No Throttle Response after sitting on a Hill

[imck]

2008 Mazda 6 2.5 Petrol

Sat on a Hill waiting to pull out after queuing in Traffic.
No or very little response from the Throttle when attempting to pull away.
No/little response when revving in Neutral. 10-20 Seconds it will rev again and I can pull away.

This has happened 3 Times in the last few Weeks. Always after queuing on an incline.

Serviced October Last Year.(I do 8K Miles/Year) Not sure if Fuel Filter was replaced.
I have a bit of hesitation when crawling in traffic and a slight 'hiccup' around 3K RPM.
I cleaned the Throttle Body 6+ Months ago. This has only been happening in the last few Weeks.

Any Theories/ideas please?

[imck]

Yes. Not getting an Engine Light on the Dash though.

[imck]

I have a Bluetooth ELM327. Arrived Today and I have downloaded Torque Pro.
Bought for the Mrs Yaris which has just had the Engine Light come on !!

I see what you are saying about the TPS but odd that it only happens on Hills.
I was wondering if some sort of fuel starvation?

[imck]

Plenty of fuel in the Tank.

Up Hill only. On all occasions after sitting stationary at idle for a minute or more.

[imck]

E-bmw said:

Doesn't mean you don't have anything "pending" get it read just in case.

My new OBD2 Reader is not showing any faults.
I think I have set it up to log as I drive. Will see if that produces anything meaningful.
I might find a quiet Hill to sit on to reproduce the symptom. Was not fun trying to get onto a busy Roundabout this Morning.

[imck]

Happened again Yesterday. Same place. Sitting in a queue going uphill after approx 30 Mins from Cold Start.

Torque Pro Logs show the Input from the Pedal Sensors increasing but no corresponding increase on the Throttle Position Sensors.

I would appreciate someone having a look at the Torque Pro Log.
I have made it more readable and highlighted the 7 Rows where the error happens.

Link to Spreadsheet on my One Drive
https://1drv.ms/x/s!AtCz6AtB1md4gY8YP9nzJXdfl3BFoA

Thanks

[imck]

Drive by Wire

[imck]

The values in the Log for both the PPS and TPS are %

At Idle
Accelerator Pedal Position D 15%
Accelerator Pedal Position E 7%
Relative Throttle Position 2%
Throttle Position Manifold 11%

Steady 50MPH 2K Revs
Accelerator Pedal Position D 24%
Accelerator Pedal Position E 12%
Relative Throttle Position 9%
Throttle Position Manifold 18%

When the Fault occured. (I kept pushing the Pedal downwards)
Accelerator Pedal Position D 34%
Accelerator Pedal Position E 16%
Relative Throttle Position 3%
Throttle Position Manifold 12%

There is a Forscan App available that is supposed to work with my OBD

[imck]

When the fault occurs the Pedal compared to the Throttle values do not seem consistent to me.
The Pedal % Increases but the Throttle % doesn't.
I would also expect to see an error if the ECU does not see an expected Throttle response. Very odd and annoying.

It does have Traction Control (DSC). A warning light appears when it activates. No Snow Mode. Manual Gearbox.

It is very intermittent. 4 Times in the last Month or so.
Twice when giving someone a lift for a Week and sitting uphill at the same Traffic Lights.
Twice after coming up the same Motorway Slip Road and queuing on my usual Route to Work. (15 Miles/30-40 Mins)
I don't know if the Hill is a red Herring or just where I happened to be sitting at idle and not moving for some time.

The Ford/Mazda Forscan App does not work very well with my Bluetooth OBD2 Device. Connects but can't get any Data out of it.
My next step is to get something that will run Forscan.

[imck]

Thanks for the Ideas.

I work in Electro-Mechanical Repair and usually quite good with Logic.
This just doesn't make sense !!

I had considered replacing the Throttle Body and MAF. Not cheap Parts to throw at it though.
It can be quite jerky in crawling Traffic and there is some hesitation/hiccup at certain Revs.

One of my Colleagues suggested Breather System? I was giving him a lift for a Week and he said he had noticed some Hesitation.
There are some guides/videos for changing the PCV. Intake needs to come off. No idea if this would cause any of the Symptoms I have got?

I can't find a Service Manual apart from a scanned Russian one.

Getting a bit fed up with the Car
The AC only cools for around 30 Mins. Hopefully a regas and Drier might fix that. Suspect moisture/icing
The Wheels need a refurb and new Tyres.
Bought in the Rain and didn't notice a badly touched in scrape down the Side.
Do I spend or move on.

I will order an OBD Adaptor that is compatible with Forscan and see if that gives any more clues.

I might well be interested in the Throttle Body and MAF.
Presuming you are not scrapping due to yours also being an arse

[imck]

GreenV8S said:

That's consistent in that both pedal position sensors show readings consistent with the physical position, and the throttle pot position sensor confirms that the throttle is closed, which is consistent with the lack of power. That suggests that these sensors are working correctly and the problem is that the ECU is not opening the throttle. The lack of fault codes suggests it is not even trying.

I'm assuming here that the ECU provides a fault code for the throttle actuator.

Since I don't understand the mechanisms causing the problem, I'd be inclined (sorry) to try to get more information about what provokes it. Is the slope significant, or just a coincidence that the times you are stationary during your regular drive just happen to be on a hill?

That makes good sense Thanks.

If Pedal Pressed and Fuel Pressure (for example) Sufficient, the ECU opens the Throttle.
If not, the Throttle is not opened.

[imck]

I have found an English Service Manual and have downloaded.
https://drive.google.com/file/d/0B6ixeaKldj3rVW9Sc...
Page 1133

Very apt Statement in the Manual....
The PID/DATA MONITOR function monitors the calculated value of the input/output signals in the PCM.
Therefore, an output device malfunction is not directly indicated as a malfunction of the monitored value for the output device.
If a monitored value of an output device is out of specification, inspect the monitored value of the input device related to the output control.

Yes. the CEL is working.

There are some reference values in the Manual. The Pedal and TPS values I captured with Torque match them.
I think I need to expand what Functions I am monitoring.
The Forscan App has unit options. Voltage, etc rather than % Values.

I really appreciate your ideas and suggestions. It has made me think about this differently.
Cheers

[imck]

My New OBD Adapter turned up Today
Used with Forscan. Excellent bit of Software. Can do all sorts with it on my Windows 8.1 Tablet.
Multiple Systems can be monitored including the Brake and Clutch Switches.

It showed an Error Code which does not cause the CEL to come on.
U0140 Lost Communication with Body Module
No indication of when it appeared. I did disconnect the Battery when cleaning the Throttle Body 6+ Months ago.
Cleared along with TPMS Errors (Sensors are on my Bench at Home waiting new Batteries and Valves rather in the Wheels)

The position of the OBD Socket and size of the Adapter means it is a bit too close to my Right Foot to drive safely with it plugged in.
Have ordered an OBD extension Cable.