Hello everyone,
I am a Jaguar enthusiast and collector, who started-out with a 4.0 XK8, moved to a 4.0 XKR and finally landed on a 4.2 XKR.
As, after a repair, my XKR 4.2 SC started producing some undesirable noise from SC, which would switch engine to protection mode, I had it replaced with my old 4.0 SC, which I was keeping for spares.
Apparently, both SC’s look the same, that’s why we attempted switching.

However, engine protection mode kept on kicking in, whereas diagnostic read poor fuel (= excess air).

In order to solve problem, we replaced OGR valve, having no successful result.

At this point, we would be looking at some clarifying info as to whether superchargers for two models are same or different and as to feasibility of the swap: putting a 4.0 SC into a 4.2 SC car.

We would really appreciate any help and support.

Enrico

 

Did you eliminate the easy problems first? Excess air I assume means air leaks (P0171/4). Do a smoke test, there are so many opportunities for air leaks.

Can't help with suitability on the supercharger, apart from suggesting looking up part numbers, etc.

Best of luck, keep us posted.

 

The supercharger itself is interchangeable although the 4.2 has a newer version of the Eaton with some slight improvements.

Agree with fmertz though, if you are having “too much air” issues then an intake leak is the place to look first.

 

Hello guys,
these are the reassuring feedback I was hoping for.

We thought about checking air-leaks, but we wanted to make sure excess air was not due to charger, to avoid a useless waste of time.

Our doubts were somewhat confirmed by attached comments in an official paper, relating to improvements from 4.0 to 4.2:

 

The inlet of the superchargers with accompanying gasket is different, are you sure you have perfect fit there? Going from a 4.0 to 4.2 requires some small adjustments, there may not need to be made adjustments when going from a 4.2 (and 4.2 gasket) to a 4.0 SC. Nevertheless this is the 1st spot I would check for the an air leak

 

This is really helpful and it greatly simplifies our job!

Thanks a lot for the suggestion.