[xj-s] 95 aj16 engine coils

XJ-S
1

After testing everything, including testing the ECU in a donner
car. the ECU is ok. The coils are not giving a proper voltage to
the plugs. I was told thay do have 12 volts from the battery. When
the plugs are taken out they are black and oily. The jag mechanic
is at a loss after he has tested all he can think of. Cylinder # 1
is good sometimes, # 2 and #4 are always weak, # 5 and 6 are weak
or nothing at all.

Help! six weeks in repair, no fix.
Thanks ---- Tom–
tomjag95
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–

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2

George Balthrop, Clifton, VA USA
85 & 89 XJ-S Coupes; 89 XJ40 VDP-----Original Message-----
From: tomjag95 thwitkow@roadrunner.com

After testing everything, including testing the ECU in a donner
car. the ECU is ok. The coils are not giving a proper voltage to
the plugs. I was told thay do have 12 volts from the battery. When
the plugs are taken out they are black and oily. The jag mechanic
is at a loss after he has tested all he can think of. Cylinder # 1
is good sometimes, # 2 and #4 are always weak, # 5 and 6 are weak
or nothing at all.

Help! six weeks in repair, no fix.
Thanks ---- Tom

tomjag95
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–

// please trim quoted text to context only

// please trim quoted text to context only

3

Hi Tom,

Sorry for earlier hitting send before adding any response :wink:

If you/your tech don’t have a circuit diagram for the Engine Management
System, go to this site and download the Electrical Guide for your
model:
http://www.captainjaguarscathouse.com/Electrical_Reference.htm

I don’t know much about the AJ16 EMS, but if the ECU works OK in
another vehicle, then it is completing the ground side to the coils as
it should. That leaves either the coils themselves, or more likely a
fault in the 12V+ supply to the coils from the EMS Power Relay, which
is located on the right component panel, right under dash panel. I
would test for proper voltage at each coil White/Brown wire.

George Balthrop, Clifton, VA USA
85 & 89 XJ-S Coupes; 89 XJ40 VDP-----Original Message-----
From: tomjag95 thwitkow@roadrunner.com

After testing everything, including testing the ECU in a donner
car. the ECU is ok. The coils are not giving a proper voltage to
the plugs. I was told thay do have 12 volts from the battery. When
the plugs are taken out they are black and oily. The jag mechanic
is at a loss after he has tested all he can think of. Cylinder # 1
is good sometimes, # 2 and #4 are always weak, # 5 and 6 are weak
or nothing at all.

// please trim quoted text to context only