Hello, I recently bought the most beautiful x300 3.2
straight six, that you will ever see in your life, its a
basic executive model, year 1997 with only 43000 miles, the
thing is that when I first start her up, she revs to 1500
rpm for about two seconds and during this time there is a
(not exactly unhealthy sounding) rattle from the engine. I
is not a tinny or metel to metal rattle. All subsequent
start ups when warm do not rev up to 1500 and there is no
initial rattle. The throttle cable does have an adequate
amount of slack. Any ideas anyone? thanks–
mike-xj40
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In reply to a message from Mike-xj40 sent Sat 25 Jul 2009:
I forgot to say that the rattle does definately seem to be
of the timing chain variety. (cant find how to edit my
original message)–
mike-xj40
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In reply to a message from Mike-xj40 sent Sat 25 Jul 2009:
and also I would like to add that I am more concerned about
the fact that the engine revs so highly on start up, I dont
think that the rattle would be there if there was not this
short time oof high revs before the tensioner is working
properly (is the tensioner oil pressure activated) If
anybody knows how to stop this initial high reving, then
that’s the answer Im hopefuly looking for (and can anybody
advise how I edit a post) Ta.–
mike-xj40
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In reply to a message from Mike-x300 sent Sat 25 Jul 2009:
Mike,
The high revs at start up could be an emissions thing, fast
warm up of the catalyst perhaps.
I hope that the chain is not worn out at 40 odd kmi !
Perhaps change to the thinnest recommended oil so that
everything gets lubricated quickly at a cold start up.–
The original message included these comments:
and also I would like to add that I am more concerned about
the fact that the engine revs so highly on start up, I dont
think that the rattle would be there if there was not this
short time oof high revs before the tensioner is working
properly (is the tensioner oil pressure activated) If
anybody knows how to stop this initial high reving, then
that’s the answer Im hopefuly looking for (and can anybody
advise how I edit a post) Ta.mike-xj40
–
Dan, 2000 XJ8, 125k mi, Bay Area, California
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In reply to a message from rafferd sent Sat 25 Jul 2009:
No it does not sound like a worn cam chain, it sounds more
like the tensioner can not doing its job because it is
having to much of a demand placed on it with the revs being
to high for the first two seconds, maybee before it has had
a chance to come up to pressure if it is oil pressure
driven. I have a feeling that the problem is soely the high
revs for the first two seconds and that there is nothing
wrong with the cam chain or tensioner atall.
I could liken this case to a car that the throttle
cable was set to tight and at start up revved to high, then
the ECU takes over and brings the revs back down to spec.
again. (but my cable has adequate free play)
My problem is the highr revs at start up for 2 seconds.
Any ideas ??–
mike-xj40
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In reply to a message from Mike-x300 sent Sun 26 Jul 2009:
The IACV (idle air control valve) is a little stepper motor on the
top-side of the throttle body. When you shut down the engine, it
will fully close the pintle and then open a set amount for enough
air upon the next start. You can listen or feel the IACV and have
someone shut the engine off. It should ‘whir’ for a few seconds and
stop. It probably takes 2 seconds to react to the idle speed and
bring it down to a set parameter. The newer cam chain tensioner has
a more positive ratchet to keep it tighter until oil pressure comes
up to hold it as designed.
I have installed the new tensioners and some still ‘rattle’
slightly but not like the old ones.
bob–
The original message included these comments:
No it does not sound like a worn cam chain, it sounds more
like the tensioner can not doing its job because it is
having to much of a demand placed on it with the revs being
to high for the first two seconds, maybee before it has had
a chance to come up to pressure if it is oil pressure
driven. I have a feeling that the problem is soely the high
revs for the first two seconds and that there is nothing
wrong with the cam chain or tensioner atall.
My problem is the highr revs at start up for 2 seconds.
–
Bob Gauff Owning and Repairing Jaguars Since the Early 70’s
Decatur, TX., United States
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In reply to a message from motorcarman sent Sun 26 Jul 2009:
Thanks for the reply. Do you think that the newer type would
already be fitted to a 1997 car, or were the new type of
tensioner introduced after that year? Also is there a way of
identifying the two types so as I can see which one is on my
car. Thanks again for the reply–
mike-xj40
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In reply to a message from Mike-x300 sent Sun 26 Jul 2009:
The newer style has a cast iron housing with an arrow (install
pointing up).
bob–
The original message included these comments:
Thanks for the reply. Do you think that the newer type would
already be fitted to a 1997 car, or were the new type of
tensioner introduced after that year? Also is there a way of
identifying the two types so as I can see which one is on my
car. Thanks again for the reply
–
Bob Gauff Owning and Repairing Jaguars Since the Early 70’s
Decatur, TX., United States
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In reply to a message from Mike-xj40 sent Sat 25 Jul 2009:
My 95 rattled on start at 121k - put in new tensioner at 123k. Now
at 164k rattle on start up returns occasionally for 2 secs esp if
engine hot, ambient temp hot, or car parked on hill before start.
Oil used 10W 40 semi-synth.
Also high revs on mine for 2 secs - thought this was a feature of
extra fuelling designed in for easy starting ( in place of choke)
Have become so used to it for 6 years hardly notice it now.–
The original message included these comments:
thing is that when I first start her up, she revs to 1500
rpm for about two seconds and during this time there is a
(not exactly unhealthy sounding) rattle from the engine. I
–
Ant
Kent, United Kingdom
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In reply to a message from Ant '95 3.2 sent Mon 27 Jul 2009:
I must see if there is a way to switch off or reduce the
extra fueling, its that racing engine at the very time that
theres no oil anywhere that worries me, its not good design
(unless you live in a cold country)–
mike-xj40
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In reply to a message from Mike-x300 sent Tue 28 Jul 2009:
I have had the same concern on my 4.0. I don’t like the way it
revs on starting especially when cold. Some listers on here told
me it might help to turn the key and let it go through the ‘‘system
check’’ entirely before cranking the engine. Of course, being an
old timer I never did this due to the old points ignition systems
possibly burning the points, but I do it now, and it might help or
maybe psychologically help. Also, another thing many people might
chuckle at, I use STP Oil treatment with my 5W-30 oil. The idea is
that it coats engine parts so start ups are not so injurious to the
metal on metal contacts.–
The original message included these comments:
I must see if there is a way to switch off or reduce the
extra fueling, its that racing engine at the very time that
theres no oil anywhere that worries me, its not good design
mike-xj40
–
Jim Legge '96 LR Disco '01 Jag X308
Washington, DC, United States
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In reply to a message from James Legge sent Tue 28 Jul 2009:
thanks, I will try letting the computer boot up fully before
starting and see if this makes a difference. I also use an
oil additive called active8 in my motorcycle so I think i
will give the jag a dose also, it is very expensive but good–
mike-xj40
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