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That's terrific compression for an engine of that age!
You can replace the filter baskets in the injectors with the proper Bosch kits. I think in the photo albums at the link in my signature there may be some photos of a puller I made to remove the old filters. I may also have photos showing how I clean injectors with Techron Concentrate Plus Fuel Injector Cleaner under 20 psi of pressure while activating the injector solenoid repeatedly. There are now inexpensive fuel injector actuators that make this easy. I have something like this and it works great:
I think I remember that you've checked the Fuel Pressure Regulator vacuum fitting for the presence of wet fuel. Have you figured out how to test the fuel pressure? The XJ40 requires some metric fittings to tap into the fuel lines nondestructively. Bryan N of the Jag-Lovers forum came up with this:
That's terrific compression for an engine of that age!
You can replace the filter baskets in the injectors with the proper Bosch kits. I think in the photo albums at the link in my signature there may be some photos of a puller I made to remove the old filters. I may also have photos showing how I clean injectors with Techron Concentrate Plus Fuel Injector Cleaner under 20 psi of pressure while activating the injector solenoid repeatedly. There are now inexpensive fuel injector actuators that make this easy. I have something like this and it works great:
Ah yeah I have one of those. I planned on doing the filter baskets as well, I made up a little thing for getting them out back when I rebuilt my XJS fuel rail.
I figure an hour or two in the ultrasonic cleaner, plus some solvent or injector cleaner being blown though while actuating, and we'll see if it makes a difference. I'm betting no, but we'll have to wait and see, most likely sometime next week before I get around to it.
As for testing the fuel pressure, I just cut off the crimped collar at the end of the feed line to the rail, and used my gauge with two barb fittings connected to the old hose on one side, and a new piece of fuel injection hose on the other. Same thing I did when refurbing my XJS rail, just slid the hose back over the barbs, and secured with a fuel injection clamp instead of the old crimped collar
Last edited by BuckleSpring; Jul 2, 2025 at 08:54 PM.
While I await the injector kit, I pulled out the rail and injectors to get started on cleaning.
The inside of the rail looked fine, no debris came out while flushing it. Smelled like varnish though.
The injectors were interesting. The tips of the actual injector looked clean, but the pintle caps were all covered in a thick layer of sticky varnish. I took each injector, hooked up 2 feet of fuel line to each, connected the injector to my little pulse machine, filled the line with some strong cleaner (acetone, toluene, etc), and flushed each of them with an air hose connected to the line.
3 of the 6 immediately had a nice spray pattern. The other 3.... they weren't blocked, but were just shooting a stream, not a nice atomization pattern. I flushed each injector with my mixture 3-4 times and they now all have good clean spray patterns.
I was going to toss them back in the car as-is to test, but fell asleep with them in the ultrasonic cleaner... and forgot to take the o-rings off before I put them in there with my industrial cleaner. They didn't like that as you can imagine, the o-rings didn't survive overnight in the tank. The kit is on the way, new o-rings, pintle caps, etc. I'll have an update probably Thursday, I believe that's when they'll be delivered.
It was a lot of fun getting the banjo bolt aligned to thread back in.
Unfortunately, it would seem that disturbing the hardline out of the filter has caused it to crack somewhere....
It's the one with the banjo fitting on the end, that goes up and over the filter I think. Going to try and find the part number and order one I guess, doesn't seem like a lot of fun to replace, so I may take use of my friend's lift.
@Don B You might have the information I'm looking for.
I'm looking for the Part Number for the fuel line that's broken on my car. It's the one that connects to the outlet side of the fuel filter w/ the banjo fitting. I checked the Jaguar Heritage parts diagrams but didn't see anything that really looked similar. The one diagram I found that kind of made sense returned no information when searching for the part number on Google. I can't find any google images or ebay listings for the line either
If I can't find one, I may have to order a same-size banjo fitting with a barb adapter on the side and replace the line with rubber fuel injection hose.
@Don B You might have the information I'm looking for.
I'm looking for the Part Number for the fuel line that's broken on my car. It's the one that connects to the outlet side of the fuel filter w/ the banjo fitting. I checked the Jaguar Heritage parts diagrams but didn't see anything that really looked similar. The one diagram I found that kind of made sense returned no information when searching for the part number on Google. I can't find any google images or ebay listings for the line either
If I can't find one, I may have to order a same-size banjo fitting with a barb adapter on the side and replace the line with rubber fuel injection hose.
