Re: XJ6 S3 (bad) behaviour at kickdown

[Mike Morrin <mikem@southern.co.nz>]

John Ratcliff wrote:
> 
> Hello fellow Jag lovers,
> 
> My 86 XJ6 S3 exhibits a bizarre behaviour. It can be reproduced
> pretty much at will. When driving at a stable ~90km/h in 3rd, slamming
> the loud pedal down causes the 'box to downshift in 2nd (normal), the engine
> picks up about 200 rpm and then remains stuck at ~3'700rpm (not normal). It
> won't pick up more rpms and it runs coarsely.

Although not quite the same symptoms, I once had to fix an SIII which
would not pick up from idle when in gear, but would in nuetral.  In gear
the engine speed would pick up to about 800RPM and then just run rough
and get no faster (no matter how much loud pedal was applied).  If in
neutral the engine was revved to about 1500 rpm and then dropped into D,
the car would take off with some wheelspin and drive normally at any
RPM.

For some reason, the owner was not happy to drive the car like that.

It turned out to be a faulty ignition module.  For some reason, under
some running conditions the dwell angle was dropping to zero, thus no
spark and rather rough running at fixed speed.  This was easily observed
by putting a standard dwell meter on the coil.  If I remember correctly,
the indicated dwell on these systems should be 90% or higher.

good luck,

Mike Morrin.

---

References:

• XJ6 S3 (bad) behaviour at kickdown
• From: John Ratcliff <jratcliff@atlantica.access.ch>

---

• Prev by Date: Information needed on XJ6 valve seals
• Next by Date: [Jag Engine General] Painting Cam Covers
• Prev by thread: XJ6 S3 (bad) behaviour at kickdown
• Next by thread: Just Thinkin...
• Index(es):
  • Main
  • Thread