Yep, that makes sense.
Borescope inspection is definitely the way to go.

 

Gees, this is heavy going.

Could you put the whole picture in Chronological order from the beginning.

I am imaging something like this.

1. Car taken in for CW front Y pipe renewal for Leakage of the forward CW pipes?
2. Dealer replaces said CW pipes, and water pump.
3. Also changes the ECU software ? nice but why??.
4. Owner gets car returned and drives crap.
5. Car returned to dealer for investigation.

Some questions.

• How long was the car at the dealer changing out the CW pipes and the water pump? (Busy dealer and milk it, a bit so about 2 weeks+.)
• What codes were found before and after the CW Y pipe change out?

Possible, Plausible Explanation.

I would suggest, with the engine being open and the fuel system being depressurised for extended time? (2 weeks plus). Outside cold and/or dampish air with the supercharger off, HP fuel pipe removed etc.

The No.5 Cylinder injector, and may be more, have gone bad, sticking. LH bank mid. etc. may be more in the beginning due to moisture etc.
Dealer finds in runs badly, and changes the ECU program to smooth it out, hide it etc.
Good enough to get it out the shop, without engine light while it continues to drive badly, and pumps fuel into Cylinder No.5 melting the piston top.
Returned to dealer, and new engine required.

So, all engine codes, and boroscope of the No.5 piston crown please.
Miles driven since Y pipe replacement.

Depending on the feed back, you may have to have an independent engineers write a report on the car condition and finds and suggest the dealer replace the engine. This could be tricky without all the evidence being available.

Yes a V5 would drive differently.

 

You are very correct. There was no design input other than back of napkin. The only thing Ford contributed to this engine design was quality management systems in the plant, which JLR sorely needed in the early 2000s.

There is a real mystery as to when OP's cylinder was damaged, agree boroscope inspection by independent 3rd party to verify possible cause would be interesting. Based on what you've suggested, it seems like you have a compelling reason to escalate to this dealer's General Manager and if able to document, possibly JLR NA. I do not know how amenable the parties will be, but with enough evidence and well propositioned history, I think you have a case.

 

When the car logs and stores codes, aren't they time and date stamped? Not sure how long that data is kept, but prob good to download anything you can as that might indicate when codes were first logged. Even without the CEL illuminated it could be logging codes.

 

Just logged in today after a long, long time. This failure is exactly the same as I had at 38,000 miles. Someone else on this forum experienced the exact same thing. Inserting a bore scope in the plug hole of the 0psi compression cylinder will probably reveal a hole in the top of the piston with none of the usual evidence that might indicate detonation. Some of the early F-Type AJ126 engines were well equipped with flawed pistons. Jag is well aware of this issue. The dealer may not be. In my case, even though the car was 6 months out of warranty, they chose to do a free engine replacement. Get the bore scope work done.

 

We've missed you - welcome back!

 

appreciate the welcome. Have been obsessing over my FJ40 restomod project. Front and rear air lockers going in this week.