[xj] No Spark 86 XJ-6

XJ
1

Working on the 86 XJ-6 which has been sitting for a year.
Just reinstalled the fuel injectors after rebuilding by Mr.
SD Faircloth.

Now it appears that I have other issues.

I’m running the ‘‘Cranks but no start’’ checklist and find no
spark. No 12 VDC at the coil but get spark at the plugs
with the jumper from battery + directly to the white coil
wire per step 3 of the procedure.

Has anyone else had this issue and how did you solve it?

Also I don’t hear the fuel pump running yet. Could the two
be related?

I will look into the fuel pump while awaiting advice on the
coil voltage issue.

All advice greatly appreciated.

Brian Mee–
Brian Mee 86 VDP
Manassas / Virginia, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–

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2

In reply to a message from BLS sent Sun 24 Apr 2016:

I would suspect a faulty ignition switch or faulty wiring
from the ignition switch to the coil.

If you (still) have the ballast resistor, are you checking
the voltage with the resistor in place, or removed? Try
removing the resistor and see what happens. It is attached
directly to the coil ‘’+’’ post. Unless, that is, somebody
has already removed it

The fuel pump circuit relies on ‘’+’’ voltage from the
ignition switch as well…so they’re might be a tie-in
between the two problems

Remove the under-dash trim panel and gently jiggle the
wires at the back of the ignition switch. Any change?

Cheers
DD–
The original message included these comments:

spark. No 12 VDC at the coil but get spark at the plugs
with the jumper from battery + directly to the white coil
wire per step 3 of the procedure.

–
Doug Dwyer
Longview Washington, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
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3

In reply to a message from Doug Dwyer sent Sun 24 Apr 2016:

OK, before getting the post from Doug I removed cleaned and
reseated all of the relay connectors for the fuel pump and
starter relays. There was corrosion behind the starter
relay. I cleaned that up and sandpapered all relay
connections.

Result–same no spark no 12 VDC at the white wire. I will
look into the ignition switch next per Doug Dwyer.

Note: fuel pump ran when jumped to the relay wire.

Brian Mee–
The original message included these comments:

I would suspect a faulty ignition switch or faulty wiring
from the ignition switch to the coil.
If you (still) have the ballast resistor, are you checking
the voltage with the resistor in place, or removed? Try
removing the resistor and see what happens. It is attached
directly to the coil ‘’+’’ post. Unless, that is, somebody
The fuel pump circuit relies on ‘’+’’ voltage from the
ignition switch as well…so they’re might be a tie-in
Remove the under-dash trim panel and gently jiggle the
wires at the back of the ignition switch. Any change?

–
Brian Mee 86 VDP
Manassas / Virginia, 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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4

In reply to a message from BLS sent Sun 24 Apr 2016:

Brian:

Yup, I second Doug.
white denotes hot when
ignition switch is on.

In my recent travails,
it was hot at some places and
not so at others and random
in nature.

I removed the ignition switch
and found it very loose and
messed up. I lost a bit of it
as well!!! working over a pan
inadequate. since then, I’ve
heard of working in a plastic
bag.

The ‘‘jump 12v to coil +’’
procedure resulting in spark
says a lot.

One of my long time favorites…

Carl–
The original message included these comments:

Result–same no spark no 12 VDC at the white wire. I will
look into the ignition switch next per Doug Dwyer.

–
Carl Hutchins 1983 Jaguar XJ6 with LT1 and 1994 Jeep Grand
Walnut Creek, California, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
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5

In reply to a message from Doug Dwyer sent Sun 24 Apr 2016:

OK, before getting the post from Doug I removed cleaned and
reseated all of the relay connectors for the fuel pump and
starter relays. There was corrosion behind the starter
relay. I cleaned that up and sandpapered all relay
connections.

Result–same no spark no 12 VDC at the white wire. I will
look into the ignition switch next per Doug Dwyer.

Doug is dead right, Brian - the white circuit, running all engine
management systems, is powered from the ignition switch…

A jumpwire from batt pos to the coil positive will repower the whole white
circuit through interconnections at the ign switch - as a temporary
bypass…

The fuel pump is powered from white, but only when the relay is triggered.
In ‘crank’ the relay is triggered by a connection, white/yellow, on the
starter relay - this circuit, active only in ‘crank’, also runs various
items required specifically in ‘crank’ only. To test fuel pump in ‘crank’;
select ‘R’ or ‘D’ on the gear lever - this will prevent actual cranking due
to the start inhibit switch, making it easier to hear the fuel pump…

The power on white does not directly operate the fuel pump relay; a reed
switch in the AFM closes when the flap opens due to air influx while
running - the pump will not run with ign key to ‘run’ unless the engine is
turning over. To test this function; remove air cleaner and prop the AFM
flap open - the pump will now run whenever the white circuit is powered…

The white and white/yellow has separate connections on the ignition
switch - the two circuits are quite separate…

The gist of all this; check the ignition switch as Doug specifies…:slight_smile:

Frank
xj6 85 Sov Europe (UK/NZ)

Note: fuel pump ran when jumped to the relay wire.

