Hi all,
Does anybody know what actually happens to the engine management and controls when we get the dreaded "restricted performance " flag up, I would like to know say, how the rev limit is xxxxx, is the fueling sequenced between cylinders ( in case you have a leaky injector) does the lambda sensors go into loop mode, does the throttle body have restricted movement? these are the things that I would like to know and I cannot seem to find any reference on line, surely someone out there must know or have a good idea about it.
hoping that there is information available.
Thank's lads and lassy's
rrosscoe

 

Download and install the JTIS (in the stickies), when viewing you MY read the specifications area for fuel and power train. Also in stickies I believe is the engine rebuild / class doc this maybe helpful also (might also be found in large file area ;-)

 

Don't know exactly what car i.e. what PCM you have but mine is defending the car from damage bearing in mind it's found sensor value(s) it knows are weird - maybe including voltage(s).

You can pretty much guess what a PCM in distress must do to try to run an engine with a weird set of signals and I don't recall it being detailed anywhere. By way of very obvious example it will try hard to avoid running lean. Similarly, it will try not to kill the cats. Etc.

It's entirely possible that as Jaguar learned more they tweaked the software so it's going to matter what you have in your PCM...

Without the software and/or its design documentation we'll be guessing and Jaguar are not going to release those.

 

Hi JagV8,
just checked my profile and I have included a picture and description of my car but it never seems to show it when I post?

 

You need to put the info in your signature through your control panel.

 

Are you posting by phone?. I have found signature does not display when posting from my phone but is displayed when posting from PC.

 

He doesn't have a signature.

 

Found CP and edited it with description and photo but doesn't seem to work still, unless I have to log out and then back in again?

 

Yahay it does work just shows that you should read the instructions EH!
rrosscoe

 

The rev limiter is 3,000 rpm. You will know when you bump it as it rather dramatic and will get your attention. Don't remember exactly why but been there.

 

Yahay indeed

In rough detail, the PCM can run an engine crudely (OL - open loop) or in a sophisticated (CL - closed loop) manner. To do the latter it needs to see sensors that appear working - actuators also. The more recent PCMs get faster CPUs, more memory, etc, so have better ways of coping. I'm doubtful any car maker will reveal all the details, especially as they change them if they figure anything new.

OL it basically needs to know the O2 and can add fuel. Aims for rich.

CL and it's along these lines OnBoardDiagnostics.com - Engine Basics

http://www.thejagwrangler.com/upload...management.pdf

So... RP is (probably?) somewhere in between. Some sensor(s) look wacky. Maybe an actuator looks odd, via a sensor. The PCM has a go at coping instead of disabling the engine and shutting down leaving you stranded.