Can a broken wire to the O2 sensor prevent a '94 XJ6 from starting?
I recently replaced the head gasket and the vacuum lines and now
the cat won’t start. I’ve searched the forums, followed the checks
and still nothing. Other than than the smoke from the blown head
gasket, it ran fine before.
Top dead center was set per the Haynes manual, it cranks, tach
moves when cranking, it has spark at the plugs (replace ignition
coil), the plugs are wet with fuel, compression is good, no VCM
error codes, the under hood relays are clean and the battery has a
full charge. If the CPS were out I wouldn’t get spark, right?
Is there a circuit that gives the engine the OK to run?
Hard to mess up the vacuum lines but could that be the gremlin?
What am I missing gents?
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In reply to a message from Brazierje sent Fri 20 Jan 2012:
It may be flooded if the valves/plugs are wet with fuel. Stepping
the throttle pedal to the floor while cranking turns the injectors
off to clear a flooded condition. Try that.–
The original message included these comments:
Top dead center was set per the Haynes manual, it cranks, tach
moves when cranking, it has spark at the plugs (replace ignition
coil), the plugs are wet with fuel, compression is good, no VCM
error codes, the under hood relays are clean and the battery has a
full charge. If the CPS were out I wouldn’t get spark, right?
Is there a circuit that gives the engine the OK to run?
Hard to mess up the vacuum lines but could that be the gremlin?
What am I missing gents?
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In reply to a message from Jaguarpete sent Fri 20 Jan 2012:
I have tried that and it still won’t start up.–
The original message included these comments:
It may be flooded if the valves/plugs are wet with fuel. Stepping
the throttle pedal to the floor while cranking turns the injectors
off to clear a flooded condition. Try that.
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In reply to a message from Brazierje sent Fri 20 Jan 2012:
Well, it has to be something that you have (or have not)
done!
Did you set the distributor timing correctly at TDC on the firing stroke?
Did you remove the distributor during the head gasket
change/ If so, did you replace it so that the rotor is
pointing at #1 plug-lead pick-up when the engine is at TDC #1 cylinder on the firing stroke?–
The original message included these comments:
I recently replaced the head gasket and the vacuum lines and now
the cat won’t start. I’ve searched the forums, followed the checks
and still nothing. Other than than the smoke from the blown head
gasket, it ran fine before.
What am I missing gents?
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In reply to a message from Bryan N sent Fri 20 Jan 2012:
I just came in from checking that. With the crankshaft sensor ring
set to top dead center for the #1 cylinder The rotor is pointing
directly at the #1 plug lead.
Anything else I could check?–
The original message included these comments:
Did you set the distributor timing correctly at TDC on the firing stroke?
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In reply to a message from Brazierje sent Fri 20 Jan 2012:
Yes, but the engine can be at TDC #1 cylinder on the exhaust stroke when that pointer is aligned as well as on
the firing stroke.
Try this.
Rotate the engine to TDC #1 cylinder with the rotor arm
pointing directly at the pick-up for #1 plug lead as you
have described and mark the pick-up position in the cap on
the distributor body
Then remove the distributor.
Rotate the engine one complete revolution in the clockwise
direction as viewed from the front (i.e exactly 360�) so
that pointer is again properly aligned and then re-fit the
distributor, ensuring that as it is lowered in to engagement
with the worm drive the rotor still aligns exactly with the
mark you made on the body as the position of the pick-up for #1 plug lead.
Then try to start it.–
The original message included these comments:
I just came in from checking that. With the crankshaft sensor ring
set to top dead center for the #1 cylinder The rotor is pointing
directly at the #1 plug lead.
Anything else I could check?
The original message included these comments:
Did you set the distributor timing correctly at TDC on the firing stroke?
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In reply to a message from Bryan N sent Fri 20 Jan 2012:
I did as you suggested. Now it is acting like it wants to start,
more than just cranking. But still not starting.–
The original message included these comments:
Rotate the engine to TDC #1 cylinder with the rotor arm
pointing directly at the pick-up for #1 plug lead as you
have described and mark the pick-up position in the cap on
the distributor body
Then remove the distributor.
