have you got spark on both banks..?

 

You can also get a coil on plug tester....just place it on the coil and will tell you if it is firing.

Do a hard reset (disconnect battery 5 minutes) see if it then fires up. I always try the hard reset first....lol

 

Greetings Red,

Maybe you don't have any DTC codes stored, it seems you would have P0300, or P0351 thru P0354, or P0355 thru P035. That would show either random missfire or one bank of dead coils.

Both ignition modules, and the coils, are powered through one relay. So that's out of the equation.

The two modules are the same, LJA1450AF. I verified this on a parts car, and checked if there was enough wiring harness to see if you could switch connections between the two: no problem.

Try that, and the live bank and dead bank should now be switched also. If that test does not identify a bad ignition module, then you have a wiring harness fault or no signal to the dead bank's module from the ECM. Hope for the module. Good hunting!

 

Hey Red,

Unless your ECM or dianostic socket is brain-dead, you will always get either P1000 or P1111. That just tells you the lights are on, and whether or not somebody is home.

Try switching the modules.

Please let us know what you find.

 

Sounds like you need to purchase a wiring diagram.

On Figure 04/02 of mine, for 1997 N/A Engine management, the power feed is from the ignition coil relay and splices off to power both of the ignition modules and all eight coils. All of these wires are Purple/ white, they all should have 12V with the key on, and yours probably do. I didn't look this far, but I presume that you could test each coil PW wire for continuity to ground (short) by turning off the key, disconnecting the ignition module, and testing.

The other wire to each coil is as follows:

B (left) 1: Green/ black
2: Green/ red
3: Green/ orange
4: Green/ purple

The diagram shows these ECM- controlled ground wires as running directly from the B bank ignition module directly to each coil. The only intermediate point of connection is P11, pins 43-46. I did not find P11 in the wiring diagrams, and I am looking on my WDS to identify it positively. I suspect it is the big Sumitomo block connector for the engine wiring harness. Those spade terminals can corrode, I clean them with contact cleaner and a flexible emery board that I stole from my girlfriend's manicure toolbox.

Test each Green/..... wire from module connector to coil for continuity and short to ground also, hopefully you will find a problem.

Andrew Bernstein

 

Hey Red,

My mistake, it is connector PI1, not P11. That is shown as PI001 on the WDS, which is the big black Sumitomo connector I was talking about. Not much more I can do without looking at the car for myself, good hunting.

 

Hey Andrew,
Hope you are well......and just putting in my 2 cents as usual....lol
in the diagram, I don't have mine handy....does it show the 2 ignition modules, Module 1 controlling something like A1, B2, B3, A4 and the Module 2 controlling B1, A2, A3, B4? I cannot remember exactly, but if this is the case there should be spark on 2 coils on 1 bank and 2 on the other.
Maybe check all 8 plugs for any spark. I think if no spark on 1 bank only.....could be larger issue looming...ie ECM as all on 1 bank only common place is ECM. Also maybe the reason for no codes storing.
We have had many 97 ECMs failing and this is the symptom.

 

Question.

When an ECM is rebuilt by whoever you pick, would they be able to tell you what circuit/resistor they replaced/resoldered ?

It would seem to me that it is not the ECM that goes bad but the part that shorts out the ECM. That part should be replaced along with the ECM rebuild (around $400) so it does not happen again.

Mine had a bunch of codes, including crank position sensor. ECM was rebuilt but still had hard starts. Codes cleared by dealer and I ordered aCPS. Hoping car will start even better after new CPS.

I dunno, I'm just rambling.
Good luck with your car, Red.

 

Greetings FJT,

You are EXACTLY correct as usual, thank you for pointing out my mistake. Red, apologies to you if I wasted any of your time. The module swap was still relevant, but the color codes for signal wires I gave you was incorrect for two coils. If you haven't found a big problem to the left bank coils, like where the harness goes under the coil cover, your news might not be good at all. FJT, thanks for your additional info. Best wishes,

Andrew Bernstein

 

Hey guys speaking of under the coil covers. I just scored a 1997 Jag XK8 Coupe from Florida which is where perhaps I should have left it. Anyway, one of the first things I do is change the plugs to verify engine condition. While trying to unplug the coils the plugs were disintegrating in my hands, falling apart like peanut brittle. The right bank were siliconed together....HELP. This is not a situation that is ideal. My question is can it be repaired???? Looks like bocu cash. Thank-you for any suggestions here. I think everything is OK for the present moment but I would really like to resolve this issue. The plugs came out real clean. The car has 76000 miles on it and I paid way over book for it. These Coupes are very rare. Black with coffee interior. look forward to any ones input. Thanks in advance!

 

@paintexpert - not quite certain what you are asking .. .are you trying to avoid buying replacement plugs & coils? Got a picture, maybe?

jonscot - down in that Florida heat ....