83 xjs cranks won’t start after weeks work and many parts

1983 XJS HE -83k miles,been sitting 2 years, owner passed away and now may be mine.
Was parked needing starter,got one and cranks but no start two weeks ago. Since then got
new fuel pump,plugs,plug wires,and coil. Got a poor yellow spark. Added additional engine ground strap and cleaned/verified every ground point on entire car.
Also put in new pulse generator,new ignition amp module ,repaired dreaded white coax to EFI.
STILL CRANKS BUT NO START. Tried starter fluid in intakes but nothing. I can’t understand how with 12+ volts at coil and starter fluid,nothing happens ! I must be missing something so any suggestions will be appreciated.
THERE IS NO SUCH THING AS DUMB QUESTIONS OR DUMB ANSWERS SO SAY IT

The initial earth connection in boot it often missed when revamping a stored car. Undo the bolts a scrape the surfaces etc clean and reassemble with toothed washer. Might be your problem.

Thank you will recheck it

Do you hear the injectors clicking?
When I did my renovation and the car sat for a year and a half, all the injectors where stuck.

Also check your distributor and centrifugal advance that will be most probably stuck as well.

Cannot get injectors to click turning to full throttle,plus I suspect one is stuck open due to wet cylinder Guess I better remove them and test. Distributor felt ok when I put new pulse generator in. Thanks for comments

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Ok, Verify the timing chain is turning. If you have spark and starter fluid, she should have at least made a noise. Also, a weak spark at atmosphere is no spark under compression.

My 84 had the same problem, it turned out to be the injector resister pack was unintentionally disconected, but I had destroyed the diodes in the ecu by trying to start it.

Yes yes! Verify and tell us if it’s longer than it should be. Two years in the garage make things grow with simple turn of the switch…

Why people are thinking that in metal-to-metal assembly - the starter motor will clear the rust away fir them?

I have been going through same issues on my 87 xjsc.
3 reputable shops couldn’t diagnose. Probably wiring has break in loom somewhere you won’t find it unless you unravel 3 miles of wiring throughout car. I have given up and am selling as parts car. The reality is a poor design is now decades old in the real world and time has caught up to most of these cars by now.

I had the same issue, i had a spark at the coil, the injectors fired, fuel at the rail. It all seem right but it wouldn’t even cough.
I removed the fuel rail (it’s quite easy), moved the aircon pump (just 4 bolts), removed the cruise contr bellows (another two bolts), removed the throttle sensor tower (4 bolts), it took a couple of hours to strip down the stuff but i then had acess to the valley so i changed out the plugs (first change in over 20 years).
I checked the injectors signal with a home made noid lamp (just a 12v G4 bulb with wire soldered on).
I put a clear bit of hose on to the outlet from B side fuel pressure regulator straight to the fuel filler to let me see that there was good flow of fuel.
Checked the spark at the end of the plug lead.
Checked the injectors on the bench using a 12 dc supply (carefull of the fuel and spark combination)

When i found no issue i put at all back together and the damn thing fired up happily (i still don’t know why it didn’t run, possibly fouled plugs).