The original message included these comments:-----Original Message-----
From: BLS
Sent: Monday, April 25, 2016 3:07 AM
To: xj@jag-lovers.org
Subject: Re: [xj] No Spark 86 XJ-6

I would suspect a faulty ignition switch or faulty wiring
from the ignition switch to the coil.
If you (still) have the ballast resistor, are you checking
the voltage with the resistor in place, or removed? Try
removing the resistor and see what happens. It is attached
directly to the coil ‘’+’’ post. Unless, that is, somebody
The fuel pump circuit relies on ‘’+’’ voltage from the
ignition switch as well…so they’re might be a tie-in
Remove the under-dash trim panel and gently jiggle the
wires at the back of the ignition switch. Any change?

===================================================
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6

In reply to a message from Frank sent Mon 25 Apr 2016:

Thanks for the information here is the next update:

Removed white electrical part of the ignition switch and
cleaned the contacts. Then realized that there is an inner
white part with springs and 3 more contacts so cleaned that too.

Tried to put it all back together whist standing on my head
under the dash and found that it would not re clip
positively onto the metal portion of the ignition switch
assembly. (Some parts photos seem to show a black rubber
round part around the white ones but there was nothing like
that when I got to the switch on mine.)

Temporarily used some tie wraps to hold it in position but
found that I still had to reach under and hold the two
portions of the switch contacts together to get any results.

Those results were again disappointing. No spark and
probably no fuel pump action either. Cranks though.

I seem to be faced with replacing the ignition switch $$$
and then most likely ringing out the white wire circuit from
there up to the coil.

Brian Mee
Manassas VA–
Brian Mee 86 VDP
Manassas / Virginia, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
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7

In reply to a message from Frank sent Mon 25 Apr 2016:

Thanks for the information here is the next update:

Removed white electrical part of the ignition switch and
cleaned the contacts. Then realized that there is an inner
white part with springs and 3 more contacts so cleaned that too.

Tried to put it all back together whist standing on my head
under the dash and found that it would not re clip
positively onto the metal portion of the ignition switch
assembly. (Some parts photos seem to show a black rubber
round part around the white ones but there was nothing like
that when I got to the switch on mine.)

Temporarily used some tie wraps to hold it in position but
found that I still had to reach under and hold the two
portions of the switch contacts together to get any results.

Those results were again disappointing. No spark and
probably no fuel pump action either. Cranks though.

Powering up the white circuit by jumwiring from batt pos to any white
connection will bypass this function of the ign switch, Brian…

But it is important to regard all this as possibly two different issues;
lack of white power (an ign switch problem), and lack of sparking which
may have other causes.

Jumpwiring batt pos directly to coil pos will power up the ignition system -
which is a separate subsystem requiring no inputs from other management
systems. Cranking the engine should then produce sparks irrespective of ign
key state. If there is still no sparking, the ign system should be addressed
as a separate problem. You should also test for sparking using the coil
centre lead - to eliminate a distributor malady…

The simplest test is then to connect a test lamp between coil neg and
ground - the lamp should be fully lit. While cranking the test lamp should
dim and flicker - implying that the ign amp is operating. However, it
doesn’t guarantee that the ign am is fully functional - it may still
malfunction, failing to trigger sparking. ‘No light’ implies a coil fault -
or a ground short from coil neg…

While in the area; there should be two white wires at coil pos - one from
the ign key, and one to the ign amp. At coil neg there should be 3 wires;
one black/white to the ign amp, one black/white to the ECU and one
white/slate blue to the tacho. No other way of connecting is
permissible…:slight_smile:

Frank
xj6 85 Sov Europe (UK/NZ)

I seem to be faced with replacing the ignition switch $$$
and then most likely ringing out the white wire circuit from
there up to the coil.-----Original Message-----
From: BLS
Sent: Tuesday, April 26, 2016 1:57 PM
To: xj@jag-lovers.org
Subject: Re: [xj] No Spark 86 XJ-6

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8

In reply to a message from Frank sent Tue 26 Apr 2016:

Brisn:

Others have reported servicing the
ignition switch in situ.

Not me, thought. Tough enough on the
bench!!!

Dropping it out is fiddly, but
doable. Remove the lower ‘‘clam shell’’
jnst under the wheel. I busted it partly!!

Then tackle the two ''break away screws
that secure the switch in the mount.
Several methods to get a bite on them.
Mine were not tight at all. I found
wire nut just right. I drilled a hole
perpendicular to it’s long axis. A nail
went there as a lever. Front one easy,
back one a bit fiddly. Replacements are
available. I used an Allen head from my
stash for one and reused one with the
wire nut tool.

Once out and on the bench I opened it
over a pan. I found a mess. Lost one
of the teeny rollers… Maybe two???

