Technical engine misfiring, stalling with multiple issues

[4ceps]

Hey team

Was hoping to get some technical help as I'm at my wits end fixing the missus' 500x 1.4L mutliair turbo from 2017.
RHD. FWD 103kw model.
The dealership are fully booked out for another month (!) and my mechanic is on leave so I thought to try do some of it myself (coming from someone who used to self-service all Japanese cars).

Recently has had problems with stalling, rough idling and misfiring. Started off with cylinder 3.

Running a mobile phone code scanner:
OBD-II DTCs: 4
P130A [0x130A] Status: Confirmed
P0106 [0x0106] Manifold absolute pressure (MAP) sensor/barometric pressure (BARO) sensor - range/performance problem Status: Confirmed
P0303 [0x0303] Cylinder 3 - misfire detected Status: Pending
P0300 [0x0300] Random/multiple cylinder(s) - misfire detected Status: Pending
============================
Engine control unit DTCs: 6
P0303(00) [0x030300] Cylinder 3 - misfire detected Status: Pending, Confirmed, Test not completed during this operation cycle
P0300(00) [0x030000] Random/multiple cylinder(s) - misfire detected Status: Test failed, Pending, Confirmed, Test not completed during this operation cycle
P130A(00) [0x130A00] Status: Confirmed, Test not completed during this operation cycle, Warning indicator requested
P0106(00) [0x010600] Archive (inactive) Manifold absolute pressure (MAP) sensor/barometric pressure (BARO) sensor - range/performance problem Status: Confirmed
P0301(00) [0x030100] Archive (inactive) Cylinder 1 - misfire detected Status: Confirmed, Test not completed during this operation cycle
P0302(00) [0x030200] Archive (inactive) Cylinder 2 - misfire detected Status: Confirmed, Test not completed during this operation cycle
============================
Transmission control unit No DTC found.
============================
BCM DTCs: 2
U1736(87) [073687] Archive (inactive) Status: Confirmed
B106D(86) [0x906D86] Status: Pending, Confirmed
============================
ACC No DTC found.
============================
ESM (Electronic shifter module) No DTC found.
============================
IC No DTC found.
============================
RFH No DTC found.
============================
RFH No DTC found.

I've changed all the spark plugs to NGK sparkplugs, swapped the coils around. Even pulled out each ignition coil serially to see if it would make a change in the firing and it went really rough individually so I don't think it's any of the coils gone bad. I've reset the error codes to see if it'll spit out another error after changing the spark plugs but nothing popping up now despite the car stalling and being just as bad!

For what it's worth, the cylinder 3 spark plug was quite disgusting and had a lot of soot near on it.

When I rev it to 4000rpm and let it drop back down to idle, then this really exaggerates the problem. Currently it's really rough idling and half the time it'll stall when I'm idling. And it's a struggle to restart it, on occasion it'll not turn over, just splutter for a bit before stalling. It'll take 2-3 attempts to turn it off.

I'm at my wits end what to do and I don't really want to fire the parts cannon anymore unless someone has some idea?

Thank you in advance.

 

[s130]

Sorry for the order, but here are some of the error codes which I've corrected/expanded on

334 - 500X 1.4 Turbo MultiAir Drivestyle System - Signal invalid B106D-86

334 - 500X 1.4 Turbo MultiAir Entertainment Telematic Module (ETM / LTM) - Missing message U1736-87

334 - 500X 1.4 Turbo MultiAir Misfire 200 (Component or system over temperature) P130A-00

334 - 500X 1.4 Turbo MultiAir Intake manifold pressure sensor (Signal rate of change above threshold) P0106-00

334 - 500X 1.4 Turbo MultiAir Misfire random (performance or incorrect operation or component or system over temperature, misfire
1000 or misfire 200) P0300-00

334 - 500X 1.4 Turbo MultiAir Misfire cylinder N (performance or incorrect operation component or system over temperature, misfire
1000) P030N-00

The P0300-00 code appears to be a catch all associated with the P030N-00 codes.

Things to check list are very long. Wiring, connectors, fuel pressure/pump, fuel quality, leakage in inlet & exhaust manifolds, compression check, injector check, .......

 

[Ralf S.]

Curious one. The fact that it "knows" it's misfiring suggests it's an ignition problem rather than a fuel problem... so for the moment forget about fuel pump, regulator or throttle body issues... if an injector was blocked, for example, the car would still be going through the motions, albeit trying to ignite fresh air.

It could be a good, old-fashioned TDC sensor problem.. if the sensor is failing that will send the ignition/injection functions all over the place. You can't easily test a TDC sensor, so if it was me.. I'd stick a new one on there to eliminate that as a potential issue.

I had similar symptoms once on my old (fairly analogue) Alfa 145 when the throttle body was all gummed up... so it may be worth cleaning the b'jesus out of the valve. There will be something that converts the throttle position into an electrical signal.. usually a rotating cylinder or valve.. so that's the place to clean up.

Cylinder 3 sounds concerning. Oily soot is not good... the injector could be dumping in way too much fuel for the cylinder to burn (although the other cylinders would carry one flooded cylinder) or there is oil in there... either from a head gasket leak or a FUBAR valve stem seal. You might need to do a compression check (wet and dry) to determine whether it's good, or if not, whether it's valves or gasket... but even if Cyl. 3 had a holed piston, it wouldn't cause all those ECU errors by itself.. so it could be something to look at later.


Ralf S.