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With respect to the previous cranking atttempts, I would try the pedal to
the metal again just in case the engine is still flooded.
Regards Robin O’Connor
'92 XJ40 4.0 Ltr
Auckland NZ----- Original Message -----
From: “Brazierje” brazierje@aol.com
To: xj40@jag-lovers.org
Sent: Saturday, January 21, 2012 10:01 AM
Subject: Re: [xj40] O2 Sensor No Start '94 XJ6
In reply to a message from Bryan N sent Fri 20 Jan 2012:
I did as you suggested. Now it is acting like it wants to start,
more than just cranking. But still not starting.
The original message included these comments:
Rotate the engine to TDC #1 cylinder with the rotor arm
pointing directly at the pick-up for #1 plug lead as you
have described and mark the pick-up position in the cap on
the distributor body
Then remove the distributor.
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Line Books and more !
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In reply to a message from Brazierje sent Fri 20 Jan 2012:
Yes, a failure of the EMS Main relay (the one in the black
base in that group of relays on the firewall in the engine
bay) - but that would prevent the fuel pump from working
during cranking too.
But I thought you reported that the plugs are wet with fuel
after cranking so presumably the injectors are working -
otherwise how is the fuel getting in there?–
The original message included these comments:
It may be flooded but I’ll need to recharge the battery before I
try again.
Aside from flooring it, is there another way to interupt the
injectors?
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In reply to a message from Brazierje sent Fri 20 Jan 2012:
Now you have gone that far, if you think that improved
things, you may need to check precisely the valve and
distributor ‘timing’ in relation to TDC #1 cylinder (and
physically check the TDC of #1 piston using a probe through
the plug hole) and to be sure of that you will need to
remove the cam cover again to check both.
If the distributor ‘timing’ is pretty close, try rotating
the distributor in the slot for the fixing bolt to see if it
improves or worsens the problem.–
The original message included these comments:
I did as you suggested. Now it is acting like it wants to start,
more than just cranking. But still not starting.
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In reply to a message from Brazierje sent Fri 20 Jan 2012:
One other horrible thought just occurred to me.
Please do not take offence at this suggestion, but it has
happened to others who have removed the camshafts in
replacing the head gasket.
Have you refitted the inlet and exhaust camshafts in their
correct sides? They look identical and are - except for the
timing slot in the front flange (where the cam timing tool
fits). A quick visual check is that at TDC #1 cylinder on
the firing stroke, the pointed lobes of the two camshafts
should be pointing inwards towards each other at an angle of
about 40� to the vertical line through the axis of the valves.–
The original message included these comments:
I did as you suggested. Now it is acting like it wants to start,
more than just cranking. But still not starting.
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In reply to a message from Bryan N sent Fri 20 Jan 2012:
I didn’t remove the camshafts from the head when I replaced the
gasket. But I may have rotated one when I reinstalled the timing
chain. I’ll return it to top dead center, remove the cover and take
a look.–
Merlin 1994 XJ6
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
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If you mean is there another way to stop the injectors firing and flooding
the engine then yes you can remove the fuel pump relay that will stop the
fuel delivery.
However it is a function of the EMS to recognise that when the engine is
turning but not running and the TPS registers WOT then it shuts off the
injector pulse.
Regards Robin O’Connor
'92 XJ40 4.0 Ltr
Auckland NZ----- Original Message -----
From: “Brazierje” brazierje@aol.com
To: xj40@jag-lovers.org
Sent: Saturday, January 21, 2012 10:26 AM
Subject: Re: [xj40] O2 Sensor No Start '94 XJ6
In reply to a message from Robin and Maureen O’Connor sent Fri 20 Jan
2012:
It may be flooded but I’ll need to recharge the battery before I
try again.
Aside from flooring it, is there another way to interupt the
injectors?
