I am trying to finish up the '72 Jaguar XJ and it is fighting me to the end..

Replaced the LT1 FPR (fuel pressure regulator) today and all is well and it drives properly again.

The Jaguar oil sender for the oil light was flaky and I replaced it today. Discharging was happening before the new sender was
installed.

Now it quit charging, 11.8V (meter) when idling and the gauge shows the same discharge... did nothing to the
alternator or electrical circuits... has a near new (under 1000 miles) Power Master 140 amp alternator that has worked
perfectly for several years now.

Without proper voltage the turn signals are slow, it starts to have trouble firing the injectors at higher speeds and the sun roof will
not close/open properly.

Even the lid on the LH ash tray is now "sticking" when opening and closing...

Anyone know a good Priest that makes "car calls"?

 

what was the humidity when all this happened?

 

I feel the same way...sometimes. Old car have lots of problems....reminds me of the "Joe Lucas...prince of darkness" Jokes.

But away from the supernatural for a minute...I'm currently exercising various demons from a BMW v12. It's going better than the Jaguars ever did....The parts cost dearly and once something is fixed its fixed. I can only surmise the rarer and more costly parts are of better quality. Case in point I went through 3 GM alternators from various low cost providers before I got one that worked properly. I guess this is because all of them were rebuilt off shore and I didnt want to pony up the coin for a dealer unit for use on my franken car. With the V12 Bimmer..dealer parts are sometimes the only option thus avoiding self defeating low cost, low quality part traps. With the GM stuff... Its quite a difficult dilemma, one part cost 1/3 the price and look exactly the same on the outside when compared to the dealer part.

Another thing to consider...After welding on vintage Jags and undertaking various wiring issues, I can confidently say, empirically speaking, that Jag steel is a poor conductor relative to every other car I've worked on. So run ground straps to everything.

 

Yes, I am aware and the alternator has a ground strap since it is chrome plated (mfg) and I filed away the other connection points
when installing it several years ago.

Big "red" wire is still there and in good shape and the firewall connector has been replaced, cleaned and lubed in the recent past.

Will install the small 85 amp alternator I had to use while waiting for the mfg to swap the alternator originally - under warranty. It is a original
GM unit and has always worked.

Yes, the quality of replacement parts - auto/other stuff - is very poor today. Most of the stuff is made off shore with below zero quality control.

This alternator was made in the USA... I even had them confirm it was working properly before shipping to me.. got to become friends with them
over the application of LT1 to early Jaguar. Even sent them the picture shown here of their pretty chrome unit with the ground strap shown.

 

I pretty much gave up on off-the-shelf starters and alternators. It seems that chances of getting a 'good one' are no better than 50-50 these days....and brand name on the box doesn't mean much. So many products are 'label engineered' these days you really don't know what you are buying.

So....

All my starters and alternators now go to a local rebuilder

Art's Automotive | Auto Repair Longview, WA 98632 | Longview Auto Repair Shop & Service Center

Besides regular auto repair they have their own on-site rebuilding department. I'm sure many other towns have a local rebuilder as well, and I suggest going that route. That 50-50 success rate is now 100%

Cheers
DD

 

Well, I am in the midst of starter adventures. the one on my LT1 may or may not be original GM. And, tests have been inconclusive, on and off the car.


So, I shopped at Rockauto. Several options and a widespread price range. I "cheaped" out for a new unit. turns out to be made in Malaysia!!! Looks great and almost exactly like the one I removed. It together with the rebuilt switch to relay to solenoid harness cranks fine. Seems quieter than the old, when it cranked. But, my ears are far from a good judge of noise!!!


Son says I erred. Should've gotten a rebuild.


I kept the old. I may do more checking and perhaps an autopsy.


Grounds:


You bet. Grounds via chassis are less than ideal. I have a relay rack. Alongside is a ground bus. The latter has most of the relay ground legs. Ac ouple of exceptions as now configured. It in turn is grounded to the wing wall, where the - post of the battery is grounded.


Carl

 

Had both starters checked at O'Reilly... they both passed!

Put the big 140 AMP unit back on (there is a ground wire)... confirmed the wiring and it still shows a discharge on the Jag gauge... confirmed there is only battery voltage (a little less due the many connections) on the rear posts of the Jaguar battery gauge = but close to the voltage at the battery.

But:

There is 14.3V at the big terminal/post on the alternator when running. So the alternator is charging but it is not getting to the
battery.

Bat Voltage at alternator post when off

Plug on the alternator uses Pin "L" it is battery voltage when key is ON (this plug is connector to a large cloth covered wire that goes into the
harness inside the car - colors (faded - Red (maybe Brown) with dark stripe or parts of a stripe - that is Blue or Black).

Plug on the alternator uses Pin "S" it is hot all the time with battery voltage and according to GM, "It is charge level sense line".

Battery shows the same off/on running or not... battery is fully charged at 12.8V (near new Optima).


S1 Ignition light in center of the dash between the Speedo and Tach does work with key on and when engine is running (most of the time - sometimes with the engine running the bulb goes out). Bulb is good as I exchanged it for the Brake bulb. There is battery voltage at bulb base when key is on or engine is running and no voltage when key is off

On the posts of the Jaguar battery gauge there is Bat voltage running or not.

I disconnected the power wire for the rear amps to eliminate that from the problem.

Any knowledge of the Ignition light circuit or suggestions on things to check?

 

Andrew from Jaguar Specialties was kind enough to look at a LT1 harness and inform me that there was only the post wire and one other hooked up to pin "L".

I disconnected the wire to "S" and the idiot light is out now when running and it is charging properly... confirmed with a meter and the Jag gauge.

Amazing, since that wire has been connected since 2008 and it was working properly..

I AM SO HAPPY, but do not understand why it worked that way before???