I have a 1998 Jaguar XJ8 and I'd like to know does it have a rev limiter?
I have read that it has a limiter for when its in park so you can't red line it but I can red line it in park or neutral.

If is supposed to be limited in park, can someone tell me what part does the limiting?

~Valiant

 

The XJR has the only rev limiter in P/N. It is 3000.

The XJ8 (N/A 4.0 cars) are limited to 7000 in all gears.
It can be revved to the limiter in P I believe. It is not
a good idea to rev an engine high under 0 load, let
alone to the 6,800 rpm redline.

For other users, it should be noted that the
RPM limiter is 6200 in the XJR, and 7000 in the 4.0.

The peak power delivered by the 4.0 N/A is at 6100.
so going to 7k is pointless. The XJR develops peak
power at 6150, as rated by Jaguar, which is deep in the
red.

Ian

 

Anyone used a piggyback to raise the rev limiter?

 

Where are the rpms when it shifts at full throttle? What would you propose to change the rev limiter to?

 

Thanks Ian, I understand it's not good for the engine. I'm trying to diagnose a problem, randomly it acts like its limited to 3K RPMS in all gears. That's why I was wondering about the limiter.

Does anyone know if the timing chain tensioners could cause the engine to do this?

Thanks again,
~Valiant

 

Well, a "restricted performance" warning light
will limit any XJ to 3000 RPM. Do you have any
orange (amber) warning messages?

 

Nope, no warning lights of any kind and no check engine codes.

~Valiant

 

You probably need to read 'live' OBD data since revving in P or N is not the same as when you're actually driving.

 

I've fixed it see my post here: https://www.jaguarforums.com/forum/x...52/#post571512