ATPS of 83.9%?

davidbooker · 25th July 2008, 12:06

I've just purchased one of RoverRon's superb OBD2 readers, and eagerly plugged it in. Although one of the VIS motors seems a bit noisy, absolutely no fault codes of any sort were shown.

However, the Absolute Throttle Position Sensor is showing only 83.9%. Is this normal, or am I potentially losing 16% power by not being able to open the throttle fully?

Is the cure simply a matter of adjusting the cable until it reaches 99.9%, or do I need a new throttle sensor?

Simon · 25th July 2008, 13:53

I'd say start with the easy thing first and try adjusting the throttle cable. Quite often there is some slack to be taken up. If that doesn't solve the problem then it may be the sensor but seeing as you're getting a reading from it then I doubt it's duffed up that much.

kaiser · 25th July 2008, 14:12

Get someone to press the pedal to the floor, then check if you can open the throttle body wider. If not, you are loosing nothing. If you can, adjust. Imagine if you get 15% more power than you are used to!! Somehow I doubt anyone could have been daft enough to leave that much slack, but who knows?.

Tatts · 25th July 2008, 15:47

Quote:

Originally Posted by davidbooker

I've just purchased one of RoverRon's superb OBD2 readers, and eagerly plugged it in. Although one of the VIS motors seems a bit noisy, absolutely no fault codes of any sort were shown.

However, the Absolute Throttle Position Sensor is showing only 83.9%. Is this normal, or am I potentially losing 16% power by not being able to open the throttle fully?

Is the cure simply a matter of adjusting the cable until it reaches 99.9%, or do I need a new throttle sensor?

I have a reader from Ron too, but I've never seen ATPS in the menu on it.

davidbooker · 26th July 2008, 10:01

Thanks for your replies.

I asked SWMBO to "push the pedal to the metal", and the throttle flap is at full deflection in the body, so no free lunch, I'm afraid!

I ran the car down to my independent garage, and the owner, Colin, linked up his £6000 diagnostic computer. This has car-specific programmes, rather than the generic OBD2 reading capability. It reported that the VIS power valve is inoperative, just as I had suspected. This was not picked up by my £50 reader.

This device is also able to interrogate each electronic device to elicit a reaction. On this test, the VIS balancer valves sounded as though they were working properly, but the power valve produced nothing but a feeble click. Colin whipped it out of the plenum, and it was obvious that the actuator was totally kaput. The internal manifold flap valve appeared to move freely, though, so a new VIS motor module should do the trick.

Also, my fan has not been operating at its low speed for some time, so I have been keeping a wary eye (ear) on the A/C compressor in stationary traffic. Colin's computer interrogated the fan, confirming the lack of low speed, but discovered that the medium speed is inoperative too! The fast speed is fine, so the engine is still being protected. These fans really are c***.....the car has only done 50k!

Tatts, the ATPS reading can be found under the main menu choice (3) "Live Data". You may have to scroll down to find it. Hope this helps!

Regards, David.

Tatts · 26th July 2008, 10:18

David, thanks I found it.

Like yours, mine reaches around 82% but there's no more throttle flap to move by hand.

Your comments about VIS Motors & fault codes. Last year I knew my vis motor wasn't working, there was no extra power surge and the car felt lethargic. It was due a service, so I went down to see Lates.

He put his code reader on and there was no faults logged. But, when he removed the motor and tried it on his Testbox, it proved the motor was kaput. Upon opening the motor, the small electric motor had detached from the PCB & was rattling about in the case! That vis motor was less than a year old and covered less than 8000 miles.

So, I guess that a fault code is not always logged in the ECU when they decide to stop working.

25th July 2008, 12:06	#1
davidbooker Gets stuck in '51 Rover 75 2.5 V6 Conn. Purchased 02/05 Join Date: Dec 2006 Location: Whitby Posts: 574 Thanks: 8 Thanked 33 Times in 22 Posts	ATPS of 83.9%? I've just purchased one of RoverRon's superb OBD2 readers, and eagerly plugged it in. Although one of the VIS motors seems a bit noisy, absolutely no fault codes of any sort were shown. However, the Absolute Throttle Position Sensor is showing only 83.9%. Is this normal, or am I potentially losing 16% power by not being able to open the throttle fully? Is the cure simply a matter of adjusting the cable until it reaches 99.9%, or do I need a new throttle sensor?

26th July 2008, 10:18	#6
Tatts This is my second home MG6 TL Join Date: Nov 2006 Location: Tarn Posts: 5,269 Thanks: 2 Thanked 46 Times in 37 Posts	David, thanks I found it. Like yours, mine reaches around 82% but there's no more throttle flap to move by hand. Your comments about VIS Motors & fault codes. Last year I knew my vis motor wasn't working, there was no extra power surge and the car felt lethargic. It was due a service, so I went down to see Lates. He put his code reader on and there was no faults logged. But, when he removed the motor and tried it on his Testbox, it proved the motor was kaput. Upon opening the motor, the small electric motor had detached from the PCB & was rattling about in the case! That vis motor was less than a year old and covered less than 8000 miles. So, I guess that a fault code is not always logged in the ECU when they decide to stop working. __________________ http://www.wcgsig.com/115562.gif

25th July 2008, 13:53	#2
Simon Banned - Join Date: Nov 2006 Location: - Posts: 10,318 Thanks: 0 Thanked 4 Times in 3 Posts	I'd say start with the easy thing first and try adjusting the throttle cable. Quite often there is some slack to be taken up. If that doesn't solve the problem then it may be the sensor but seeing as you're getting a reading from it then I doubt it's duffed up that much.

25th July 2008, 14:12	#3
kaiser This is my second home 75 Tourer 2.5 Auto, 1.8T, 75V8ZT Join Date: Jun 2007 Location: Johannesburg ZA Posts: 6,200 Thanks: 1 Thanked 859 Times in 613 Posts	Get someone to press the pedal to the floor, then check if you can open the throttle body wider. If not, you are loosing nothing. If you can, adjust. Imagine if you get 15% more power than you are used to!! Somehow I doubt anyone could have been daft enough to leave that much slack, but who knows?.

26th July 2008, 10:01	#5
davidbooker Gets stuck in '51 Rover 75 2.5 V6 Conn. Purchased 02/05 Join Date: Dec 2006 Location: Whitby Posts: 574 Thanks: 8 Thanked 33 Times in 22 Posts	Thanks for your replies. I asked SWMBO to "push the pedal to the metal", and the throttle flap is at full deflection in the body, so no free lunch, I'm afraid! I ran the car down to my independent garage, and the owner, Colin, linked up his £6000 diagnostic computer. This has car-specific programmes, rather than the generic OBD2 reading capability. It reported that the VIS power valve is inoperative, just as I had suspected. This was not picked up by my £50 reader. This device is also able to interrogate each electronic device to elicit a reaction. On this test, the VIS balancer valves sounded as though they were working properly, but the power valve produced nothing but a feeble click. Colin whipped it out of the plenum, and it was obvious that the actuator was totally kaput. The internal manifold flap valve appeared to move freely, though, so a new VIS motor module should do the trick. Also, my fan has not been operating at its low speed for some time, so I have been keeping a wary eye (ear) on the A/C compressor in stationary traffic. Colin's computer interrogated the fan, confirming the lack of low speed, but discovered that the medium speed is inoperative too! The fast speed is fine, so the engine is still being protected. These fans really are c***.....the car has only done 50k! Tatts, the ATPS reading can be found under the main menu choice (3) "Live Data". You may have to scroll down to find it. Hope this helps! Regards, David.