Lesson learned elsewhere: Should you
choose this mission, work in a large
clear plastic bag to catch the stray
parts!!

I decided mine was way too loose by
wear partly by age and partly by a
heavy key ring.

I got a sound used unit via David
Boger of everydayxj. Perfect. A lot
of things now work as they should!!!

Carl–
The original message included these comments:

Removed white electrical part of the ignition switch and
cleaned the contacts. Then realized that there is an inner
white part with springs and 3 more contacts so cleaned that too.
Tried to put it all back together whist standing on my head
under the dash and found that it would not re clip
positively onto the metal portion of the ignition switch
assembly. (Some parts photos seem to show a black rubber
round part around the white ones but there was nothing like
that when I got to the switch on mine.)
Temporarily used some tie wraps to hold it in position but

–
Carl Hutchins 1983 Jaguar XJ6 with LT1 and 1994 Jeep Grand
Walnut Creek, California, 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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9

In reply to a message from Frank sent Mon 25 Apr 2016:

Frank,
I am currently working on the same problem with my 86
Jaguar. I was trying to find a draw on the battery and tried
to start the car with it in N now it won’t start at all.
Would starting in neutral bglow a relay or something? We can
start the car by jumping the hot lead on the 22RA lucas to
the 30 terminal on the relay. I have replaced the red and
black replays. Any suggestions?
Jimgrass–
James Grasmehr
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
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10

In reply to a message from Jimgrass sent Fri 29 Apr 2016:

There’s nothing inherent in the design of the circuits that
would allow or create damage by starting in neutral. I
suspect a suspicious appearing but innocent coincidence.

Is this a case where the engine won’t crank, or cranks but
won’t start?

Are you referring to the starter relay in saying ‘‘22RE’’?

And, you’re jumping to terminal 30 of which relay?

Cheers
DD–
The original message included these comments:

Would starting in neutral bglow a relay or something? We can
start the car by jumping the hot lead on the 22RA lucas to
the 30 terminal on the relay. I have replaced the red and

–
Doug Dwyer
Longview Washington, 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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11

In reply to a message from Frank sent Mon 25 Apr 2016:

Frank,
I am currently working on the same problem with my 86
Jaguar. I was trying to find a draw on the battery and tried
to start the car with it in N now it won’t start at all.

I second Doug, Jim…

Cranking in ‘N’ has absolutely no detrimental effects on anything - ‘our’
Jaguars are configured to crank, and start, either in ‘P’ or ‘N’…

Assuming you have a ‘no crank’ situation using the ign key to ‘crank’ - when
cranking by jumping the starter relay the engine will crank and start.

There is only one relay involved; the starter relay - working on any other
relay has no effect on cranking. We assume you are jumpwiring starter relay
brown to white/red and the engine cranks…right? This jump bypasses the
relay function - powering the starter solenoid directly.

Now jumpwire starter relay brown to white/yellow - this simulates ign
key to ‘crank’. if the engine cranks and starts you have lost the ign key
crank power - an ign key problem. (You can back up this test by checking for
power on white/yellow with key to ‘crank’).

If no crank; jumpwire relay black/green to a good ground, and use key to
‘crank’. This jump bypasses the start inhibit switch - and if the engine now
cranks with the key; the start inhibit is the problem…to be pursued.

If still ‘no crank’ with the white/yellow powered and the black/green
grounded the starter relay has failed…

Frank
xj6 85 Sov Europe (UK/NZ)

Would starting in neutral bglow a relay or something? We can
start the car by jumping the hot lead on the 22RA lucas to
the 30 terminal on the relay. I have replaced the red and
black replays. Any suggestions?-----Original Message-----
From: Jimgrass
Sent: Saturday, April 30, 2016 9:35 AM
To: xj@jag-lovers.org
Subject: Re: [xj] No Spark 86 XJ-6

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12

In reply to a message from Frank sent Sat 30 Apr 2016:

Bits and pieces:

  1. All automatic cars that I’ve dealt
    with are made to crank and start in
    Neutral as well as Park. Either should
    work just fine as long as the car is at
    rest.

The added reason for a Neutral crank
and start is one of safety. should the
engine stop running while in motion,
it can be refired. Thusly restoring
power steering and brakes. The safety
thing.

  1. Way back when, I attached an
    extra wire to the starter solenoid.

a. Crank the engine but not start it.
b. Emergency crank. If the relay or
it’s circuitry fails. Merely,
turn the ignition switch to run
and touch the wire to battery +.
Caveat: Make d… sure the car
is in Park!!

Some cars have an ‘‘emergency crank’’
under the hood.

Carl
ah–
The original message included these comments:

I am currently working on the same problem with my 86
Jaguar. I was trying to find a draw on the battery and tried
to start the car with it in N now it won’t start at all.

–
Carl Hutchins 1983 Jaguar XJ6 with LT1 and 1994 Jeep Grand
Walnut Creek, California, 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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