Hi All

My Ritmo (Im in Aust) has 105 000 km on it and has started to do the following on cold start up-
Engine cranks fine but is rough and sounds like its misfiring/about to stall for 5-8 seconds then corrects itself when choke comes on? I have a video but it wont upload - any ideas? This only happens on the first start up of the day.
Thanks in advance ?

Use all fuel in tank, beyond "0 km/miles left" message on display

Pour fresh fuel.
It should be fine then for a while.

Some say that replacing pre-cat oxygen sensor may help.
I have same issues, and always when i pour fresh fuel, simptoms dissapear for a 2-3 weeks

I will also try replacing oxygen sensor.

MikeG20 said:

Use all fuel in tank, beyond "0 km/miles left" message on display

Pour fresh fuel.
It should be fine then for a while.

Some say that replacing pre-cat oxygen sensor may help.
I have same issues, and always when i pour fresh fuel, simptoms dissapear for a 2-3 weeks

I will also try replacing oxygen sensor.

Click to expand...

Won't help, i've replaced the O2 sensor.

I'm experiencing similar issue and I figured out that when cranking, I step a bit on gas and it starts much much better.

Myhotpunto said:

Hi All



My Ritmo (Im in Aust) has 105 000 km on it and has started to do the following on cold start up-

Engine cranks fine but is rough and sounds like its misfiring/about to stall for 5-8 seconds then corrects itself when choke comes on? I have a video but it wont upload - any ideas? This only happens on the first start up of the day.

Thanks in advance [emoji3]

Click to expand...

Got the same thing. It’s normal I’m told.
Problem solves with full tank of 98 octane fuel.
Mine does it when there’s less than 1/3 tank and especially on colder mornings. [emoji106]

Ive dropped to 95 oct fuel and had injectors cleaned all good now

I had the same problem. But i start to fill up with 98 -100 oct fuel.
With good octane fuel, all problems disappeared.

I still think that most of cold start problem on T-JET - is on a ECU software issue, when you have some old fuel - t-jet won't start from 1st attempt, but other cars starts on that fuel well.
(If someone have opportunity and desire - go to the fiat official dealer and ask about new software versions with bug-fixes)

Hi, had the problem for a few years now, 1 month ago I´ve fixed a cracked exhaust manifold and turbo exhaust snail, problem gone, start at first since, I thing the lambdas sensors miss read the mix air/fuel with the exhaust leak.

you should check both, my manifold had several small leaks and the turbo was crackr«ed from the wastegate to the exhaust turbine, engine always pulled right even with my 1200kg caravan.

Mgasp said:

Hi, had the problem for a few years now, 1 month ago I´ve fixed a cracked exhaust manifold and turbo exhaust snail, problem gone, start at first since, I thing the lambdas sensors miss read the mix air/fuel with the exhaust leak.

Click to expand...

what does oxygen sensors have to do with cold start ? especially if the corrections are normal.

well, they read the air/fuel ratio from exhaust to tune to optimal burn, if theres a leak somewhere the exhaust, it cause a o2 entry and get them to missread the exhaust gas value, and so the air/fuel mix ratio gets wrong and can cause bad start, change off power with high polution level for mot etc...
the intake and exhaust must be 100% air leak free for optimal burn, lambda value etc...

Mgasp said:

well, they read the air/fuel ratio from exhaust to tune to optimal burn, if theres a leak somewhere the exhaust, it cause a o2 ...

Click to expand...

I will disappoint you, but Oxygen sensor stars work after ~300C, so in cold start it do exactly nothing

wrong, thats why it got an internal heater, its only the 2nd sensor that work after engine heated, the precat works since start to adjust mix.

Mgasp said:

wrong, thats why it got an internal heater, its only the 2nd sensor that work after engine heated, the precat works since start to adjust mix.

Click to expand...

Actually it takes a few minutes from a cold start for the ecu to go into closed loop and start using the precat o2 sensor to adjust the fuel air mixture even with a built in heater.