Hello! I'm new to the forums.
I inherited a 1987 XJS, V12 Coupe HE (i'm in Ontario, Canada) from my grandfather who owned the car for about 30 years. She is in pretty good shape interior and exterior, and fairly mechanically sound. I absolutely love the heck out of the car, and I want to treat her right.

There are some issues that i'm going to address with her and I want to take a hand in it myself. I've read all of Grant's sticky notes (HE tune up and cooling system especially) but it's all greek to me right now.

I know car basics, but this Jag is a bit.... complicated.

So what's happening right now:

-She definitely has significant quiescent power draw - Resolution: There are tutorials for understanding where parasitic battery draw. Apparently the light in the trunk and the security system can be problematic. Interim resolution: I bought a NOCO genius 2 trickle charger
-Rough idle: She is idling rough, and running rich ( i can smell it)
-> More present while hot then cold
-> D: 600-625 rpm, N 775 RPM steady, R600 - 625 RPM. She searches under load (R and D), with a 25 -50 rpm range
-> She hesitates if i'm in drive and i tap the peddle (it almost stalls). However this is made worse when the battery is "low". For some reason the battery is low upon startup. The voltage on the dash display for the battery power is around 10 or 11 and slow makes its way up. She still hesitates no matter what, and it's definitely worse when the car is cold
-> She is a bit noisy on the engine, but i think it's because there is a misfire (cylinder not firing)
-> When idling in drive, she shakes a bit, but no other noises
-> I can smell she is running rich, and it stings my eyes when she idles
-> Fuel economy is in the tank (I drove her 100 km and it cost me like 30 litres)
->Before I got her, she sat for a year
Interim resolution: I added some injector cleaner and oil conditioner cleaner and ran her on the highway. Didn't help.
Long term resolution: cam shaft timing sensor (does this car have one?) Injector cleaning, mass air flow sensor check, O2 sensor check, distributor check (with a multimeter? is it possible?), spark plug replacement, check vacuum lines (she could be leaking).

My concern with this car is that everything looks crazy complicated. I'm used to driving an F150, and this engine bay scares me. Furthermore, i'm a hands on/visual kind of guy so following written instruction is tough for me (but i can literally memorize a video or remember step by step if i'm shown/do it myself once). I have the motivation and time to do the reading and learn.

As a biochemist, I take evrything in a systemic, logical manner, bit by bit. Every problem can be solved in my mind, it's just a matter of breaking it down into discrete enough pieces and putting it back together.

Anyways, if anyone wants to comment on my resolution steps I'd appreciate it. Pictures to come!
Thanks!
Darth

 

I would stop driving the car for a bit...

Get a digital volt meter or some device that can give you accurate readings of voltage and start taking measurements in different places around the car. Look for 12, 13, 14v while the car is running. The gauge on the dash is only good for so much...

Take a WHOLE day, a bit of sand paper and some electrical parts cleaner and go around the car, battery discon, and clean EVERY GROUND point, relay connection and electrical connector you can find, to the best of your ability. Don't skimp on the battery terminals and the battery ground connections in the battery area. In the same day, pull all fuses (which also may be 30yrs old) and clean the tabs or replace outright with new fuses. The XJS doesn't have many fuse compared to newer cars believe it or not and,,,, you may not like this, but just spring for a new alternator. If you do, folks here can walk you through installing it. A proper charging system makes a great difference in these cars.

For the gas (the real reason to stop driving) please let the forum know where the wiring for the fuel injectors are. Are they reachable at the top of the engine around the fuel rail, or way down in the depths of the V - the "valley" at the very top O the engine, where the distributor, cruise control and throttle stand is? 30+ years and extreme temperature recks havoc and creates shorts that lead to NO or heavy fueling. It's important.

Then, on the LHand side of the engine, (and you can search "19xx Jaguar XJS coolant temperature sensor location") you will find an important sensor with a two wire plug bolted into the thermostat housing. Replace the sensor and clean the connection.

Your idle is actually a little in the low range which might suggest you are ok with vacuum leaks... This is good.

The fuel injectors (individually) and the fuel lines are a whole other (IMPORTANT) story.

Can you take a few good photos of the engine bay with close ups of the fuel rail and fuel lines and post pictures yet?

What's the idle COLD? At first start?

When running, if you stand behind the car, the exhaust should produce a near uninterrupted smooooooth sound. If you hear ANY pops, dis-rhythm, bubbling or - how ever you describe it - the engine is misfiring and is NOT a good thing.

Believe it or not, if there are problems in any area, all is pretty easy to sort out. Just time consuming and not common knowledge. There are folks here who are WAY smarter than me about these cars that can and will get you thru anything to do with them - and it sounds like you are starting from a good place...

Just take it a bit at a time.

 

Just to restate...
there is a strong possibility the rawwww unburnt fuel is flowing and accumulating in one or both sides of the exhaust system and until you are certain that ignition and fueling systems are working properly,,,, no more driving!

Jus saying... This is an important bit

 

OK, written is all I know, too damn old for anything else, and I am not asking the kids, who still think the old man is Batshit Crazy for having so many V12 Jags in the 1st place, and topped up the fleet with the lesser engined beasts as they appeared.

The V12 is SIMPLE, and I am NOT joking, only made complicated by overthinking things. The thing is a 1954 design, so think back a tad.