The original message included these comments:
With respect to the previous cranking atttempts, I would try the pedal to
the metal again just in case the engine is still flooded.
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services and resources including Photo Albums, Event Diary / Calendar, On
Line Books and more !
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In reply to a message from Brazierje sent Fri 20 Jan 2012:
Bryan N
Took your advice and removed the cover and check the camshafts.
Good call.
The intake was off by about 10 deg and the exhaust by about 20 deg.
I set both camshafts to TDC, reinstalled the cover and it fired
right up.
You have saved me a bundle.
Thank you very much.
But now I have a new problem. The valve cover cracked when I
torqued the two forward center screws. (will it never end)
The '94 XJ6 has the oil fill cap on the valve cover, I have seen
the side filler tubes on some other years of the XJ6. Are there any
other year XJ6s that have the same valve cover as the '94?–
The original message included these comments:
I didn’t remove the camshafts from the head when I replaced the
gasket. But I may have rotated one when I reinstalled the timing
chain. I’ll return it to top dead center, remove the cover and take
a look.
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In reply to a message from Brazierje sent Fri 20 Jan 2012:
Pleased you have the starting problem sorted.
The cam cover on your car is the one fitted to 3.2 and 4.0
litre AJ6 engines from engine serial number (not VIN)
E116000. I’m not sure if that came in at the beginning of
the '93 model year or some time later through to the end of
XJ40 production in '94 but it was not continued in to the
AJ16 engines on the X300. They have a completely different
cover to cater for the ‘coil-on-plug’ devices (although they
may still bolt on an AJ6 head, but I don’t really know about
that).
The part number of the cover with the oil filler cap is
EBC11564 and is still available as a new spare from JDHT for
about $200 USD plus tax and shipping whereas the earlier one
without the oil filler cap is part number EAC4989 and is
‘NLA’ from Jaguar.
No doubt there are plenty of '94 model XJ40s in breaker’s
yards which could be pillaged to get a sound cam cover
because there is virtually zero demand for replacement
engines. Try somewhere like Coventry West or Motorcars Ltd -
I believe they have engines and may have a surplus cover.–
The original message included these comments:
But now I have a new problem. The valve cover cracked when I
torqued the two forward center screws. (will it never end)
The '94 XJ6 has the oil fill cap on the valve cover, I have seen
the side filler tubes on some other years of the XJ6. Are there any
other year XJ6s that have the same valve cover as the '94?
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In reply to a message from Bryan N sent Sat 21 Jan 2012:
The reason I was asking is that there are several wreaking yards in
the Atlanta area and they have just about every year XJ6 accept
the '93’94 models.
What is your opinion on using cold weld (JB Weld) to fix cracks in
aluminum cam covers? The cracks are in the center area.–
The original message included these comments:
No doubt there are plenty of '94 model XJ40s in breaker’s
yards which could be pillaged to get a sound cam cover
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In reply to a message from Brazierje sent Sat 21 Jan 2012:
If the cracks are not structurally significant - e.g around
an attachment hole, I would have thought JB weld would be
good enough to hold it together.
I’m a bit puzzled - how did it get cracked in the first
place? The attaching screws should never be over-tightened
otherwise the cover will distort and be a permanent leak source.–
The original message included these comments:
What is your opinion on using cold weld (JB Weld) to fix cracks in
aluminum cam covers? The cracks are in the center area.
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In reply to a message from Bryan N sent Sat 21 Jan 2012:
In the Haynes manual the torque for the cover screws is 89 to 106
in-lbs. I torqued then to 100 in-lbs, the two forward center screws
didn’t make it. (I said a few choice words when it happened)
I’ll clean up the area with a Dremmel and try the JB weld. I the
meantime I’ll look for a replacement just in case.–
The original message included these comments:
I’m a bit puzzled - how did it get cracked in the first
place? The attaching screws should never be over-tightened
otherwise the cover will distort and be a permanent leak source.
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