Hi guys,
I would really appreciate some help with an issue. Sometimes when I
start Jag from cold and also occasionally when at normal running
temperature the engine idle oscillates between 900 and 1500 rpm,
watching the tacho it just goes up and down. As soon as it gets to
1500 it immediately drops back to 900 then immediately back up
again. Tonight I did a test and just let it hunt up and down and
after about 6 fluctuations it sat at 1500 then slowly reduced to
800 and was constant. It is not a huge problem except that
sometimes when braking I am braking against the engine which
obviously wastes petrol & brakes. Otherwise the engine runs
beautifully I did a head gasket 2000 km ago which included having
the head professionally redone and 12 new exhaust valves. The guy
that looks after my Jag believes the computer is receiving
conflicting signals. He measured the air flow in the inlet and it
is recorded at 10mm of mercury and in Canberra at our altitude the
normal is 18mm with 15 16 or 17 being acceptable. Anu thoughts
would be appreciated,
Trev.
I have spent more than $500 and am no further on…–
topendtrev
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[See also section 10.5 for TB cleaning]–
The original message included these comments:
I would really appreciate some help with an issue. Sometimes when I
start Jag from cold and also occasionally when at normal running
temperature the engine idle oscillates between 900 and 1500 rpm,
watching the tacho it just goes up and down. As soon as it gets to
1500 it immediately drops back to 900 then immediately back up
Visit the Jag Lovers homepage at http://www.jag-lovers.org for exciting services and resources including Photo Albums, Event Diary / Calendar, On Line Books and more !
In reply to a message from Bryan N sent Mon 20 Jul 2009:
When mine started doing this, my tame jagman straight away
said ‘‘Dirty throttle body.’’ Cleaned it, re-assembled it,
some slight adjustment on idling screw [? I didn’t ask, I’m
guessing]. Result? No more hunting.–
JagFab,1989MY JaguarSport XJR 3.6 (RHD)
London, United Kingdom
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In reply to a message from topendtrev sent Mon 20 Jul 2009:
When this occured with my 89 the first question my jagman asked
was ‘‘when did you last do the throttle body’’. he did it and the
problem was solved, also there was a noticable increase in power.
John–
John. Walsh. Purrrrr 89 vdp
bowmanville ontario, Canada
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In reply to a message from h s law sent Mon 20 Jul 2009:
I also did the throttle body. No difference. I let it idels now
until it setles down.–
Alan (XJ40 3.6L 1987/8)
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In reply to a message from Alan4d sent Mon 20 Jul 2009:
Sorry Guys. I can spell, but my email system picks up typos and of
course this does not, and I got lazy!–
Alan (XJ40 3.6L 1987/8)
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In reply to a message from h s law sent Mon 20 Jul 2009:
hi guys.
just reading this with interest and also my haynes manual on the
procedure for removal/cleaning the throttle body.
just wondering though.
why is required to drain the radiator and can it be avoided?
me and coolant systems dont get along very well and I was forever
getting air locks in my last car!!!
regards, mark.–
The original message included these comments:
was ‘‘when did you last do the throttle body’’. he did it and the
problem was solved, also there was a noticable increase in power.
Visit the Jag Lovers homepage at http://www.jag-lovers.org for exciting services and resources including Photo Albums, Event Diary / Calendar, On Line Books and more !
just reading this with interest and also my haynes manual on the
procedure for removal/cleaning the throttle body.
just wondering though.
why is required to drain the radiator and can it be avoided?
Visit the Jag Lovers homepage at http://www.jag-lovers.org for exciting services and resources including Photo Albums, Event Diary / Calendar, On Line Books and more !
In reply to a message from Bryan N sent Mon 20 Jul 2009:
if CARLING gave advice, they d have to change their name to BRYAN!
(lol)
your a top man bryan, thanks for that, appreciate it.
i ll have a go at that soon. not that its playing up, but as they
say, prevention is better than cure .
mark.–
The original message included these comments:
Visit the Jag Lovers homepage at http://www.jag-lovers.org for exciting services and resources including Photo Albums, Event Diary / Calendar, On Line Books and more !
Visit the Jag Lovers homepage at http://www.jag-lovers.org for exciting services and resources including Photo Albums, Event Diary / Calendar, On Line Books and more !