[xj-s] what is considered normal gas milage for a 5.3 v-12

XJ-S
21

Jerry Peck wrote:

Reading in Kirby’s book, and I see a location given for UK cars, but
what is ‘‘underscuttle’’?

That’s under the dash – I think.

Where on US left hand drive cars?

It doesn’t exist on US left hand drive cars. US-spec cars have a 45-
second timer that gets the cats lit off. The horrible 15-minute
timer is only on UK-spec cars.

– Kirbert

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22

Hi Jerry,

Your U.S. spec 83 H.E. does NOT have either a thermotime switch or any
other 15-minute timer.

Several things to do to improve gas mileage:

(1) replace O2 sensors if >50k miles on them (with 3-wire if you still
have original 1-wire);
(2) clean & lube distributor if this has not been done per the book,
and set timing @ 18 degrees BTDC @ 3,000 RPM with vac advance hose
removed & plugged; also make sure you get ~ 0 BTDC @ idle (750 RPM)
with vac hose still removed, and then ~ 16 degrees BTDC at idle when
you attach vacuum hose. The latter two tests confirm that the vacuum
advance and centrifugal advance are working properly.
(3) run some injector cleaner through the tank, such as BG44K.
(4) check/replace your air cleaner elements.
(5) change the plugs if that hasn’t been done in 30k miles.

George Balthrop, Clifton, VA USA
85 & 89 XJ-S Coupes; 89 XJ40 VDP-----Original Message-----
From: Jerry Peck jerrypeck@cfl.rr.com

Kirbert,

Still do not know where it is, cannot find it.

Stumped.

Reading in Kirby’s book, and I see a location given for UK cars,
but what is ‘‘underscuttle’’?

Where on US left hand drive cars?

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23

In reply to a message from gbalthropxjs@aol.com sent Thu 19 Mar 2009:

George,

Thank you.

Now I know why I have never been able to find that dreaded 15
minute timer - because it is not installed! Cool!

I also now have a list of things to start checking as time permits.–
Jerry Peck, 83XJS/past-54XK140,54MKVII,59MK,60MKII,67E,72XJ6
Ormond Beach, FL, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
–Support Jag-lovers - Donate at http://www.jag-lovers.org/donate04.php –

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