1) Noisy, mmmm, not usually. The Injectors CAN be "clicky" and that is a noise. There is a danger of "clack, clack, clack", and you 100% do NOT want to be hearing that, as terminal engine is the root result.
2) Idle shakes, NO WAY, so there is an issue here, and the fuel usage you are talking has me at:
A) FPR ruptured and overfueling. FPR = Fuel Pressure Regulator, and you have 2.
B) Spark plugs are wrongly gapped, and the 2 front, one on each side, have never been replaced, as they are a PITA on a good day.
C) HT leads are just plain OLD.
D) Injector loom is shorting, its 30+ years old, and fair is fair. That will overfuel, shake, etc the engine.
3) As said, CEASE RUNNING THIS ENGINE until the fuel issue is sorted 100%, engine fires are not a good experience.

Cam angle sensor = NO GOT.
MAF, = NO GOT.
O2 = NO idea, our market, NO, yours maybe, but they will not cause this alone. They may well be toast due to the overfuleing, dunno.
Distributor test???? = it runs, the dizzy is working. Removal of the cap and checking mechanical advance for seizure, and so on, NOT a bad idea, but the fact its running, leave it for now.
Spark plugs = TOP IDEA, and ensure they are gapped at 0.025" please.

Now the best part, drink beer, soak all this in, let fear disipate, show fear to a V12, and you have lost before you start.

Read the stickies at the top, and if something is unclear, ASK, none of us bite, especially me. I have many PDF's on all sorts, and most are in the archives somewhere, but ask, and I will attach again to this thread,.

It can be fixed, and driven daily, ALL mine were and are. One is 655000kms now and untouched internally, the outside stuff, Oh Dear, that is probably 3rd or 4th replacement.

Have fun, its all we have.

 

OK I have some pictures!! To be clear, my grandfather took extremely good care of the car for 30 years.

 

Looks like a nice, well kept Jag.

A couple quick remarks:

- Those fuel hoses look original. replacing them should be put high on your list
- The cover over the cruise control bellows is upside down. It goes underneath the bellows :-)

More later

Cheers
DD

 

Agree with Doug.

I am not doubting the care that been given that car.

AGE is against any Non-metalic item under that bonnet, and that is just plain fact.

With those OE fuel hoses, I would not be starting it at all, I have been nearby a couple of fuel hose related engine fires, NOT funny at all, and they erupt in less than a heartbeat.

I understand. also, that I am a tad pushy, its the Aussie, but really, things need to be attended to, and that car will see you out, and make an awesome daily driver, if thats what you want.

The XJS is rising on the "must have" list, and good examples, like yours, are way at the top. Down here that would fetch serious $$.

 

Oh no worries, I like it straightforward.

I'm looking into replacement hoses and kits.

I came across v12performance which appears to have some packaged kits. Not sure if it's any good. shopping around for hoses, fuel lines etc. I'll be talking with the mechanic who took care of the car next week, and im looking for the service records.
I'll definitely be replacing the fuel lines

 

I'm new to car maintenance outside of regular oem replacement.
it looks pretty straightforward replacing the lines.

I design and build pilot plants in the nuclear and mining industry, and we use swagelock for cryogenic flammables.
i'm looking at the flow rates, pressures and temps, and it looks like swagelock would work easily. It would basically give you 50 years use.

 

Just want to say I love that you're keeping your grandfather's car. That must be what he wanted.

 

Thx! He's still kicking around (90+) but he wanted me to have it and take care of it. He loved the hell out of the car, and I have a lot of fond memories cleaning it, waxing it, going to car shows with him as a kid. Now I get to take care of it and I want to be able to pass it off to my son, which is why I really want to learn and make sure everything is done right.

 

Great story. And you're very fortunate to have an XJS that has been basically well kept and, judging from the pics, not hacked and butchered. This is rare, and a real "plus". I think you have a gem on your hands.

These are fabulous cars to drive and, IMO, well worth the efforts needed to keep everything up-to-snuff. Whatever effort you invest the car will repay in equal measure.

That said, and not intending to disparage the car or your grandfather for even an instant, I can pretty much promise you that there will be areas that haven't gotten the attention they need. Stuff that every old XJS needs. Those fuel hoses, for example.

More on the bright side: virtually every problem and fault you're likely to encounter has been documented over the years and the cures and resolutions known and shared. The internet support for old Jags is among the very best you'll find. In a sense it's easier to own one now than it was 20-25 years ago.

Cheers
DD

 

Thanks Doug, absolutely there will be things I need to work on, and I want to (like the fuel hoses!)

 

Not sure of your location Darth but Sandy Faircloth in Florida does really good work on the fuel injectors and hoses. I'm fortunate that he lives in the same town as me.
https://www.jaguarfuelinjectorservice.com/

 

awesome thx, i'm from ontario canada.

I might buy a spare set of injectors and store them when parts become very hard to come by

 

Whoa there on hoarding parts! There are reproductions available for next to nothing if you just want to keep it running. Enjoy doing some research, you'll find a lot of support for these cars.

Also must second Doug's comment about them being easier to own now. Back in my pre-internet MGB days I hunted down a rumoured supplier of fiddly little bits to get the carbs sorted...it took weeks. Now you usually have several vendors shipping to your door in days, all kinds of diagrams and schematics...and the best tool of all, THIS FORUM!.

 

If you google "fuel injector service thorold" you get a list and you'll quickly find someone to rebvuild and bench test your injectors. I had mine done locally for $25 each. They also had the correct hose for me.

 

Thx for the feedback! I dont know what's legit and what's not. Like, is there a master thread somewhere on good vendors in Canada/US for our cars?