Hi,
finally getting my Xkr together again, today working with the TB. Had it apart some time ago but today I reacted when "testing" the butterfly opening whilst rotating the lever normally operated by the cable from the gas pedal. With the rotating lever fully operated the butterfly valve only opens about 30 degrees but that is normal? The rest will be done by the motor?

Found this in a 1999 workshop manual but not sure if i applies to 2000 year model Xkr:

Throttle Body
The main features of the motorised throttle body are:
Fully motorised control of the throttle valve from the ECM.
The throttle valve is coupled to a dc motor via reduction gears and quadrant and is positively driven by the
engine management system between the fully closed and fully open positions, in both directions, without
any intervening mechanisms, ie it is a 'full authority' system. A twin potentiometer sensor on the motor end
of the throttle shaft provides direct feedback of the actual valve angle to the EMS and is similar to the
throttle position sensor in operation.
Mechanical, cable operated 'limp home' mode with restricted throttle opening.
The limp home mechanism consists of the accelerator input shaft link lever and the two throttle shaft
levers, all three levers being interlocked for limp home operation. If a failure in the throttle mechanism or
control system results in the engine management system selecting the limp home mode, motor power is
cut by de-energising the motor supply relay and/or by de-activating the PWM motor control signal. In limp
home mode, the throttle valve is operated mechanically from the drivers pedal and throttle opening is
restricted to a range from idle to a maximum of approximately 30 degrees

 

H,
Key out, butterfly (b) valve should be closed.
Zero slack in throttle cable.
OBDII plugged in, depress gas pedal all the way, obdii should show 100% throttle.

Hope this helps, John

 

Thank you for the explanation John.

What considers me at this point is how it should behave before I mount it in place. It worries me I might have got it assembled in the wrong way.

Recorded a short video of how it behaves now, operated by hand

The butterfly is completely closed. The lever first travels a bit only against the springs, no movement of the butterfly.

Second phase is when I rotate the lever further and the butterfly opens, approx 30 degrees. No further rotation of lever is possible from this point.

 

That is correct! It only opens about 30 degree mechanical. This is a drive by wire system. You have to connect the electrical motor in the throttle body to the cars ECU an turn on the ignition before you test it.

 

And it is the same for all different setups, Xk8 until 2002, Xkr until 2002 and the setup with the AJ34 from 2003?

 

No. The pre-99 AJ26 is 'limited-authority', i.e. the electronics doesn't have full control over the throttle position.

The Jaguar Training Manual 881 explains the differences between the two, although I had to read it more than once to get my head around the concepts. Available here on Gus' site:
http://www.jagrepair.com/images/Trai...ual-9-5-01.pdf

 

From what I can remember (its some time ago though) the AJ26 TB would open fully mechanically, though the ECU can throttle it back, so I guess you have not put it together correctly. So when fully open it via the cable you can push the blade back by hand.
(AJ27 and newer are full electronically controlled).

 

Mine is a 2000 year model AJ27, should have mentioned that

 

Then I think you are good ;-), I can remember now you mention its an AJ27, that although that one is fully electronically controlled, there is still some movement available which you show. That is for emergency use, where in that situation you can control more airflow, but the ECU would still control the rpm of the engine via the fuel flow.

 

Thanks for the confirmation
Makes me happy that I can move on to the next stuff on the long list of items to be mounted back to the car

Supercharger
Intake elbow
Charge coolers/intakes
Air inlet pipe
MAF
Rear hubs and brakes