The car has no power what so ever although it tick over perfectly.
I have checked the distributer output all leads fine. I have
checked the injectors listening through a screwdriver all ticking
away.
I have now noticed that there are unequal gas pressures coming from
the exhausts. On the passenger side (near side UK) the exhaust gas
is coming out of the exhaust is at a lower pressure than the
drivers side (off side UK). The gases out of the passenger side
are also much cooler. On the driver side tail pipe here is a
blackening suggesting a richness of mixture. On the passenger side
tail pipe they is no blackness. Do these symptoms mean anythig to
someone out there and would they be symptomatic of lack of power?–
Ansam
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In reply to a message from Ansam sent Wed 28 May 2008:
It would be nice to know what year and type engine V-12 S-6, and
the number of miles on the engine/ car. I am asuming that it’s a V-
12 and has 115K miles on it.–
BarryE
Woods Cross, Ut, United States
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It sounds like you have no spark (or weak spark) on the B bank (left
vehicle side). If the power level is VERY diminished, you have at
least several cylinders that are not producing power, and if the idle
is smooth, then the entire bank is likely not firing, so that you are
running on the A bank only. That would be consistent with the
difference in the exhausts that you describe.
I would suggest removing the B bank coil HT lead from the top of the
distributor (the one that is off-center), anchoring its metal end 1/4"
from ground, and seeing if you get a BLUE spark that easily jumps the
gap to ground. If you get a yellow spark, you have a problem in the
power module, coil or associated wiring on that side.
If the HT spark from the B bank coil is BLUE, then remove several of
the plug wires on the B bank and test for spark/color.
George Balthrop, Clifton, VA USA
85 & 89 XJ-S Coupes; 89 XJ40 VDP-----Original Message-----
From: Ansam asdangerfield@hotmail.co.uk
The car has no power what so ever although it tick over perfectly.
I have checked the distributer output all leads fine. I have
checked the injectors listening through a screwdriver all ticking
away.
I have now noticed that there are unequal gas pressures coming from
the exhausts. On the passenger side (near side UK) the exhaust gas
is coming out of the exhaust is at a lower pressure than the
drivers side (off side UK). The gases out of the passenger side
are also much cooler. On the driver side tail pipe here is a
blackening suggesting a richness of mixture. On the passenger side
tail pipe they is no blackness. Do these symptoms mean anythig to
someone out there and would they be symptomatic of lack of power?
In reply to a message from BarryE sent Thu 29 May 2008:
It is a 1992 V12 5.3 convertable. It has covered 62K
kilometers approx 40K UK miles
Thanks for your interest
Tony–
Ansam
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In reply to a message from Ansam sent Fri 30 May 2008:
Your XJ-S V12 HE engine is likely to be equipped with the Marelli
distributor, which, according to Kirby Palm’s excellent treatise on
the Jaguar V12 engine, can suffer a fault where only one bank fires
and the other doesn’t. It also advises you to be careful when
you’re in this condition. You’re effectively pouring unburnt and
very combustible air/fuel mixture from a whole bank’s (Bank B)
worth down the exhaust. Mind that you don’t risk explosion.
The cure is in Kirby’s book, which is available free on this site.
To confirm that Bank B is not firing you can carefully sniff at the
exhaust (again be aware of the poisonous air/fuel mixture, or CO
from poor combustion, etc). Have someone oversee what you’re doing
so your safety is guarded.
Continued lack of power 1992 V12 5.3
Many thank for tip I have removed the HT lead from the left
bank isolated it and restarted the engine. The drive is
exactly the same as before so I think you have proved forme
there is a problem with the B bank. Is there any way of
testing the coil or the power module. Can I simplly
interchange the components from A bank, as I know they work,
with the duff components from B bank? Thanks again for all
your help–
Ansam
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// please trim quoted text to context only
Kirbert
(Author of the Book, former owner of an '83 XJ-S H.E.)
7
Ansam wrote:
Is there any way of
testing the coil or the power module. Can I simplly
interchange the components from A bank, as I know they work,
with the duff components from B bank?
Yes, you can, but you must make sure and swap all the connections to
each component. When you swap HT leads between coils, for example,
you must swap the other connectors to the coils as well.
Unfortunately, some wires might not reach, you might have to
physically relocate some components to make the swaps.
Also, you should swap connectors on only one pair of components at a
time. For example, just do the coils first. If the problem switches
banks, you know you have a bad coil. If the problem is unchanged,
you know both coils are good, move on to swapping the power modules.
