[xj] xj6 series 4: start problem

Hello.

My lovely XJ6 is still having start problems. If it stands
for two weeks it won’t start (battery is full, it has ample
fuel in tank and the starter engages and pulls the engine
around). The only remedy seems to be to leave the car
standing with the rear end high up for a few days and then
try again.
So it seems like the fuel pulls back to the tank when it
stands flat and that there is not enough fuel reaching the
engine, unless it has been standing with the rear high.

Do any of you series 3 geniuses have advice?

Any help very welcome.

Knut–
Knut_XJ6_s3_86
Oslo, Norway
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Hello.

My lovely XJ6 is still having start problems. If it stands
for two weeks it won’t start (battery is full, it has ample
fuel in tank and the starter engages and pulls the engine
around). The only remedy seems to be to leave the car
standing with the rear end high up for a few days and then
try again.
So it seems like the fuel pulls back to the tank when it
stands flat and that there is not enough fuel reaching the
engine, unless it has been standing with the rear high.

It’s either a coincidence, Knut - or sign of some deeper trouble…

While there is a non-return valve, preventing the fuel from draining off the
fuel rail; this valve sometimes fail - but this has minimal effect on
starting, and none on running. If the pump runs and works, and is suitably
provided with fuel from the tanks - the rail is re-pressurized within a
couple of seconds…

Questions arising; when/if the car starts, what is cold idle? And when hot;
what is hot idle and does the car perform as it should. And does it crank
‘briskly’…?

While standing for a couple of weeks (inside or outside) is no big deal, it
may cause condensation and short in the high tension leads - and of course
cause other connections. Open the hood in the dark, and crank while looking
for telltale flashing indicating shorts. If so carefully wipe dry all high
tension leads, including dist lid, to get rid of moisture. You may also,
after drying lead, spray leads with silicone spray…

Next step is to verify sparks; gap a spare spark plug to 3 mm (1/8"),
connect to any plug lead - and crank. Spark should be strong and blue; weak
or no spark may indicate an ignition problem - to be addressed.

There may be a fuelling issue, unless the car actually runs well when
started. Otherwise, initial steps includes; set the gear lever to ‘R’ (or
‘D’) and turn key to ‘crank’. You should hear the pump running - if not;
pursue further. Next; remove air filter and prop open the AFM - the pump
should now run with the key to ‘run’. With the pump running; open filler
lids and listen to fuel returning to the tank selected…

With no fuel return; a fuel pressure test is ‘best option’ - though again if
the engine runs OK once started, the fuel return should be there…

These are only initial steps to clarify the issues - there are such a lot of
things that may pervent starting…:slight_smile:

Frank
xj6 85 Sov Europe (UK/NZ)

Do any of you series 3 geniuses have advice?

Any help very welcome.-----Original Message-----
From: knut3000
Sent: Friday, September 16, 2016 9:14 AM
To: xj@jag-lovers.org
Subject: [xj] xj6 series 4: start problem

===================================================
The archives and FAQ will answer many queries on the XJ series…
FAQs: http://www.jag-lovers.org/xjlovers/xjfaq/index.html
Archives: http://www.jag-lovers.org/lists/search.html

To remove yourself from this list, go to http://www.jag-lovers.org/cgi-bin/majordomo.

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