Injector & fuel rail service - what size fuel line and vacuum line

I decided to start a new thread instead of working off the fulcrum / IRS build…

I’ve got a couple injectors that are leaking on the grey XJ and I’m going to pull the fuel rail off of the spare XK6 I’ve got kicking around. the plan is service the injectors and fuel rail from the spare and install on the grey XJ6 then repeat on the green XJ6.

Here’s the question.
short version
what size fuel and vacuum hose / line sizes will I need?

longer version
I typically like to have all of the bits I’ll need to perform a job before I commence. Naturally there are unforeseen items that need purchasing after I get started The whole layers of an onion scenario. I try to minimize that if possible. If I’ve got all of the bits on hand, it’s very likely a project will be completed in a timely fashion. otherwise it’s a case of “look Squirrel” - off on another tangent. Kinda like these posts.

Jag parts around here are pretty much non existent so nearly everything needs to be ordered online.
I’ve got the 3 sealing o’ rings as well as the plastic thingies that break when an injector is service.
I’d like to get a spool of fuel and vacuum hoses / lines.

Yes I could pull the old one off, and measure. but it’s in storage surrounded by other XJ parts and two XJ-S’s. when I pull it out I’d like to start on the project as well.

Side tracked
Does the secondary butterfly (removal) in the intake on the Series I & II apply to the Fuel Injected Series III’s? If so, I may as well pull the manifold and perform that mod as well - Just a thought.

Thank you in advance

thank you in advance

Mark, there’s some info. on that here that may help:


Thank you David,

That is exactly what I was looking for. I did a search of the archives and couldn’t come up with a valid link. Not sure how I missed this one. But thank you!



That link takes you to the old site where there is a wonderful Frequently Asked Questions (FAQ) section. This is not directly accessible on the new site although I believe there is a plan to link it up in the future.
If you are not familiar with that FAQ section I recommend that you browse it to see what is there. Answers to many of the frequently asked questions posted today are often found on that FAQ section. I use it regularly, as well as the archives, while working on my Jaguars.


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It does not, Mark…

The secondary throttle and housing is a Stromberg carb addition. Any modification would be relevant only with this carb set-up.

xj6 85 Sov Europe (UK/NZ)

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I didn’t think so because I didn’t remember seeing the linkage. Thank you for responding, Frank You’re a real gem around these parts! :blush:

A gem is a good thing. At least it is here.

I’m a bit late on this post but the below may help someone down the road. The info was from one of my customers a few years back, but it’s detailed with lots of good quality photos. Servicing injectors on an '86 XJ.

SD Faircloth

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Thank you! That is a great website – full of very useful information. I didn’t even think about the injector screens…

Thank you!