In reply to a message from Kirbert sent Fri 30 May 2008:
I have been reading your conversations since your first posting. I
have a 92XJS v12 conv with 89000 miles. It acquired the same
symptoms as yours - dragging the same tank, little right exhaust
pressure or temperature - at about the same time, with the addition
of a FF13 fault code. Another posting titled, Fuel Fail 13
code, '92 XJS V12, suggested replacing the distributor cap and
rotor to eliminate the code. My car has an original Marelli
distributor cap and rotor. They are both clean and unburned. I
read Kirby Palms suggestions, performed his preventative fix,
cleaned all the contacts and reassembled the distributor with no
change at all. I removed the lower right catalytic converter,
planning to gut it and reinstall, but a previous owner had already
beat me to it - upper and lower - I hope he did both sides. This
morning I disconnected the offset coil wire from the distributor
cap to the front coil, clamped it and cranked the engine -
resulting in a blue spark and not engine starting. I did the same
with the center coil wire to the rear coil - resulting in no spark
and the engine starting, left bank only as usual. I tested one
plug on each side to verify the coil results. The left plug, 3b,
sparked as the engine started. The right plug, 4a, did not spark
and as the engine started. My current conclusion is that the rear
coil or amplifier for the right bank have failed. I have found a
new coil for $96 US and an amplifier for $285 US. The coil shoud
arrive on site Wednesday. I will try that before I invest in the
amplifier. I will let you know if this works for my cat. I
appreciate your lead on this journey and the contributions from all
your responders.–
The original message included these comments:
Ansam wrote:
Is there any way of
testing the coil or the power module. Can I simplly
interchange the components from A bank, as I know they work,
with the duff components from B bank?
Kirbert
(Author of the Book, former owner of an '83 XJ-S H.E.)
9
WCF IV wrote:
My current conclusion is that the rear coil or
amplifier for the right bank have failed. I have found a new coil for
$96 US and an amplifier for $285 US. The coil shoud arrive on site
Wednesday. I will try that before I invest in the amplifier.
It wasn’t worth $96 to you to swap coils to see if one was bad?
BTW, I think you should be able to buy a generic Bosch amp for
perhaps half that.
In reply to a message from Kirbert sent Tue 3 Jun 2008:
Thanks for the suggestion. I just switched the front (left bank)
coil for the rear (right bank) coil. Started the engine and the
right bank fired off - greater exhaust pressure, hot exhaust after
a minute of idle. The left bank went dead, as the right bank was
originally. The coil wire spark test also reversed. I’m pretty
sure the original rear (right bank) coil is the primary cause.
I did a little more online research on coil price and availability.
Found one for $135 US and one for $32 US. I tried to find one
locally, but no-one in my area stocks them. I’m surprised (naive?)
at the range.–
The original message included these comments:
WCF IV wrote:
My current conclusion is that the rear coil or
amplifier for the right bank have failed. I have found a new coil for
$96 US and an amplifier for $285 US. The coil shoud arrive on site
Wednesday. I will try that before I invest in the amplifier.
It wasn’t worth $96 to you to swap coils to see if one was bad?
BTW, I think you should be able to buy a generic Bosch amp for
perhaps half that.
– Kirbert
In reply to a message from stephen sarmanian sent Wed 4 Jun 2008:
About a year ago, I bought a coil at Autozone for about $60.00–
Maynard 94 XJS V12 Coupe 91XJS(RIP) 86XJ6 78MGB 67MGB
Niles, IL, United States
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Thanks, I checked various sources as did William who started the thread, and
the range is indeed very wide for aftermarket coils as he reported, from $32
(XK’s Unlimited) USD to $125 (Importcatalogue.com) that I saw. I don’t know
the manufacturer, perhaps some are really the same item.
Genuine Marelli coils seem to be priced about $135 or so (Jagbits), though I
don’t know if there’s any appreciable quality difference between aftermarket
vs Marelli, since the Marelli’s being replaced have failed in service. But
some photos of aftermarket items show different connectors and different
style construction aroud the metal side pieces. I’ll check a bit further and
then opt for one of the Jag parts suppliers among those frequently mentioned
in this forum.
In reply to a message from stephen sarmanian sent Thu 5 Jun 2008:
I just installed the new coil ($95 US from Welsh Enterprises Inc.),
and the power problem was resolved. The FF13 fault code is gone,
but the check engine light is still on. I will try a few more
miles, if that doesn’t eliminate the light, then I’ll try
disconnecting the battery for a bit to see if it goes away. Any
other suggestions?
The new coil is from Marelli, but without the Marelli marking on
it, it is stamped Made in China, otherwise it is identical to the
original. The Kirby Palm book indicates Marelli is starting to
outsource some electrical components instead of manufacturing them
themselves.–
WCF IV - 92XJS v12 Conv
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The car has no power what so ever although it tick over
perfectly.
I have checked the distributer output all leads fine. I have
checked the injectors listening through a screwdriver all
ticking
away.
The problem has been solved finally. It was the wiring loom
to two of the injectors. The insulation had broken down
causing a short that in turn prevented the A bank receiving
fuel. Thanks for everyones adviceFrom: Ansam