Ooops, I meant to say sender, not gauge.
Been a hard day, and not yet beer o’clock
Looks like you need a new gauge. The original senders fitted to
the XJS were known to go a bit dolally after a while, exhibiting
the symptoms you have described.
Jaguar introduced a modified sender in the mid 90’s, which has a
resister fitted. However, the new sender is not really a pressure
sender, it just detects that there is some pressure, and sends a
signal to the gauge, which I believe sits a mid scale.
The old type sensors are still available from parts suppliers.
Its a bitch of a job getting it out of the straight 6 engine, but
is doable with a crowsfoot spanner.
The problem may be to do with electrical noise, When I got my speedo
alteration done(with the supra conversion) the speedo would jump all
over the place inconsistently. It was fixed with a small capacitor fixed
in series with the signal line I think. See if you can get someone to
put a trace on the gauge line to see if I is a noise problem.
(The obvious alternative is to check with a known sender).
Regards Kevin '85 xjs
The round oil pressure gauge on my 93 exhibits a jumpy behavior,
particularly when at idle. Once up to speed, the needle tends to be more
stable, although it may still jump around once in a while. On two other
cars (both 93s), I’ve noticed the same behavior on one, while the other
car had normal gauge operation (a slowly rising or falling needle as a
function of engine rpm, but stable).
Has anyone with a round gauge seen a similar behavior? If corrected,
what was the solution…a new sender or a new gauge? (or something else