Occational problem running on 3 cylinder getting a little worse. FIAT STILO (192) 1.6 16V (192_XB1A).

At every engine start, the stilo now feels like running on 3 cylinders. Starting to drive, about 1 km the engine goes back to normal / gets power back.. stopping at lights the engine sometimes goes back to 3 cylinders again. Sometimes at uphill it gets the engine warning on, beeping 4-7 times before the beep stops and engine light disappears.

The code started with:
P0301 - Misfire Cylinder 1

Then after a couple of deletes with the obd reader:
P0301 & P0300 - Random/Multiple Cylinder Misfire

Then once more:
P0301 & P0300 & P0203 - Cylinder 3 Injector Circuit Malfunction

P0203 only occured once after i drove on highway, starting with the engine light but no problems for 30km reaching home. It has now disappeared.

Done so fare:
- New coil in place of the original one in cylinder 1.
- Checked the spark-plug in cylinder 1, which seems normal (from 2015).
- Checked the resistance for all 4 injectors from the connector (all at 16.1ohm)
- Checked the voltage from the connector that feeds the injectors, with ignition on, all four at 3.6 volt.
- Swapped coil 3 & 4 just to test it. No difference..
- Tried to read voltage from battery minus pole to engine block, but reading 0.00 volt.

Reading from my OBD app, the o2 sensor nr.2 seems to go to 0 every time the engine runs on 3 cylinders. Also the fuel trims seems to fluctuate alot, going from a "normal idle" short term trim -60,9 to 37,5 when idling with 3 cylinders.

What should i do next`?
I am thinking about letting garage swopping two injectors, and let them make a compression test... But i also think there could be something wrong with the o2 sensor nr.2.
Any suggestions would be appreciated.

Thanks this awesome site.

So i was reading/ youtubing all day.. like a noob
And i came up with another to do list:

- Look for any vacuum leaks today or tomorrow with some carburator cleaner spray and engine running. Also checking the intake manifold gasket for leaks at cylinder 1.

- Check the signal to the ignition coils too. On the connection wires to the ignition coils with a multimeter.. reading should pulse between 0-12 volts with engine running. Test says to remove fuel-pump fuse.

- got some cheap parts from ebay (MAP sensor, and crankcase sensor), so might as well change them.

I will post the outcome

Looked for vacuum leaks today. The three vacuum hoses in the back of the air intake manifold are generally hard and can be moved a bit by hand with low force (see foto), will try to set some aluminium tape around the connections to the manifold.

Are there any other vacuum connections to check?

Also sprayed around carefully with engine start spray and specifically at manifold gasket, cyl.1. (see foto). No effect..

I noticed two nuts were missing at the exhaust connection, behind the exhaust cover, one at cylinder 1 and one at cylinder 4.. and two were loose. Cant supply the two missing yet, need to remove the cover first.

The engine since yesterday starts up fine, but once in a while it fells like goes to 3 cylinders for some minutes while engine shaking. Happens randomly.

So.. checked compression, 150 psi at all 4 cylinders. Changed spark plug gap tp be 0.8mm.. cleaned D4 connector again.. and the car is running a little bit better.. still getting the fault flashes though

Checked the OBD codes again, and two new ones had appeared:

P0638 Throttle Actuator Control Range/Performance (Bank 1) DTC
&
P1687, is an interruption of throttled body self learning for incorrect
environmental parameters (plausibility)

sh*t

So googled some more.. it could be a bad connection?
Im out to clean and inspect some more connectors to the throttle body.
Will post more....

the two codes just came from the compression testing because the throttle body was disconnected..

Cleaned throttle body in the same doing.. and made an relearn of the throttle.

codes still appearing:
P0301 & P0300

I think is on time to fix missing nuts for the bolts behind the exhaust manifold, maybe its sucking air in and misguiding the 02 sensor..

WHAT ELSE SHOULD I CHECK?

Check injector impedance. compare all 4 should be close.
What are the lambda 1 sensor readings like? make a graph with MES.

aurick86 - thanks for the suggestions. i measured the resistance on all 4 injectors to 16,1 ohm.

Ordered a new lambda/oxygen sensor for the (pre) catalysator.
The car has been driving 240.000 km, and i quess the lambda have to be changed anyways.

will see how it goes

I had the ECU out and cleaned the two connectors to it.. dirt almost poured out of them with electrical cleaner spray. The connector seems a bit burned on the "female" part, only spots at the connection holes...

Besides that, i found out that the MAP sensor propably was the source of all evil !

The MAP sensor connector was bad, and when moving the wires to the sensor, the car would almost stall. So i made a quick fix with strips and bending the inside of the connector for a stronger hold, and quess what.. the car didnt have any fails yet.

Im driving 60km on the highway later today, will see how it goes.

I hope this thread helps any one who still got this old close to extinct car.

