Hello to the forum. Please, accept in advance my apologies for the lengthy post, but I want to be as thorough as possible.

I retrofitted cruise control to my Stilo 1.2 almost six weeks ago. I found a cc stalk from an Alfa 147. The wiring from the steering column to the battery bay was already set, so I just screwed the stalk onto the column, connected its plug to the afformentioned one and connected the wires in the battery bay to the correct holes on the ecu plug. The cruise control worked and everything seemed to be alright. Alas...

A few days later I had an engine failure message and the orange engine dash icon/light on. It went away after a few minutes, so I attributed it to a random/false alarm reading of a sensor.

But, it kept happening at an accelerating rate and not only that, but I started experiencing throttle acceleration problems, lack in engine power and at times sudden engine stallings. The problem just kept worsening, to the point that the car was not "drivable" anymore, so I went to the local FIAT dealership, and the diagnostics showed throttle body damage.

It just so happened that there was a brand new throttle body available, so I had mine replaced with it in order to check whether this was indeed the problem or not. The car worked properly for about a week before the same engine failures started again... The car also had great difficulty in engine starting, as if the battery or the petrol was bad...

The next thing we tried was a whole set of ecu-body computer-immobilizer-key we got from another 1.2 stilo, just to eliminate any possibilities.

It just took me 10 meters with the new set for the engine failure warning to show up... . Of course I had my ecu-bc etc back on the car and I left it there to give the mechanics time to investigate it.

Finally, they unplugged the cruise control cables from the ECU plug and the problem just disappeared! And now the car starts its engine in the blink of an eye!

One would ask, "why the hell didn't you just try it in the first place?"

Well, the thing is that I had had some of those symptoms again, almost 3 months ago and back then the problem had been improper ground wiring of the LPG system of the car. Also, the cruise control worked properly, so I did not think it could have been the source of the problem. My bad.

The thing is, I cannot understand, why on earth does it cause this kind of problem. One thing I did not like is that I measured the cc voltage line and it was 13.9V instead of 12V... The only explanation I can give, is that these 2 exta volts screw up the ecu operation and that could also explain the throttle body's erratic behaviour.

Could this be the case? Does any from those who retofitted cc know what the correct voltage should be or how many volts they have on their cc voltage line?

Any help is more than welcome!

I measure the Voltage line via obd2 adapter and its from 12.5v when the car is not running and it goes till 13.8v when its running and all electric parts are not used.

Έλα ρε Νικηφόρε, μαζί είχαμε μιλήσει στο stiloclub και με είχες βοηθήσει στην εγκατάσταση! Όλα καλά; Τελικά δεν είναι το cruise control... Συνεχίζω στα αγγλικά παρακάτω, μη μας σβήσουν κανένα σχόλιο...

It seems the final word had not been spoken... Today, during a 100km trip to my sister the car started jerking and only minutes later the "engine falure" warning was on my screen along with the corresponding light... I managed to get back home and tomorrow I am heading back to the dealership for further examination.

The engine feels like it has lost half its horsepower and it's shaking on idle and low rpm as if it's running on only 3 out of 4 cylinders, but it's probably the usual "throttle body sensor" problem. Which definitely exculpates the cruise control voltage line and leaves (at least in my humble opinion) the LPG system as the only remaining culprit (as it had been again in the past).
But that remains to be seen...