Technical Poor Idling, does the 1.2 Lounge 2012 have an IAC ?

[Cerazy]

Hi all, I've a Fiat 500, 1.2 lounge 2012 (Euro5). Idle is poor as can be heard in video. As the engine RPM drops, the butterfly opens as if it's gasping for air. It's very regular and the engine RPM is about 800.

Changed the spark plugs, battery, ignition coil, unmounted and cleaned the butterly. No apparent cracks on the air hose pipes and earth cable look ok. There's some sensor under the butterfly gasket that feeds into the main air pipe but not sure if that's the IAC (?) and doesn't look easy to take out.

Any hints what I should examine in more details or look for next ?

Thanks a lot for any ideas

 

[steveras57]

Hi all, I've a Fiat 500, 1.2 lounge 2012 (Euro5). Idle is poor as can be heard in video. As the engine RPM drops, the butterfly opens as if it's gasping for air. It's very regular and the engine RPM is about 800.

Changed the spark plugs, battery, ignition coil, unmounted and cleaned the butterly. No apparent cracks on the air hose pipes and earth cable look ok. There's some sensor under the butterfly gasket that feeds into the main air pipe but not sure if that's the IAC (?) and doesn't look easy to take out.

Any hints what I should examine in more details or look for next ?

Thanks a lot for any ideas

The I A C is part of the throttle body!.
Have you removed the air filter box to see if it needs cleaning?.
If you run the motor with the air box off you might see the butterfly opening and closing as the ecu tries to balance the values!.
Check all the pipes/hoses for leaks and /or being clogged with gunk !,dont forget the small hose that runs under the air box!.
If after cleaning the throttle body( make sure to use a proper cleaner not carb spray or wd 40! )its till doing it then a used replacement might be a good idea?.
If you fit one it might need a proxi alignment via MES software to be sure its linked to the ecu properly!- it WILL need the throttle re-learn procedure doing!.
good luck with sorting this!.
Steve

 

[Cerazy]

Ah that figures for the IAC, thanks!

Yes I completely removed the air filter box and the filter is very recent. I get the same sound when the airfilter box is completely removed.

When the car is in idle, the butterfly is primarily closed and then opens/closes for a second when the engine rev changes.

I'll make a new movie without the air filter box attached.

 

[steveras57]

Ah that figures for the IAC, thanks!

Yes I completely removed the air filter box and the filter is very recent. I get the same sound when the airfilter box is completely removed.

When the car is in idle, the butterfly is primarily closed and then opens/closes for a second when the engine rev changes.

I'll make a new movie without the air filter box attached.

Above still applies clean the throttle body and hoses out if no better change it! and see what happens!

 

[Cerazy]

I didn't see any visible dirt on the hose endpoints but I'll inspect them more thoroughly ... Here' a vid without the air filter box. The butterfly enters this idle cycle after 1-2 minutes.

I'll change the "earth" cable anyway I read so many things about that one.

 

[steveras57]

I didn't see any visible dirt on the hose endpoints but I'll inspect them more thoroughly ... Here' a vid without the air filter box. The butterfly enters this idle cycle after 1-2 minutes.

I'll change the "earth" cable anyway I read so many things about that one.

To be honest its not moving as much or as often as mine did when i had a problem -mine was cycling ever few seconds!, also body looks relatively clean to me!.
Do you have mes software to do a throttle position re-learn? there does not appear to be anyone on the register in Belgium nearest is in the Netherlands towns of Roggel or Nuenen

 

[Cerazy]

Ah, I just have a OBD reader which reports error codes and a few live readings... i'll probably need to download an iPad app or go to the garage to perform such a throttle re-learning

 

[Cerazy]

Couldn't find anything visually wrong so I called on an electrician who traced an issue with the oxygen sensor. Car is definitely more responsive than before and the idling has basically gone. I'll see how things go in the current days.

I hindsight, I should have started by cleaning all sensors & butterfly, replace air intake pipes and earth cables, a dose of injector cleaner ... and then investigate deeper.

I'll report back

 

[steveras57]

We will be waiting!

 

[Cerazy]

Well my issue persists. I seem to have the same symptoms as another poster https://www.fiatforum.com/threads/engine-chokes-every-few-seconds-while-radiator-fan-on.481660/

Sometimes the idle is good but when you apply a high electrical load, I get a poor idle. I managed to play with a high load (max fan for hot air) to force a bad idle and then switch it off to allow the idle go back to normal !

• I changed battery, oxygen sensor, ignition coil, temperature sensor (due to leak)
• I removed and cleaned the MAP sensor and throttle valve
• I put some good engine cleaning additive (Marly 1.5L can)
• Inspected air intake pipes and air filter
• Added a new earth strap in parallel to old one.

So far 2 independent electricians couldn't find the issue, for them the voltage readings of the alternator are all good.

I think I'll bring it to Fiat as I am running out of ideas.

Cheers

 

[Cerazy]

Finally got an appointment with Fiat ... total disappointment as they said my car was normal. All diagnostic parameters were normal.

In the mean time my ELM327 reader and A3 cable arrived. Bought the multiecuscan and noted that the 'Spark advance' would jump from negative to positive. I did two throttle valve re-learning and reset the self-learned ecu parameters....BINGO!

If only a working OBD2 reader had arrived much earlier.

So far so good.

 

[steveras57]

Why the hell didnt the dealer consider it might need those re-sets then!

 

[John202020]

Why the hell didnt the dealer consider it might need those re-sets then!

I guess their diagnostics parameters didn't include ones that actually control the engine?

 

[Cerazy]

I actually gave them a sheet describing what I did and suggested an ECU reset ... I was told I would have to go to the original dealer that sold the car for the reset. It's a big dealer, can't believe they wouldn't have the tools to make a reset, either they just ignored my sheet or just too lazy.

Now I need to resolve the knock-on effects of the reset: pedal issue