What have i done now?
pretty sure something moved or is blocking needle movement..... i followed the instructions on Andrews website for tach modification, soldered in a 330 ohm resistor, (i think thats the size, was months ago when i couldnt get into garage to work on actual car) and tach seems to be calibrated pretty well, as the scan software i am using says im idling at 750, and thats about where tach is sitting, until rev it, engine runs fine and will scream if i give it gas, however tach stops at 3000, like its pegged type stop, not a fluctuation in 3000 area... guess i need to open it back up and see what i did.. anyone got any insight as to what i may have messed up???

 

recalibrate: (from the Jaguar Specialties site),

XJ6 74-87
Recalibration of the XJ6 tach is also pretty simple. Remove the tach from the dash per the service manual. After removal, the front bezel and glass can be removed by twisting relative to the case itself. From the rear, remove the screws holding the tach internals to the tach case, and remove the internals. Locate either one of the 2 wires leading to the movement itself. Cut one in a convenient spot and solder in a 330 Ohm resistor between the halves. Secure the new wire/resistor combo, reassemble the tach, and reinstall in the car. Total cost in parts- about $1.

 

Was just the resistor, had solderednitnin such a way that thenbacknside tail of the needle was hitting it .. all sorted

 

Perfect ! A simple solution. Far better than the more complex suggestion I had in mind.

But,just as a curiosity and/or information for the archives, I ask did you connect the tach via the PCM or direct to the ignition module ? My Johnscars kit suggested the latter and that is how I did it
I altered my after market harness to do that. . So far just fine!!

My similar LT1 has a cold idle at about 750 and then drops to the warm idle at 500.

Kudos on great progress. Feels great, huh!!!!

Carl

 

I tied tach in with the blue connector inside the car, pin d comes straight from pcm, i used shbox.com.and lt1swap.com for all my wiring, only thing its vague about are the things I screwed up. Lol for example the alternator wire says to guage, so i disconnected jag wire and hooked up gm one however it should have said to add to existing.. stuff like that... most of the swap sites assume its going into another gm vehicle....

Latezt issue seems.to be in vss circuit, i simply have the speedo hooked direct to the pcm speedo output whichninread would basically gice me a.way off speedo until i get it calibrated.. however im.getting a code 97 whichniant the css, the the pcm.vss output. Got more.reading to do, this may be another issue of.my.own doing.. found a site that says i may need.to terminate that wire with a resistor to get rid of the code...

Rack leak was my doing, as i was undoing everything i realized i had only finger tightened the pressure line. Doh!!!!!

Think im.done for the day, time to start drinking!!

 

I am a bit fuzzy as to the VSS. But my Johnscar kit included a dip switch box sourced from Dakota digital. That is where I have it. it only partly works. My mistake. speedo error. That can be fixed. I have the part and the instructions. but, no longer able to do all that stuff.
It is the jag speedos need for pulses and the PCM's providing them that are at issue

Why the VSS and the PCM have an issue in your car is a mystery. Each GM and pulse matched??
It runs, a great thing!!!! Other stuff, so....

Carl

 

Yeah from what I.have read, the jag needs 8000 pulses per mile and. Gm pcm.only putting out 4000, so my understanding was speed would read as just abiut double.. but i get nothing, think i might reach out to Andrew and see if his calibration item fixes the need for a 1k ohm resistor from a 12 volt source tied to speedo line....