Technical Fiat Stilo 1.6 Hesitation

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Technical Fiat Stilo 1.6 Hesitation

thatengineer

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Hello all, from a new boy.

I'm struggling with my Stilo MW, and need your help!

My Fiat Stilo, 1.6 2006 Plate is misfiring under load, with fluctuating idle. As you put load on, it will "yuk and snatch" to a point, but sometimes come out of the other side of it.

The error code it comes up with 95% of the time is P0203, Cylinder Injector Malfunction - Cylinder 3. Sometimes it will treat me to P0201 too.

The story so far:

Throttle body taken off and cleaned up (was quite dirty)
Injector sent for servicing and refitted (Test reports good)
Fuel rail checked for cleanliness (Clean)
Injection loom to the injector checked for resistance and intermittent wire breaks (OK at all around 15 ohms)
Ran with MAP sensor disconnected (Still same fault)
Coils swapped around to check (No change)
Spark plugs checked (Gaps okay, a little white, but not too bad)

The fiat has a MAP sensor rather than a MAF sensor, so any splits or loose clips in the intake trunking upto the throttle body would have no affect, as it is manifold pressure that is monitored rather than mass.

The MAP sensor was removed and cleaned already, but the conditions seem to be getting worse rather than better with the idle getting worse rather than better, now progressing to cutting out within the erratic idle. I did note (via the diagnostics I do have) that under acceleration when it is snatching, the advance drops back to 5-10% , before picking up to a more healthy 30-50%.

Any thoughts?

Many thanks.
 
The error code it comes up with 95% of the time is P0203, Cylinder Injector Malfunction - Cylinder 3. Sometimes it will treat me to P0201 too.

Injection loom to the injector checked for resistance and intermittent wire breaks (OK at all around 15 ohms)

Hi, Welcome to the FF.

The wiring between each injector and the engine management ECU should be 0Ω ..... not 15.
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Many thanks for the reply.

I should have said that that is the resistance of the loom via the injectors. I tested the loom itself whilst it was off with zero resistance, even with a lot of wiggling around.
 
P0203 refers to number 3 injector circuit malfunction. If the wiring is OK, then it could be a fault with the actual injector.

Swap number 3 injector with another one (not number 1 if that's sometimes showing a fault), then run the car and check for fault codes again. If the code changes to where you've put number 3 injector, then the injector is faulty.
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Tried that this eveing to no avail, and the injectors were serviced as my first thought.

It's a tricky one!

Knock sensor or crank angle sensor?
 
Any thanks Darven - is there anyway of testing this?

No way of testing the ECU other than sending it to one of the remanufacturers.

Forum member Dracco121 posted a video of how to repair a common problem with the 1.6 EM ECU here: https://www.fiatforum.com/stilo/342336-computer-easy-fix.html

The problem with the connector pins can cause many different engine faults.

There's also a know problem with the ECU overheating because of its location on the engine. Several members have moved the ECU to a cooler location.
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Having removed the ECU, and whipped the back off, not a single dry joint or sunken pin on the board.

What on earth else may cause these symptoms?
 

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i am currently having the same exact symptoms. was noticing my throttle jerking around especially in the 1,000-3,000 rpm range and my engine fault light coming up. That first time that happened i checked the codes and was
p0201
p0203
p1121
p1120. My spark plugs are changed every 15,000 klm.

i took it to the garage and did an ultrasound cleaning which helped only the first couple days then again the same problem i feel like im gonna damage the engine with that jerking at those rpms. i dont think it should be an ecu problem because i changed it 2 years ago.

Did you find a solution to your problem?
 
just measured resistance on the injector plug and got around 18 ohms on all four. Is it normal to see this much cause i say on the forum it is around 14 normally. Also cleaned the plug which seemed a bit dirty will test soon.
 
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