Hi BuckleSpring,
Sorry for the delay in responding. We've had a crazy month between work and family time. Have you checked:
Jaguar shows all the fuel lines are No Longer Available new, so your best bet will be to find a good used line or do as you proposed and fabricate a replacement line.
Jaguar shows all the fuel lines are No Longer Available new, so your best bet will be to find a good used line or do as you proposed and fabricate a replacement line.
Cheers,
Don
You're fine, I've been taking some time to take care of stuff in my XJS, but that's an entirely different debacle
I looked at the diagrams and didn't really see anything that looked similar. I'm going to see about getting it on my friends lift and investigate where exactly the issue is and if I can easily cut/flare/union/etc it.
I was able to get the XJ40 back up and running w/ a 12mm banjo fitting. After letting it idle for a minute or so to let the rebuilt injectors clear out... It definitely runs a lot better now.
Doesn't stumble or fall on its face when giving sudden throttle inputs or putting it under load... It was even able to drive up the ramps and onto my trailer without a hitch.
Bled the brakes while I had it on the lift. Lots of not-good fluid came out, as you can imagine, but after that... Seems to be improved on the brake feel front, ABS seems to be working now as well.
Honestly it still seems a bit... down on power, not sure as I've never had an XJ40 before. Engine is running perfectly though, might properly service the transmission before chasing that down.
Definitely in need of a trans mount rebuilt, and rear upper shock/strut mounts, and the water pump seems to have started leaking out of the shaft seal.... but at least it seems to be running properly now.
Took it on its first true maiden voyage, just a couple of miles and back, as far as I was comfortable with the water pump while I'm waiting for the new one to be delivered.
Actually drove shockingly well all things considered, aside from the transmission.
Seems to be stuck in 2nd or 3rd, but no transmission light. It did throw a FF14, so I'll swap the sensor with one from my XJS parts bin and see if anything changes, although I'm not sure if a coolant temp sensor circuit is enough to trigger limp mode on an XJ40.
For anyone curious, my TCM light was due to water getting into the TCM from... somewhere. I resealed the harness grommet under the battery tray and checked my door seals and it was still wet, so who knows. Tried cleaning the TCM to bring it back to life, and didn't have any luck. Bought a new one, coated the boards in conformal coating, and ran a bead of RTV on the case halves when i put it back together just as a precaution while I figure out where the water intrusion is coming from. Still get an occasional Transmission Fault light when switching between reverse and drive, but I think that's just a minor adjustment issue from when I had the rotary switch off for cleaning.
Water pump was replaced with a new one, was extremely straightforward after the smog pump and all relevant hoses and brackets went in the bin.
FF14 was a coolant temp sensor that was dropping out at operating temp, easily fixed.
Car drives shockingly well now, all things considered. 3D printed some new rear shock bushings which quieted up the suspension and makes it actually drivable.
Thanks for letting us know, it always helps to have solutions listed to problems, Just to throw it out there (ive been dealing with leaks a bit this year as well) have you checked at the bottom of your windshield and under the cowl trim panel?
Also, can you brief us on 3-d printing parts? its something many, if not all of us, could benefit knowing more about.
Thanks for letting us know, it always helps to have solutions listed to problems, Just to throw it out there (ive been dealing with leaks a bit this year as well) have you checked at the bottom of your windshield and under the cowl trim panel?
Also, can you brief us on 3-d printing parts? its something many, if not all of us, could benefit knowing more about.
What should I be looking for under the cowl panel?
As for the 3D printing, I printed new bushings for the rear upper shock spacer donuts. I just bought the tophat bushing (CBC2933) because they were cheap and readily available. The spacers seemed to only be available through a couple of places (SNG and maybe Moss) and were bewilderingly expensive for a couple of pieces of foam... so I 3D printeed new ones out of TPU (polyurethane). I put the files on Thingiverse and Printables if you wanted to have a look, shouldn't be hard to find.
Last edited by BuckleSpring; Dec 24, 2025 at 07:45 PM.
Im trying to remember whats under the panel exactly. Its an excellent place for dirt to collect and cause rot. It can also plug up the drains in the heater box and make the rug wet. Im not sure if any of that would be in the "right place" to get into the TCM, but the panel isnt hard to remove so its a relatively easy thing.