So it started out fine, getting a better connection for the new MAP sensor i allready changed out helped..

Two years ago i changed the location of the cars ECU next to the battery which removed a lot of weird fault codes.

Yesterday i moved it back just to see if anything would change back.. and it did.. car went completely out of power 2-3 times when reaching highway speed.. starting everytime, just to go out.

Back home, change the position back, and no problems..
But the 3 cylinder problem is back every time starting the car and for 10 - 20 -30 seconds when driving..

the feel of 3 cylinders, could also be a (limp) mode, because the car is just out of power and a light vibration when the pedal is touched..

Are you still getting Cylinder 3 Injector Circuit Malfunction??

aurick86: Are you still getting Cylinder 3 Injector Circuit Malfunction??

P0203 - Cylinder 3 Injector Circuit Malfunction, No, that one only came up once, and never again.

P0301 & P0300, is still showing up.

The engine only gives me trouble at startup and sometimes at red lights when idling. Now the engine also a few times stopped, from 700 rpm to 0, for no reason at red light.

I ran some test with a graph (OBD car doctor) for iphone.

One thing i noticed was the throttle position, which once in a while flashed to NO SIGNAL on the app. See the graphs, all at idle, except intake pressure which i gave about 0-1500rpm and 2500rpm.

I also had the throttle body cleaned and also opened it to check the springs and electrics, all clear, but the electrics are not very visible.

Im still waiting for a new o2 sensor nr 1, and didnt fit the crankshaft sensor yet.

update.. no codes shows up anymore, i did a throttle relearn, but since i cleaned the d4 connector and electric connectors, i am now getting a (alternator failure.. and maybe something else), and the engine did cut out at red lights a few times.. no codes are stored. The engine starts every time again.

the text showing up when engine cuts out is:

asr failure - loose connection, text starting with alternator failure

Those fault codes are typical of an engine stall - so I wouldn't be reading too much into them. They are what happens we you get a sudden loss of power or significant drop - caused by the alternator stopping with engine stall.


If the throttle POT was on the way it should give you a fault code for this and you'd get some erratic running. I've known cars with dead throttle pots start up and idle beautifully but nothing happens in response to throttle peddle movement.


I'd be inclined to suggest crank sensor might be messing with you.


Have you done all the nice normal simple stuff like cleaning all your earths, battery terminal connections and that sort of thing?

Faults are gone so fare!
(I was getting P0300 and P0301, besides the "new" failures)


Started the car in the morning, with a short period of low power / 3 cylinder feel, the car woke up, and nothing came up the whole day, even went to a vehicle inspection which have to be done every 2.nd year, and the car passed / was coming up next month
So i hope i did something that might have fixed it.. but lets see.

I did:
- a second or maybe third clean of the D4 connection and the other beside it and also fastened them to the box with strip cables, so they wouldnt move when driving. Also jugged the cables a bit in... thats my sense of electric work, make them tight..

- Cleaned the earth that is visible when battery is taken out, under the battery box

- Cleaned wires to the ECU, and moved the ECU itself closer to the battery box.

- Took apart and cleaned the fuse box which i dont think was a problem, but just to be sure its clean inside.

- Had an extra ground wire set from battery minus to the ECU, and also grounded to the engine block, as it was originally.

- cable strip on earthwire to battery box, so they wouldnt move.

- cleaned the black thin wire which might be (b+) wire, at the alternator. When cleaning this with battery connected (only part which i did with battery on) be careful, i almost got shocked, my steel brush made some nice sparks when touching the exhaust cover, and the wire at the same time. Maybe same thing happening with the wire when driving, because it was bend down, and the plastic circle around was broken. I bended the wire-connector up so it wouldn't accidentally ground.

- Besides this i have been driving with injector cleaner in the fuel the last two tanks for about 2/3 weeks when the problems started..

Im still changing the lambda/oxygen sensor nr.1, and also going to change the crankcase sensor

Thanks for the suggestions, i will be back if the codes shows up again! :slayer:

P0301, P0300 & P0203 - Cylinder 3 Injector Circuit Malfunction, is back.. and the cars goes to limpmode /3 cylinders feel... now its also difficult to start, doesnt start in first go, and a security message is sometimes showing up, but disappearing again.

new codes arrived, p0202, and p0230 Fuel Pump Primary (Control) Circuit Malfunction

i fitted a new crankcase sensor, which is reached from under the car, no change.

When taking the voltage from the wires to the injectors, there are a steady voltage on all four wires, but when connected they give no voltage output?

I dont remember the exact voltage, but i think it was 2,3 volt when disconnected and ingition (key) on.

with the new codes.. im thinking it should be a bad wiring somewhere, or the ecu needs some attention.

Any suggestion ? please

Did you found the problem? I am currently getting p0638 along with random misfires on cylinder 3 and p0203 injector 3. Stilo 1.6 of course.