Throttle body
#1
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For some reason, my 2001 XJ8 has decided it doesn't want to accelerate. It will only make progress if the throttle pedal is slowly pressed. Any attempt at rapid acceleration leads to a lot of coughing and spitting.
I am old school as far as cars go, and despite this being my 4th Jaguar, I have never had this problem before. I had assumed that as in a carburettor, the throttle opened the butterfly on the XJ8 throttle body. This doesn't happen on this car. I have to assume now that it is an electrical function, controlled by a pedal position sensor and a motor somewhere.
Could someone help with this problem?
I have checked the air input and vacuum hoses and can find no leaks.
Thanks
Bill W
I am old school as far as cars go, and despite this being my 4th Jaguar, I have never had this problem before. I had assumed that as in a carburettor, the throttle opened the butterfly on the XJ8 throttle body. This doesn't happen on this car. I have to assume now that it is an electrical function, controlled by a pedal position sensor and a motor somewhere.
Could someone help with this problem?
I have checked the air input and vacuum hoses and can find no leaks.
Thanks
Bill W
#2
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The throttle position sensor (TPS) does provide signals to the engine control module (ECM) that operate a stepper motor attached to the throttle plate.
The TPS has long been a problem source and until recently replaced only with the entire throttle body as a substantial cost. Now there seems to be a couple sources for the sensor.
https://www.jaguarforums.com/forum/s...solved-138182/
Or you might try cleaning the sensor:
https://www.jaguarforums.com/forum/s...ics-faq-50741/
The stepper motor has also been a problem point.
I meant to add that if you have throttle body problems you should be getting a CEL and OBDII codes. ??????
The TPS has long been a problem source and until recently replaced only with the entire throttle body as a substantial cost. Now there seems to be a couple sources for the sensor.
https://www.jaguarforums.com/forum/s...solved-138182/
Or you might try cleaning the sensor:
https://www.jaguarforums.com/forum/s...ics-faq-50741/
The stepper motor has also been a problem point.
I meant to add that if you have throttle body problems you should be getting a CEL and OBDII codes. ??????
Last edited by test point; 04-22-2015 at 08:51 AM.
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Jhartz (04-22-2015)
#3
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Whilst I had the air cleaner/throttle body Air pipe off I thought I would check the MAF sensor. The sensor wires are difficult to see. After cleaning, they resembled what looks like a small resistor. The centre third seems to have small lump on it with the outside thirds being clean wire. There seems to be 2 of these ??.
Is what I see correct or should they just be clean wire from side to side??
Bill W
Is what I see correct or should they just be clean wire from side to side??
Bill W
#4
![Default](/forum/images/icons/icon1.gif)
Whilst I had the air cleaner/throttle body Air pipe off I thought I would check the MAF sensor. The sensor wires are difficult to see. After cleaning, they resembled what looks like a small resistor. The centre third seems to have small lump on it with the outside thirds being clean wire. There seems to be 2 of these ??.
Is what I see correct or should they just be clean wire from side to side??
Bill W
Is what I see correct or should they just be clean wire from side to side??
Bill W
If you have TPS or TPPS issues you'll know it by 'limp mode' not sluggish acceleration. The maf wires are as they should be.
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