Technical Help! Rough Idle and Stalling.

[Fiat500Fiat500Fiat500]

Hi, new member here, nice to meet y'all.

Car started to have inconsistent idling, when the car is idling the sound it makes goes up and down every few seconds.

I have installed a new throttle body, new spark plugs and a new MAF sensor, however the car has improved ever so slightly but still stalls after a while.

Airbox is in good condition and the air filter is new.

When installing the new throttle body I noticed there was some oil inside the air intake manifold and also inside the MAF sensor hole. Please see image for reference below.

The car does not provide any fault codes on the OBD reader.

If anyone has any advice or experience with this, please let me know.

Fiat 500 312 1.2 Petrol 69 hp / 51 kW 2007 - 2025 169 A4.000

Thanks for yout time in advance! Much appreciated.

 

[The Panda Nut]

Definitely clean this out. I have fitted catch cans to ours which eliminates this oil getting through. I used clean rag attached to a thick wire it improved mine. Change the plugs too, they dont seem to last long. Next stop is injectors. Plugging in to MES might help. Some on here in the Mes register may help.
I had an issue like yours. I ended up doing plugs, leads coilpack and cleaning throttle body and manifold. New throttle body may require ECU relearning / proxi alignment.It was fine after but I have no idea what item fixed it. Sorry.

 

[Mike1alike]

Hi an welcome to the forum!

Car started to have inconsistent idling, when the car is idling the sound it makes goes up and down every few seconds

How much up and down does it go? Is the RPM gauge's needle moving? Watch exactly what values it moves around if it does. Does it go up above idle RPM and comes back or below idle RPM and comes back?
Did you do some work on the engine before this happening or did the problem just popped up?
There is a lot of oil inside intake manifold. That is a common problem on Fiat cars. Do clean it. The reason for that happening might be clogged oil line inside rocker cover. That line feeds oil to the camshaft bearings and should splash good amount of oil on the engine's upper part. If there is improper lubrication those parts get heated and the little oil amount that comes in contact with the heated parts gets burned and excessive oil vapors result and they are traveling to the intake through breather.

 

[steveras57]

I had similar issues and tried the same things in the end i swapped the fuel injectors out and that cured it! as injectors wear the spray pattern changes and weakens thus the fuel does not burn properly hence the rough running!

 

[GettinBetter]

Stick a can of BG Products 44K in a full fuel tank, by the time you've used the tank, you should notice the difference.

I've used this product for years, and regularly do mine, and I keep a can on my shelf.
Do it before spending any serious money on injectors. IMO, it's a cost effective service.

 

[steveras57]

Stick a can of BG Products 44K in a full fuel tank, by the time you've used the tank, you should notice the difference.

I've used this product for years, and regularly do mine, and I keep a can on my shelf.
Do it before spending any serious money on injectors. IMO, it's a cost effective service.

Agreed! if it works.

 

[GettinBetter]

Agreed! if it works.

About. 12 years ago when I was building marine engines, the BG Products sales team came to my workshop, and demonstrated some of their products on our engines.
As an extreme skeptic, I was very impressed, but not totally. So over the next few weeks proceeded to add products to my bench running engines, and strip down after, to investigate results. After seeing with my own eyes, I was happy to continue using their chemicals.

 

[The Panda Nut]

Engine / injector cleaners are worth a try for sure I feel particularly for diesels . I do all ours annually, its cheap and unlikely to be harmful done as per instructions.

 

[steveras57]

About. 12 years ago when I was building marine engines, the BG Products sales team came to my workshop, and demonstrated some of their products on our engines.
As an extreme skeptic, I was very impressed, but not totally. So over the next few weeks proceeded to add products to my bench running engines, and strip down after, to investigate results. After seeing with my own eyes, I was happy to continue using their chemicals.

Wasnt saying it wouldnt work im a natural born sceptic the answer is to try it and if no improvement move on to substitution /replacement!

 

[GettinBetter]

Wasnt saying it wouldnt work im a natural born sceptic the answer is to try it and if no improvement move on to substitution /replacement!

Yes, I realize that, I was just adding some background as to my use of BG Products.