Hi all,
An update on the cat not starting.
In the end I got my local jag specialist(JagCare from Portsmouth
UK) to come out & have a look, they sorted it right away by
replacing the Coolant Temperature sensor. Yes, even though it
tested OK, 4000 ohm accross the connectors cold & infinity with one
on the connector the other on the senor body, it was still faulty,
I would guess that the wrong signal was being sent to the control
module, I think I will repeat the test with the new senor & compare
readings. I must admit I felt a bit miffed as that was the first
thing I checked, I guess we will have to treat it like the CPS
(replacement as the best test), anyway I have the cat back for
Christmas so I’m a happy bunny!!
Thanks to all who helped with advise, we had the answer just didn’t
realise it!!! Have a great Christmas all.
I read somewhere, perhaps Kirby’s Book or some of Roger Bywater’s
writings at the AJ6 Web site, that intermittent failure of the
coolant temperature sensor has been reported.
Ed Sowell
76 XJ-S http://www.efsowell.us/ed/myJag.html
Yes, even though it
tested OK, 4000 ohm accross the connectors cold & infinity with one
on the connector the other on the senor body, it was still faulty,
I would guess that the wrong signal was being sent to the control
module, I think I will repeat the test with the new senor & compare
readings.
I read somewhere, perhaps Kirby’s Book or some of Roger Bywater’s
writings at the AJ6 Web site, that intermittent failure of the
coolant temperature sensor has been reported.
Well, it’s been reported on-list several times. I recall from a few years
back, one lister had made a trip up from the San Diego area to San
Francisco for an informal gathering of Jag-Lovers members, and he had fits
with his car the entire trip - he even stopped by XK’s (in San Luis Obispo)
on the trip up to get a replacement fuel pump because that’s what it seemed
like, and that didn’t cure it. It wasn’t until after he’d returned home
that he finally diagnosed the problem.
From what I’ve seen here, they’re more likely to go intermittent when the
engine warms up and things are subject to thermal expansion. In that case,
it would seem like an ignition fault or possibly fuel starvation. If it
goes open while cold, then you have a no-start that should resemble
absolutely no petrol or absolutely no spark (there won’t be so much as a
sputter from the engine, unlike a marginal ignition or fuel where it’ll at
least periodically start to catch).
On my website, I’ve got a simple writeup on a small gizmo you can assemble
and toss in your in-car toolbox to save you from the debilitating effects
of a CPS failure should it ever happen to you, though a proper value
resistor jammed into the sensor socket would suffice. The gizmo I made is
a 2 value switch - one for cold and one for hot, so you can let the engine
warm up with a reasonable fuel mixture, then switch it to the hot setting
and drive.
In the end I got my local jag specialist(JagCare from Portsmouth
UK) to come out & have a look, they sorted it right away by
replacing the Coolant Temperature sensor.
When you get a chance, you might try checking the “Sounds Jaguars Make”
link on my site (which I’ve not added any new sounds to lately, but have
plans to). The crank sound of a bad CPS is in there.
What may be happening is with all the testing and on /off with the
connector the contacts might have gotten a better connection. The FI
type plug deteriorates allowing the plugs inside to push back. So your
old sender might have been okay, just not getting the signal to the ECU
properly.
Steven
J.C wrote:
Hi all,
An update on the cat not starting.
In the end I got my local jag specialist(JagCare from Portsmouth
UK) to come out & have a look, they sorted it right away by
replacing the Coolant Temperature sensor. Yes, even though it
tested OK, 4000 ohm accross the connectors cold & infinity with one
on the connector the other on the senor body, it was still faulty,
I would guess that the wrong signal was being sent to the control
module, I think I will repeat the test with the new senor & compare
readings. I must admit I felt a bit miffed as that was the first
thing I checked, I guess we will have to treat it like the CPS
(replacement as the best test), anyway I have the cat back for
Christmas so I’m a happy bunny!!
Thanks to all who helped with advise, we had the answer just didn’t
realise it!!! Have a great Christmas all.