I recently acquired a 1996 XJS 4.0L convertible with just 50k original miles- nice car as you can imagine. It had been sitting for a while in a garage unused and had run perhaps once in the last year. I've just begun tinkering with it and haven't even yet let it warm up before doing some maintenance work.

One thing I noticed immediately was a check engine light staying on and there is only one stored trouble code- P1316. The description on my scanner is pretty vague. What I found online is that this is a non-specific ignition miss. Where to begin???

The fuel is not that old- smells ok. Car has been inside so not rained on so unlikely to have water in the tank.

I think it's odd that the code would be stored so soon after start up- not even warm enough to get into closed loop....

Thoughts?

 

Once a code is stored, its stored until x amount of starts, I believe, assuming the trigger only occurred once time.


P1316 is probably a signal that the spark plugs or coils need to be replaced? Did it idle ok?


A miss can be caused by all sorts of things. Vacuum leak, EGR going bad, etc.

 

As Vee has said, misfire could be caused by a number of things. Jaguar quote the following possible causes for a P1316:

Fuel contaminated
Fuel injector(s) blocked or leaking
Ignition secondary circuit breakdown
(coils, spark plugs)
Fuel pressure low
Cylinder compression low
Broken valve spring(s)
CKPS circuit fault (CKPS DTCs also flagged)
Fuel injector(s) circuit fault(s)
(Injector DTCs also flagged)
Ignition coil primary circuit fault(s)
(Ignition coil DTCs also flagged)

After a long lay-up, it's perhaps not unusual to throw such a code. I would run the car up to temp, go for a run, reset the code and see if it comes back. Quite possible that you'll not see it again.

Good luck

Paul