XJ6 s2 fuel not getting to carbs and cylinders
 

Hi everyone,

I'm a new owner of a 1975 XJ6 with the 3.4 engine. I don't know too much about the past of this car and what problems it had but I know it's been sitting for 9 or 10 years.
I wanted to start the engine so I removed the spark plugs and sprayed all cylinders with some fogging oil (I know you do that to engines sitting for 6 months or longer), left it for a week to soak in and then turned the engine to change cylinder position, sprayed it again and left it for one more week.
The engine isn't locked and the starter works fine.
There is enough oil and it looks quite good as for so much time. ddddddddddd

Yesterday came the time when I wanted

Karl,

Firstly, welcome to the Forums.

When time permits, please do an Intro in the New Members Area,it keeps the "boss" happy.

1975 possibly?? has submerged pumps, as in one in each tank. and I reckon they have died after that time. Generic pumps are available.

If it has the single pump in the boot, under the cover panel rearward of the spare wheel, same scenario I reckon. Also, generic pumps are available.

You may not hear the pump/s when teh ignition is in the ON position, as some markets have an oil switch (reverse polarity) as the earth for the pump relay, sooooo, NO oil pressure, NO pump working. Simply earth that switch wire anywhere convenient, and the pump/s will operate whenever the Ign is in the ON position. I did this to all my Series Jags, as that switch was notorious for failing, and much hair pulling took place, until that sucker was found.

description and pics
 

[QUOTE=karlheinzr;2086032]Hi everyone,

I'm a new owner of a 1975 XJ6 with the 3.4 engine. I don't know too much about the past of this car and what problems it had but I know it's been sitting for 9 or 10 years.
I wanted to start the engine so I removed the spark plugs and sprayed all cylinders with some fogging oil (I know you do that to engines sitting for 6 months or longer), left it for a week to soak in and then turned the engine to change cylinder position, sprayed it again and left it for one more week.
The engine isn't locked and the starter works fine.
There is enough oil and it looks quite good as for so much time. The level of coolant is also correct.
All spark plugs are ok.

Yesterday came the time when I wanted to start it.
I hooked up an external fuel system that I made from a Hardi electric pump and a hose connected to the inlet on the metal line going to the carbs. The fuel line going to it was already disconnected from it. Of course I disconnected power from both of the pumps in the rear.
This is my pump:
https://cimg5.ibsrv.net/gimg/www.jag...f3c7a87485.jpg
And here the connection of the hose to the metal line:
https://cimg9.ibsrv.net/gimg/www.jag...a7d2885413.jpg
https://cimg4.ibsrv.net/gimg/www.jag...8c9d6b4487.jpg

When I turned on my pump there was a problem - the fuel went to the end of transparent hose for like 3 seconds and then it went back like to the half of it and was moving a few centimeters back and forward. There was also a bit fuel left before the connection to the metal line but it didn't move at all.
After disconnecting the hose from there and testing the pump it works great and pumps to the very end of the hose.

The engine cranks great and I think it would start but because of fuel not getting to it.

I noticed one thing and I have no idea why would someone do it: the line going from the metal line up to the AED is disconnected and clogged, the connection on the AED is clogged as well. Has anyone got an idea? Can that be the reason for the problem?
https://cimg1.ibsrv.net/gimg/www.jag...59c58e2fbe.jpg

I'm sorry for the lack of my knowledge but this is my first classic car ever (not first Jag at all) and I've never had any experience with them at all.
I hope you can give me some helpful advice. Thanks.

I'm sorry but I haven't finished my previous post and that what I wrote now is the precise description of my problem

OK, mud clears a tad.

They look like HS Series SU carbies, and fuel in that line is good, and that feeds direct to the jets/s.

The AED blanked off is normal, they were a PAIN from new, and if they are HS carbies, the manual choke conversion is simple.

I suspect that the pistons inside the carby bell tops are seized, and they WILL be in the "full down" position after all these years, then the fuel has NO way of getting past the needles and into the engine.

Remove those bell covers, one at a time, and clean all the residual crud and goo from the piston circumference and the inner bore of the bells.

That will give the engine half a chance of starting.

After all those years, anything fuel related will be very dried out, and jammed up. Lots of pre cleaning needed.

Yes, after some googling I also think these are SUs.
The manual choke conversion seems to be quite popular among owners of such Jags.
I'm just wondering: if those pistons weren't seized, the fuel would be getting into the engine so would start with the AED disconnected like it is in mine one?
I'm also wondering if those seized pistons can be the reason for fuel not wanting to go to the end of my rubber hose and up to the metal line? Or is it because of some air being in the hose? I don't think the pump is to weak because if it can pump fuel from the very rear to the very front of the car then why can't it pump a few centimetres up to the carbies? It didn't have any problem with pumping fuel to bigger heights when the hose was disconnected from the inlet at the carbs.

I have no idea how they're called but I was also thinking of opening these 2 things if it's possible and looking if there's some goo and crud too.
https://cimg9.ibsrv.net/gimg/www.jag...71bf673412.jpg

Many things on a fairly long list.

After those years of sitting, the residual fuel evaporated, leaving a whitish residue in most cases.

This will block the fuel entry to the bowl, Needle and Seat, AND, the flow to the jet at the end of that spiral wound supply hose.