 

[4ceps]

Hey team

Thanks for your advice so far. If anything the car is struggling even more now. Not able to start up will need two or 3 attempts at pressing the button every time and driving at low speed <15km/h causes the car to splutter and misfire like crazy.

Any thoughts?

Updated car scanner below

Car Scanner ELM OBD2
Version: 1.105.0/1.105.0/iOS
DTC report
Connection profile: Fiat Fiat: Ducato; Peugeot: Boxer/Manager; Citroen: Relay/Jumper; RAM: ProMaster; Opel/Vauxhall: Movano 2.2 HDIDate: 3/21/2024 4:28:57 PM
VIN:
============================
OBD-IIOBD-II
DTCs: 4
----------------------------
P130A [0x130A]
Status: Confirmed
----------------------------
P0106 [0x0106]
Manifold absolute pressure (MAP) sensor/barometric pressure (BARO) sensor - range/performance problem
Status: Confirmed
----------------------------
P023E [0x023E]
Manifold absolute pressure (MAP) sensor/turbocharger (TC)/supercharger (SC) boost pressure sensor B - correlation
Status: Confirmed
----------------------------
P0105 [0x0105]
Manifold absolute pressure (MAP) sensor/barometric pressure (BARO) sensor - circuit malfunction
Status: Confirmed
============================
Engine control unitEngine control unit
DTCs: 7
----------------------------
P1524(00) [0x152400] Archive (inactive)
Variable Intake Solenoid System
Status: Confirmed
----------------------------
P0301(00) [0x030100] Archive (inactive)
Cylinder 1 - misfire detected
Status: Confirmed
----------------------------
P0300(00) [0x030000] Archive (inactive)
Random/multiple cylinder(s) - misfire detected
Status: Confirmed
----------------------------
P130A(00) [0x130A00] Archive (inactive)
Status: Confirmed
----------------------------
P0106(00) [0x010600] Archive (inactive)
Manifold absolute pressure (MAP) sensor/barometric pressure (BARO) sensor - range/performance problem
Status: Confirmed
----------------------------
P023E(00) [0x023E00]
Manifold absolute pressure (MAP) sensor/turbocharger (TC)/supercharger (SC) boost pressure sensor B - correlation
Status: Confirmed, Warning indicator requested
----------------------------
P0105(00) [0x010500]
Manifold absolute pressure (MAP) sensor/barometric pressure (BARO) sensor - circuit malfunction
Status: Pending, Confirmed, Warning indicator requested
============================
Transmission control unit
No DTC found.
============================
BCMBCM
DTCs: 2
----------------------------
B162E(15) [0x962E15] Archive (inactive)
Status: Confirmed
----------------------------
B106D(86) [0x906D86]
Status: Test failed, Test failed (current drive cycle), Pending, Confirmed
============================
ACC
No DTC found.
============================
ESM (Electronic shifter module)
No DTC found.
============================
IC
No DTC found.
============================
RFH
No DTC found.
============================
RFH
No DTC found.

 

[Ralf S.]

Hey team

Thanks for your advice so far. If anything the car is struggling even more now. Not able to start up will need two or 3 attempts at pressing the button every time and driving at low speed <15km/h causes the car to splutter and misfire like crazy.

Any thoughts?

Updated car scanner below

I had another thought..

Your beast is a Multiair.. and the similar tech in the 500 Twin-Air does give misfire problems when the variable valve operation starts going AWOL.

The TA/MA systems rely on solenoids to fill oil chambers that affect the effective valve length, and therefore the valve timing. They seem to be quite sensitive to having plenty of clean, correct-grade oil, otherwise the system doesn't operate smoothly (or develops faults) and that throws out the valve timing, which obviously would affect what's in the cylinder when the car is trying to ignite it.

The TA system also has an oil strainer that is supposed to be maintenance free but it gets clogged and that is part of (though not the exclusive cause) of the "develops faults".

Anyhow.. regardless of the cause, your problem could be a mis-functioning MA system. There must be a way for a Fiat dealer to plug it in and replicate the correct operation (or otherwise)... so since none of your issues seem to have a conventional cause, I would look at getting the MA checked out.


Ralf S.

 

[4ceps]

The TA system also has an oil strainer that is supposed to be maintenance free but it gets clogged and that is part of (though not the exclusive cause) of the "develops faults".

Hey Ralf

Interestingly I did come across this so I had taken the strainer out and cleaned it (couldn't get a spare delivered the same day). It looked fine, minimal amounts of solid junk stuck in the sieve, small shards of what looked like metal.

Error still the exact same.

Interestingly I was driving it today to see if the problem would recur and I took a roundabout a little fast and it stated "engine oil pressure problem" whilst I was in the roundabout. As I pulled out of the roundabout the error had already disappeared, but I wonder about the engine oil.

Yeah, I've booked it for the first available appointment at the dealership which is still mid next month which is really frustrating - and hence I was hoping if anyone here knew what was going on.

Thank you though.

 

[s130]

Have you checked the engine oil level?

There is no oil "level" warning system on the 500X to my knowledge. Only oil pressure as far as I'm aware.

Going round a roundabout at speed will cause the oil to drain away from the oil pump pickup and if the oil is low then the pressure will drop and fire a oil pressure warning. Stop the G force and the problem will go away.

On my 500X to check the oil level with no smudges I of course clean the level stick but then do "dip tests". i.e. Insert stick to bottom of plastic top ring. Then to "O" ring and then fully in. You will be able to see the stick progressively get wetter.