I'm looking for the ground points (PIS031 and PS051) on the below uploaded diagram. Note I'm aware that PIS08 is the hot side of the coils, but looking for that connection point as well.

The beautiful illustrated coupe 2-page wiring harness diagram does not include engine wiring, "for clarity".

Does anyone have the engine harness diagram with ground points identified??

Or can identify the specific locations in yellow on the attached (the wiring diagrams say things like "front of engine", with no identifying illustration)?

Thanks

 

@panthera999 I can't answer your question but the quick connector guide you referenced is taken from Topix I think. Perhaps someone with a subscription can pull one for the a guide for the engine harness, if there is one, or as I understand it, you can subscribe for as little as one day.

 

I looks like they are soldered joints, not ground points, so presumably somewhere in the wiring loom. That is what the component connector guide calls them anyway.

 

That makes sense so his best option assuming the wires are still in situ is to maybe use string? Coil 4 RW for example and the pic is fuzzy, is 364mm from pin to pin - use a 14 inch string and lay it along the loom to find the joint. Thank you @u102768

 

Here is PI051.

 

Thanks! Is that from the 5.0 service manual, or another document?

 

Electrical Reference Library on Topix so you will need a subscription to see them.

Unfortunately there is an individual PDF for each connector and I lost the will to live when downloading them all when I had a 4.2 so don't have a complete set.

 

So @panthera999 , whatcha up to that started this question?

 

Mostly curiosity -- I'm getting really intermittent (meaning every few weeks) one or two individual misfires on Cylinder 5. Coils are original (85K). Of course, swapped it with Cyl 3, but after that it seemed to continue on 5 and maybe a few on 3, and maybe a few on 1. The degrees rotation of the VVT's is correct and match, so unlikely that. Fuel pressure is good. No effect on performance with the count being almost nil. LTFT is balanced and near zero both sides. O2 sensors new.

But as I'm watching the tube with my wife I scratch away at the issue of what might affect the 1-3-5-7 bank. I mull replacing the coils after 15 years and 85K. I believe they're originally Ford-marked Denso's. But before i consider going there, I'm considering giving all the engine ground points/straps and coil power feeds a good scrub. Probably do that first, since no costs except labor.

Since we're discussing it, would you go with Densos or NGKs to replace the coils?

The result of having access to detailed engine data, and being obsessive about having the Jag work as correctly as a 15 yo car can. Truth is, after two years ownership I'm running out of things to fix. :-)

 

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