My Stilo (1.6) has developed some sort of disease, and I am struggling to find out what it is.

First:
For many months now, perhaps almost a year (as I didn't quite notice), the engine temp has never been on top for long, before it falls one "notch" and then pretty fast climbs up again. Usually it will stay just between top and the notch to the left. It never overheats, so thats's alright. The coolant is under 2 years, and not a drop is lost.

Second:
A couple of months ago, a coil said goodbye, and was changed. FES stated a faulty injector, but this moved along with the faulty coil as I did a swap test. Two weeks later, a new coil went, but in the meanwhile I had ordered a new set of 4. So I changed all to the new set, keeping the first change as a spare (again). Then it was alright again, with no faults.

Third:
The car has used more fuel than usual. Not in city driving, but on long trips, perhaps 20% more. It also smells gasoline on startup, and excess smoke when the car idles - and very cold outside. It does not use any oil.

Fourth:
The car has (since around the coil change) had a little lump / jerk, barely noticeable when doing this: Giving full throttle in high gear, with too high gear, lets say you drive in 60 km/h (45 mph), the road is almost flat, and you gear up from 4th to 5th - then when you hit the pedal it produces a small jerk. Not after, just when you hit the gas.

Fifth:
Engine does not sound too healthy, but that might be just me. It idles nicely, but sounds a bit rough.

Sixth:
Yesterday the jerk happened again, and the engine light came on. "Engine management control failure, return to dealer" or something like that. Hooked up FES and I got p0203, injector fault on cylinder 3. Cleared the fault, and haven'd done anything more as it was cold, dark and late.

Before I get any not-so-great ideas, I was hoping someone else could give me some starter-clues.

Morten.

Hmmm could be lots of things Morty. My suggestions:

Thermostat sticking?
Clean your throttle valve?
Clean your MAF sensor?
Crankshaft position sensor gap OK?
How long since you changed your plugs?

Morty I have the exact same problem (except the unsteady temp). My 1.6 started to jerk heavily when I pushed it more than 3000 rpm and the engine light would turn on - P0203.If I drove in granny style this only occured when I was going up a hill.
I checked the cables going to the coils and they seemed a bit loose so I used tie wraps to fasten them. This seems to fix it by 90%. I occasionally get the same jerk, especially when the engine is cold, but when the engine temp rises I get none.
It seems to be some sort of electrical problem but I haven't figured it out yet.
I also get quite noticable shaking when on idle although idle seems quite steady.
Is your throttle reaction smooth? Mine is not. When I press the gas the injectors seem to go boom and I start like Ayrton Senna and if I let my foot off the gas the injectors seem to cut down immediately making my girlfriend want to throw up....
This is not a throttle body problem because sometimes when I clean the electrical connections (throttle body, injector rail, lamda, fuse box etc) the car seems to drive super smooth, only to return to the previous state a few days later...

Got stuck at work...

Will try these things this evening.
- Check the injector main plug for circuit continuity.
- Clean the throttle body (though it is very rarely any dirt in it).
- Change plugs (they are 2 years old and need to be checked).
- Insert spare coil on cylinder 3.

Where is the map sensor, and what does it do?

Morty Mort said:

Where is the map sensor, and what does it do?

Click to expand...

It measures the volume of incoming air, so it will be in the pipework leading to the throttle (upstream). Look for an electrical connection on the inlet air trunking. Spray with contact cleaner.

Well, I carried out these things:
- Checked the injector main plug (male) for circuit continuity. They all showed around 14 ohms.
- Cleaned the throttle body, but it was in pretty good condition.
- Changed all plugs, but the old ones seemed to be good condition. Slight suntanned powder with no electrode wear. A bit sooty basering, so perhaps a too rich mixture.
- Changed coil on cylinder 3.

The car started nicely, but still sounded a bit rough. Consumption is still reading high, and the temp gauge still wanders around the top, but never above.

Will try it out some time, then check the MAP and then do the air filter.

Hello Morten old friend, wish I could help... I don't know that engine type.

MAP (Manifold Absolute Pressure) or MAF (Mass Air Flow) sensor?
If it's a MAF, mounted on the air filter housing, try unplugging it. The engine should run on default settings, so if it runs better, it means the MAF is faulty.

If it's a MAP, the pipe to it must be checked for splits/cracks or blockages.
I think the Weber-Marelli IAW system uses a MAP. But I don't know what system your engine has. I know my Stilo's 2.4 has a MAF (and no MAP).

I might be misinterpreting your original post, but it sounds like you had a fault code for a faulty injector. I'm not sure what triggers these injector fault codes - have you had the fault code since? Tried moving the injector to a different cylinder? Maybe it actually is a faulty injector? One injector not working probably means the engine runs lean and jerky.

-Alex

Yellow Peril said:

It measures the volume of incoming air, so it will be in the pipework leading to the throttle (upstream). Look for an electrical connection on the inlet air trunking. Spray with contact cleaner.

Click to expand...

I'm sorry to disagree, but you've described the MAF. That might be what's fitted to Morten's Stilo, so your advice is good - just the small difference in terminology to be aware of. And you did suggest the MAF in your original post, so I think you meant MAF

The MAP (if there is one) measures the vacuum in the inlet manifold (downstream of the throttle). On FIATs it is sometimes built into the ECU and is attached to the inlet manifold by a small rubber pipe (the size of windscreen washer tubing). Sometimes the sensor will be a separate box about 4cm square. Other times it may be mounted on the inlet manifold, though I haven't seen this. And I don't know for certain that the 1.6 has a MAP sensor because there are no 1.6 Stilos in NZ. This thread https://www.fiatforum.com/stilo/53702-engine-fault-stalling.html says it does.

-Alex

The 1.6 model has a MAP.