk, next to the fuel filter.
(2) Upon removal, how do I check that it is working the way it should?
(3) Is this also known as the Check Valve? If not, where is the Check Valve located on an XJ6? Your help would be greatly appreciated.

 

are you referring to the Fuel VAPORS Pressure Release check valve of the Fuel Evaporative System?

I don't know about Australian XJ-6, but in USA XJ-6, there is a 1-way check valve located in the front, Passenger Side wing, (Left Hand Drive cars), located before the Charcoal Canister and mounted to the inner wheel housing panel; To see it you have to raise the front so the tire & suspension go down.

it is a black, plastic check valve connected to a steel line coming from the tanks.

 

The check valve *screws into* the air bleed valve. Item #5 in this illustration:

Fuel Feed Pipes and Hoses-Trunk - Parts For Series III Saloon | Jaguar Classic Parts UK

Remove the check valve and blow thru it. You should be able to blow thru it in one direction only

Cheers
DD

 

this little valve has been causing trouble lately!

 

Thank you Jose. No, I was referring to the valve , next to the fuel filter in the trunk. It is connected to the fuel pump, to the filter and then to the fuel line.
Many thanks Doug, exactly what I was looking for. I did not realize that the non return valve could be removed from the assembly.
I am still struggling with the same problem. Why does the engine on my jag take that long to fire? I renewed the fuel pump with a brand new one which I purchased from the UK. Just what I thought, releasing the fuel pressure before fitting the unit was unnecessary as there was absolutely no pressure in the system. So, there must be a leakage somewhere. I intend to check the non return valve for proper operation and then renew the fuel pressure regulator. Am I on the right track?

 

How much time had passed since shutdown? Just wondering



You might be on the right track. A fuel pressure test would be very useful here. Can you buy, borrow, or rent a gauge?

But....

Even if the pressure bled completely down to zero the fuel pump (especially a new one) can and should repressurize the lines very quickly.....about 3 seconds or so at the most. If you're having to crank the engine for longer than that then it probably isn't a pressure bleed-off problem.

The regulator is a possibility, yes. A pressure test would verify but they're not horribly expensive or hard to replace if you wanna take a guess.

How long DO you have the crank the engine? Is the problem sensitive to engine temperature? Any black smoke on start up? What else has been checked or replaced, if anything?

Cheers
DD

 

Doug, many thanks for your useful comments. It hurts hearing my jag battling so hard to fire. Not to mention the wear of both the starter motor and the flywheel. I have not started the engine for the past two weeks on purpose as I want to make sure the fuel pressure problem is solved. Over a year ago I purchased a Bosch fuel pump from a guy in the UK. Although I was assured then that it was new and unused, it arrived without a box and with no instructions. There was no difference in the engine behaviour when I fitted it. So, I purchased another brand new unit from a reputable UK jaguar parts supplier a few months ago. I fitted the second pump only yesterday. After your suggestions this morning, I removed the Air Bleed Valve from the trunk and unscrewed the check valve. It is still OK as I could only blow air from one side. The air bleed valve is now back into place. I have ordered a fuel pressure tester a few weeks ago but it is taking an awful lot of time to reach me. I am so certain I have a fuel pressure problem that I went a step further. This morning I ordered a brand new Bosch FPR from a well known local jaguar supplier. I hope to have it here and fitted by this coming Friday. After all this I am sure the pain will be over. I certainly will keep you posted.

 

Hello to all,
Received my new FPR yesterday, Monday. I was unable to renew it as the big nut securing the unit to the bracket on the fuel rail will not budge. Obviously the previous owner has done some work on the fuel rail as one of the mounting bracket has been welded back to the rail. I feel sure the FPR has then been fitted using a vice or similar prior to reassembly. So, the fuel rail has to come off. Any ideas or suggestions on how to disconnect and reconnect those six extra short hoses connecting the fuel injectors to the rail without damaging or disturbing the injectors? Your help would be greatly appreciated.

 

There are a couple different approaches. The best way, in terms of minimally disturbing the injectors, is to remove the hose clamps and carefully slice the hoses so they come off the injectors quite easily. Simply use new hose on reassembly....which isn't a bad idea of the hose are more than 5 years old anyway.

Or.....

Remove the injector hold-downs (2 nuts each) and the injectors will come away with the fuel rail, hoses and all. The risk here is disturbing the injector seating cups which, if original, are best left undisturbed unless new ones are at hand.

Cheers
DD

 

Thank you Doug. I would rather go for option 1. Removing the injectors means more work and more headache. Furthermore, I have no new seals and cups at my disposal. After removing the hose clamps and slicing the hoses at the injectors as you suggested, how much pressure can I use to pull the hoses out? If I pull too hard, will I dislodge and pull the injectors out as well? Upon fitting the new hoses, will I push the injectors in if I apply too much pressure pushing
the hoses in? I apologize for these questions but I have absolutely no idea how the injectors are fitted.

 

No worries, the injectors are positively held in place by the hold-down plates. They won't come out inadvertantly.

A slice or two in each hose will allow you to remove them from the injectors with just a little wiggle or two.

On reassembly make sure to use *fuel injection* grade hose. Standard hose won't take the pressure. Any auto parts shop will have it.

Cheers
DD

 

Does the car take ages to fire when hot or cold, or only when cold ? Reason I ask is that there is a cold start injector. If this is not working, the engine will take much longer to fire, but run OK when started, and also start OK when hot.

 

Thank you Fraser. The engine takes ages to fire both when hot and cold. The last time I checked the cold start injector was performing well: an even spray of petrol. I have just renewed the fuel pump and I am in the process of replacing the Fuel Pressure Regulator with a brand new one. I hope this will solve the problem.

 

If the injector hoses are really hard to loosen or if you are afraid of cutting into the hose mountings; try to melt the hoses off with help from a propane burner (when removed from the car of course!).

Cheers/
Mattias

 

Hello to all,
For health reasons I was unable to work on my Jag. Now that I am back here is what I have done so far:
(1) Replaced the fuel pump with a brand new one.
(2) Removed the fuel rail, cleaned, replaced the FPR with a brand new one renewed all fuel hoses connected to the injectors. The engine will crank but will not fire. I read an article by Doug regarding cold start priming. With the gear selector in DRIVE I activated the ignition switch in the start position for approximately one minute. I could hear the fuel pump working. The engine will still not fire. I disconnected the fuel hose to the fuel rail and cranked the engine. There is NO fuel coming. Did I miss something? Is there a switch in the trunk to reset the system? I am really at a lost here. Can anyone help me solving this problem?

 

Just a thought similar problem I found that the wires in the temp sensor at the front of water rail where broken off and the plug had look like it was cooked. Changed it over with a new plug reconnected the wires and away she fired.

 

A couple quick thoughts.

-The fuel filter is 100% clogged.

- There is no fuel supply TO the pump. Empty gas tanks, or a clogged changeover valve

- Pump installed/plumbed backwards? Not even sure if this is possible as the inlet/outlet nipples are two different sizes, as I recall.






There is an inertia switch that disables the pump circuit completely but, since your pump *does* run, the inertia switch is obviously not the problem

Cheers
DD