Mk6 fiesta wont idle

[GLM]

Hi there, just another quick update. I've got the lead from the company you recommended. Plugged into forscan. Had a few DTCs. Cleared those and reset all adaptions etc. Definitely worked as the car runs a bit strange now that it's learning all the new values. Unfortunately I'm not able to actually interpret the data properly as I don't know what certain values should be compared to what they are.

The codes I had recorded are attached.

I cleared these reset all adaptions and run the car and only 1 came back again. 

 The fuel system enters 'closed loop' mode after about a minute from engine start. The upstream oxygen sensor voltage fly's up and down all over the place where as the downstream sensor stays steady at 0.45-0.65. I have no idea of that is normal.

Is there any way you could enlighten me on a few live data results I should look out for and how to tell if they're telling me something is wrong ie, MAP sensor, sparkadvance, O2S11 and O2S12 (oxygen sensors). 

Is there a way I can send you my life data report that I've saved?

Failing this I think it will have to go into a dealership and I'll just have to swallow my pride.

Thanks,

George

[Tdci-Peter]

On 5/11/2019 at 9:07 PM, GLM said:

I cleared these reset all adaptions and run the car and only 1 came back again. 

 The fuel system enters 'closed loop' mode after about a minute from engine start. The upstream oxygen sensor voltage fly's up and down all over the place where as the downstream sensor stays steady at 0.45-0.65. I have no idea of that is normal.

Is there any way you could enlighten me on a few live data results I should look out for and how to tell if they're telling me something is wrong ie, MAP sensor, sparkadvance, O2S11 and O2S12 (oxygen sensors). 

Is there a way I can send you my life data report that I've saved?

Interpreting live data from a modern petrol engine is uncomfortably close to my limits of understanding. Interpreting life data from a fellow human would be way, way beyond my limits 😁.

So it does report a problem from that Evap valve, but if it was disconnected at any time while the ignition was on, that could be the cause. Baro seems to be basically just the MAP (manifold pressure) sensor, I guess it senses atmospheric pressure while the ign is on but the engine is not running. IAT is also part of the MAP sensor, it looks to be a T-MAP sensor on these engines, with 4 pins (Vref, Gnd, MAP signal, NTC signal).

I am not clear which one returned immediately, this one would be a prime suspect for a problem area.

Upstream O2 sensor should vary in a regular way, but when combined with the rather irregular sampling of Forscan, it may look a bit random. Not the fault of Forscan, it has to compete with all the other engine modules for time slots on the CAN bus, and is probably given lowest priority. Downstream O2 should be much more constant if the cat is doing its job.

The Forscan .FSL files can be posted on this site if they are renamed as .TXT files. If there is still a problem, Forscan can save them as .CSV files, there is an option in the save file menu. Then these can be renamed as .TXT files, and they really are just text files with no funny binary characters that may alarm some sensitive computer systems. I can read either .FSL or .CSV files..

Being able to read them is one thing, determining what is wrong is another. But it is worth a try.

Since having Forscan, I have taken occasional logs of my car, when it seems to be running ok. The idea is that this gives me a baseline to compare to if things start to go pear shaped. But in general, neither the opportunity nor the motive will be present before something does go wrong. I only downloaded Forscan after my car had gone disastrously wrong, with me having no real idea of why!

The minimum data needed would be rpm, accelerator position (APP), MAP, IAT, O2S11 (or similar), O2S12. A run with some constant load cruising, some full power, and quite a bit of idling (as that is where the problem seems to be) might be the best.

[Ste Cooper]

I know this is an old thread now but is there a resolution either way?

Did you go dealers or manage to get it sorted?

Experiencing the same behaviour after an engine swap.

Ta 

[Tdci-Peter]

On 8/24/2019 at 5:26 PM, Ste Cooper said:

Experiencing the same behaviour after an engine swap.

Have you tried the throttle initialisation:

 

[Ste Cooper]

On 8/25/2019 at 11:55 PM, Tdci-Peter said:

Have you tried the throttle initialisation:

 

No i hadn't, didnt even consider that to be honest.

 

Sadly she's now in the car park in the sky so a bit a mute point but thanks anyway!