The piston in the "full down" position, as in sitting on the Jet Bridge, effectively closes OFF the fuel, IF THERE IS ANY, from getting sucked inside the engine on the Intake Stroke.

I suggest:

Remove the tops of the fuel bowls, and clean the gunk out, particularly the small hole at the bottom, where that Spiral Hose begins it journey.
Remove the Bell Covers, and clean them thoroughly, and the pistons, then do them again, as their cleanliness is critical to operation integrity.
Refit the bowl tops, switch ON your pump, look down at the Jet Bridge, and note the fuel "sitting" inside that jet, about 1/4" down from the tip. If this is so, GOODO. If fuel "runs" out of the jet, then the float level is TOO HIGH, or the Needle and Seat is NOT closing the fuel flow as designed. Probably the latter.
Once the fuel level is obtained inside the Jet, refit the Bell Covers, fill the damper tube with ATF oil, and "go for start".

There are NO short cuts here. After 9+ years, anything related to the fuel system is going to need attention, fact.

I am ASSUMING you have a good FAT, BLUE spark AT the actual spark plug??

Yes, I do get some good spark on my spark plugs.
Thank you very much for all your advice, Grant :icon_worthy:

The problem is that the car is at my grandfather's village house which is about 200km from the place where I live. I go there and my grandfather also does every weekend when there is good weather. Now it's actually every weekend.

So I will do what you suggested me to do during that time and see how it goes with that. I'll let you know about that then.
Of course I can't forget about adding some photos too.

Just one more question: the ATF for the damper tube can be the same Type F ATF as for transmission and power steering?

Now I understand.

Spark like that is GOOD.

ATF is just short for ANY Auto Trans Fluid, and the damper on the SU is NOT fussy at all.

Take your time, ONE item at a time.

9+ years makes things awkward, as there is so much that needs attention.

You will sort it, they are simple cars, really.

So,
first of all sorry for my late answer but unfortunately I've been really busy during past few says and didn't have any possibility to answer. Now I do.
Last weekend I did what you suggested me to do and there are some results.
I do have a few photos. First my float chambers before cleaning:
https://cimg3.ibsrv.net/gimg/www.jag...735c97be3a.jpg
https://cimg4.ibsrv.net/gimg/www.jag...29ffe019bd.jpg

I cleaned all that gunk sitting on the bottoms of them and those holes going to spiral hoses as well and after that they were clean just like the walls of the chambers. The walls were actually already clean when I opened the top covers.

I also removed the belly covers, springs and pistons from my carbs and cleaned them. There was some dirt inside the carbs so I cleaned that as well.
Here is my right carb and its parts before cleaning:
https://cimg6.ibsrv.net/gimg/www.jag...de20c27624.jpg
https://cimg4.ibsrv.net/gimg/www.jag...bfbe4dc533.jpg
https://cimg2.ibsrv.net/gimg/www.jag...694f286bf7.jpg
And here are the left ones:
https://cimg9.ibsrv.net/gimg/www.jag...6a9ca0047e.jpg
https://cimg0.ibsrv.net/gimg/www.jag...d35921495f.jpg
https://cimg7.ibsrv.net/gimg/www.jag...545b2aa27f.jpg

After cleaning I put the float chamber covers back and switched my pump on. First it was the same with fuel not going through the whole hose but after few seconds it actually started going through it up into the metal line and the bowls. My pump has some special control system that adapts the pump's work to the fuel consumption at the moment. So I noticed that it started to work slower and slower and then started just ticking. And there was fuel in those 2 holes what you wrote me about. I turned the pump off and put the pistons, springs and bell covers back together. I tuned my pump back on and tried to start the engine. What was surprising, at the first attempt it started but only for 1 second and then it immediately died. It was the same at every attempt. But the engine sounded as it would be getting fuel when the starter was working.
Now comes the question what can be the reason through that.
I had starting fluid but I didn't use any of it and I think I could have put too little ATF in the damper tube. I don't know but can that be the reason?
Another thing I suspect but I'm not sure about is the AED. If mine one is disconnected, should the engine still start and run without it? I have no idea whether my AED is good or not but if someone has disconnected it then ther probably was some issue with it.

Firstly, WELL DONE, I am impressed with the end clean up.

In those snaps, 2nd to last, the tube (jet) is sitting FLUSH with teh bridge. So, the piston, and its internal needle are effectively closing of fuel, hence the run and stop. It is what we call too lean.

Down the side of each carby is a threaded screw, "mixture screw", and a locknut, and if you look carefully, you will see that one of them pushes on a fork, that raises and lowers that jet inside that bridge.

I ALWAYS set that jet 2mm BELOW the bridge face. This is NOT spot on, just an eye gauge, and will have that jet low enough to allow fuel to pass the needle, and enter the engine and fire. Further adjustments of that "mixture" can be done later when things settle a lot more.

I have some carby diagrams in my shed, and will find them tomorrow, and repost with "mud maps" to assist you here.

FOUND IT ON THE LAPTOP.

In that attachment, screw #2 is the "mixture screw", and SLOWLY turn it DOWN until that jet is below that bridge as I said above. Leave the locknut loose for now, as adjustment of that screw will be required very soon. DOWN for more fuel, UP for less fuel.

You are close, very close, it just needs some extra fuel.