Okay just got my '85 XJ6. everything was in working order for the first few days. There has been a couple of things that have cropped up.

#1.) The brake lights don't come on unless the lights are on. The brake lights stay on full time though. Whether the pedal is pressed or not. No brake lights at all when when lights are off.

#2.) The reverse lights work, then they don't. They will work on the first start up of the day. After that no reverse lights until she sits for a day then they work again, but only on the initial power up and reverse selection.

*** All other lights are in working order, headlights, running lights, interior, dash, etc...... ***

#3.) Trip computer went nuts! Was working when I first bought the car, now its got all kinds of crazy readings and you can't select anything on it. Is there a reset other than the button on the front?

There are a few more little things that have me raising an eyebrow, but I am sorting through those. Any inputs would be appreciated.

 

have you tried an exorcist?

 

LMAO!!!!!!!!!! THAT IS A GREAT IDEA!!!!!!!!!!!!!!!!!!!

I have a Catholic Chirch here in the area and I also know a Zuni Shaman in New Mexico I could call. I'll try the standard volt meter reading , wrench turning, beat head against the wall method first though.

 

1) My gut feeling....could be wrong....is that you have a grounding problem somewhere. Clean every ground you can find, starting with the battery cable and the main ground under the car, right side, about where the trans and engine come together. There are lamp grounds on either side of the radiator opening, in the trunk near the tail lamps, among others.

2) Th reverse lamp switch on an '85 should be at on the left side of the trans at the elector shaft stub. Four wires, you'll see it. It probable needs adjusting. Loosen the hold down screw so the switch can pivot in an arc for adjusting. If the hole for the hold down screw isn't slotted to allow for adjustment you have to remove the switch and elongate the hole. Anyhow...put the gearshift in "R" and with the key "on" rotate the switch until the reverse lights come on. With a little experimenting you'll find the sweet spot.

3) Possibly related to the (suspected) ground issue in #1 but sometimes just removing and re-seating the connector restores proper operation. The T/C pulls straight out of the panel. Just get your fingernails under the edges and wriggle it out.

A voltage drop can also be the culprit with a wonky T/C (or speedo). Check/clean/tighten the "+" junction posts on the firewall. There's one just inboard and slighty below the battery and another inboard and slightly below the brake booster

Post back if none of the above hlep

Cheers
DD

 

Doug,

Thanks for inputs. I will look into the grounding starps/points today when it dries up a bit. It's a little wet here and my bay at my shop is being used. The grounding makes a lot of sense. I'll post if it works, if not I am calling the excorsist!

 

Doug,

YOU ARE THE MAN!!!!!!!!!!!!!!!!!!!!!!!!!!!

I didn't even get a chance to check the grounding strap points. I reset the Trip Comp while I was sitting in the car waiting for it to warm up. I pulled the T/C out and reseated the plugs and BAM! T/c works, brake lights work and reverse lights work. WHY??? I don't know? I did have to adjust the brake light switch for it to work properly. Overall no problems.

Everything is now working!

Thank You Doug and Jaguar Forums!!!!!!!!!

 

By the way, WHat is the spark plug gap that is optimum on these motors for a stock coil? The book says .035. If that is correct, mine were way off when I pulled the plugs today. I am using a Jacobs coil that recommends .005 over stock. I set them at .040 and the car seems to be doing great! I did have one plug that was a bit fouled compared to the others, sticky injector or crappy wire? I am leaning towards a crappy wire, the wires look dated after close inspection.

NO, I DIDN'T GIVE HER THE TRADITIONAL TUNE UP WHEN I BOUGHT HER. IT WAS SUPPOSEDLY DONE BEFORE I BOUGHT THE CAR AND APPEARED AS SUCH UNTIL I REALLY LOOKED AT THE WIRES TODAY. THEY WERE CLEANED TO LOOK NEW/NEWER. SO I AM SURE SHE NEEDS WIRES. CAP AND ROTOR ACTUALLY LOOK NEW, EVEN INSIDE.

I AM SOURCING WIRES AS WE SPEAK.

Sorry for Yelling!!!!!!!

The Jacobs Ford 4.9/300 wires I have are dedicated to the turbo build I am involved in and I wasn't going to neglect that project. It's like robbing Peter to pay Paul when you do that.

 

I glad that everything sorted itself out so easily but....

Do yourself a big favor and spend and afternoon cleaning every ground and electrical connector you can put your hands on, especially those exposed to the elements. Clean all fuse clips and fuse end caps as well. Repeat in 15 years or so :-)

I can all but promise that the effort to do this will pay off in the future. A great many of the Jaguar/Lucas electrical horror stories come down to dirty/loose connections and grounds.

Cheers
DD

PS- Yes, .035" is the official spec on the plug gap

 

Doug,

Thanks again for the help AND not blasting me for yelling at everyone that reads the post.


David