My E starts great when cold. After a nice run if I stop
somewhere and let it sit the heat soak most likely percolates
the fuel in the carbs and fuel crossover. Usually when I try
to start it hot I turn the key to run to let the fuel pump
supply cooler fuel to the system, then full choke and hope
catches on the first hit. It does have a new style gear
reduction starter so it cranks well. Thanks for your comments
and ideas in advance !!–
Ralph B - '72 Ser3 V12 2+2 , Middletown, Delaware
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
In reply to a message from Ralph B sent Sun 11 Aug 2013:
Hi Ralph,
Usually difficult hot restart on the v12 is due to excess
fuel (too rich)…it takes a few cranks to pump out the rich
mixture & get things back to normal.
On mine I found an improvement by setting the float heights
at the minimum spec (max dimension when set upside dowm). I
believe this reduces the float chamber �verflow’caused by
heatsoak on a hot shutdown & therefore reduces the rich
mixture problem.
Your situation may be different: you say you use choke on a
hot start and it starts??
Running the fuel pump will exchange the fuel in the
crossover, but not the carbs themselves–
Dave S3E,RR SS, BMW’02,Tr4a,Elise, http://www.xketype.com
Georgetown, Penang, Malaysia
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
In reply to a message from Ralph B sent Sun 11 Aug 2013:
Difficult hot start re-starts was the first sign of my opus going.
Keep a bottle of air duster in the car and spray it on the opus
when it is hot…see if that helps restart.–
The original message included these comments:
My E starts great when cold. After a nice run if I stop
somewhere and let it sit the heat soak most likely percolates
the fuel in the carbs and fuel crossover. Usually when I try
to start it hot I turn the key to run to let the fuel pump
supply cooler fuel to the system, then full choke and hope
catches on the first hit. It does have a new style gear
reduction starter so it cranks well. Thanks for your comments
and ideas in advance !!
–
Bill Gutierrez, '61 OTS '73 OTS
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
In reply to a message from Lundabo sent Sun 11 Aug 2013:
Not to be too pessimistic but if you can
hear a faint clatter when you get off the
gas pedal at 2000-2500 rpm then big end
bearings need to be looked at.–
'91 xjs v12 5.3 early facelift in BRG
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
In reply to a message from Ralph B sent Sun 11 Aug 2013:
Hi My V12 when hot has similar issues. If its been sitting for say
10mins or so, then use about 1/2 accelerator pedal and no choke
when starting.
If this doesn’t work then put accel to the floor and crank till it
starts, will take several seconds of cranking to fire; I’ve got a
minimal exhaust system, and it sounds fabulous when it fires up, a
real jaguar roar.–
The original message included these comments:
the fuel in the carbs and fuel crossover. Usually when I try
to start it hot I turn the key to run to let the fuel pump
supply cooler fuel to the system, then full choke and hope
–
Mark Brown 71 S3 Etype
Ohope, New Zealand
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
In reply to a message from Pele sent Sun 11 Aug 2013:
I used to find that flooring the accelerator helped with a hot
restart. That’s consistent with clearing out the plenums. As soon
as it catches, you have to take your foot off of the accelerator or
else you’ll wake the dead.
kind regards
Marek–
MarekH
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
In reply to a message from MarekH sent Mon 12 Aug 2013:
I have been driving my S3 in temps up to almost 100F with
the fans constantly running and have no hot start issues.
Carbs renovated and float levels set according to manual.
I usually just turn the key without touching the accelerator.
All ignition parts except ballast resistor and Opus is renewed.
Lucky I guess–
Ole-XKE1974
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
In reply to a message from 42southern sent Mon 12 Aug 2013:
To quote from the Jag handbook
‘‘starting when hot-do not use mixture control, it the engine does
not start immediately slightly depress the accelerator pedal when
making next attempt.’’
If your problem relates to the troublesome Opus unit then the next
thing you will notice when the engine is hot will be erratic rev
counter readings, misfiring, then a complete dead cut.–
The original message included these comments:
10mins or so, then use about 1/2 accelerator pedal and no choke
when starting.
If this doesn’t work then put accel to the floor and crank till it
–
Mark Brown 71 S3 Etype
Ohope, New Zealand
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
In reply to a message from 42southern sent Mon 12 Aug 2013:
Thank you everyone for the suggestions. The OPUS unit is long
gone and has been replaced by a Crane unit. Running is never
the issue, it pulls strong up past 6500. It’s just a pain in
the butt to start hot when its sat for 10-15 minutes or so.–
Ralph B - '72 Ser3 V12 2+2 , Middletown, Delaware
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
In reply to a message from Ralph B sent Tue 13 Aug 2013:
On any car that won’t start, first thing to do is to check
to see if you have spark. For your car this isn’t as crazy
as it sounds – even though it runs fine, you could (for
example) have a problem with the cap or rotor, or (if your
car has one) the circuit that makes the coil hotter during
cranking.–
– Joe Augenbraun, Foster City, CA –
Foster City, CA, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
I am continuing the old thread with additional information because when searching it’s handy to have the information in one thread as opposed to scattered in numerous ones. It’s mainly for anyone else to have the information in one as a solution. But maybe I should start a new one?