Technical Misfire no3 cylinder

[The Panda Nut]

EML light flashed up and went out. Use of MES showns misfire on cyl 2 and 3. Actions, change plugs and oil, now completed well before due. No 3 plug centre electrode is very slightly cleaner than 12&4 so there is something very very slight going on here. I suspect the injector may actually be the cause or more likely the wiring harness as its showing signs of deterioration. The lable on this part seems to have a part number AG 0083888B does anyone know anything about obtaining this and fitting it. Following fitting new plugs.... still using the FPT made ones it does run notably smoother. New coil pack and leads fitted a few weeks back as well.

The car runs like a Rolls Royce so what all this warning message is about I have no idea.

I removed the throttle body and checked the manifold for gunge too and can report that it was sparkling clean and clear so the catch can is doing its job. I chuck out about 125cc of water and gunge every week!

 

[Popitinpete]

EML light flashed up and went out. Use of MES showns misfire on cyl 2 and 3. Actions, change plugs and oil, now completed well before due. No 3 plug centre electrode is very slightly cleaner than 12&4 so there is something very very slight going on here. I suspect the injector may actually be the cause or more likely the wiring harness as its showing signs of deterioration. The lable on this part seems to have a part number AG 0083888B does anyone know anything about obtaining this and fitting it. Following fitting new plugs.... still using the FPT made ones it does run notably smoother. New coil pack and leads fitted a few weeks back as well.

The car runs like a Rolls Royce so what all this warning message is about I have no idea.

I removed the throttle body and checked the manifold for gunge too and can report that it was sparkling clean and clear so the catch can is doing its job. I chuck out about 125cc of water and gunge every week!

Injectors very rare, what year and cc? If its 1.1 they have a problem with the injector loom where it splits in the 'Y' loom

 

[The Panda Nut]

Injectors very rare, what year and cc? If its 1.1 they have a problem with the injector loom where it splits in the 'Y' loom

Its a 2011 1.2 70HP 58716 miles Full and extremely comprehensive service history. Its been messing about for at least 25000 miles. Changing plugs seems to solve the issue for a while. All the plugs (8000 mioles use only) looked fine and it doesn't misfire. At about 80mph the EML comes on and puts the featr of god up me. 80 is actually 72 in the real world outside Fiats imagination! The light goes off by its self and when interrogated the fault is not presnet but stored in memory, presumably to bump up service costs!!! With new oil and plugs it is sounding majestic.

 

[koalar]

mark sure it got the right spark plugs. The eco should be the projected tip. They will run on standard plugs but not as Good. People often put cheaper plug in. This then gets copied

I doubt its a problem with the head gasket but a misfire on adjacent cylinders. Worth getting a compression test done just to eliminate this possibility otherwise you could chase your tail for weeks

 

[dagdromer]

can you do a test run with live data capturing in MES? this may help you identifying the source of your problem.
Are the fiat coils also waisted spark? I know at ford there are 2 coil drivers in the ECU, one for cilinder 1 and 4 and the other for 2 and 3. If there is an issue with spark and you already replaced the coil you may want to check the wiring to the coil and log the coildriver output.

 

[DaveMcT]

The plugs are fired in pairs 1-4 and 2-3. The ECU can detect which coil is giving unhealthy signals, but has no way to know which cylinder is misfiring. . Your symptoms sound like a weak ignition coil. For the costs, you might as well replace them both as the other coil wont be far behind.

 

[The Panda Nut]

can you do a test run with live data capturing in MES? this may help you identifying the source of your problem.
Are the fiat coils also waisted spark? I know at ford there are 2 coil drivers in the ECU, one for cilinder 1 and 4 and the other for 2 and 3. If there is an issue with spark and you already replaced the coil you may want to check the wiring to the coil and log the coildriver output.

Yes Im thinking this is the issue but will do compression and the replace the wires that feed 2 & 3 coils. Every normal car that I have ever run has had vastly worse plugs at change time. The ECU control causes a lot of issues for little benefit as far as I am concerned. This straight forward engine is being nannied to a silly extent.

 

[The Panda Nut]

The plugs are fired in pairs 1-4 and 2-3. The ECU can detect which coil is giving unhealthy signals, but has no way to know which cylinder is misfiring. . Your symptoms sound like a weak ignition coil. For the costs, you might as well replace them both as the other coil wont be far behind.

mark sure it got the right spark plugs. The eco should be the projected tip. They will run on standard plugs but not as Good. People often put cheaper plug in. This then gets copied

I doubt its a problem with the head gasket but a misfire on adjacent cylinders. Worth getting a compression test done just to eliminate this possibility otherwise you could chase your tail for weeks

I dont think its head gasket, but will check as suggested as it could be early signs.

The plugs are fired in pairs 1-4 and 2-3. The ECU can detect which coil is giving unhealthy signals, but has no way to know which cylinder is misfiring. . Your symptoms sound like a weak ignition coil. For the costs, you might as well replace them both as the other coil wont be far behind.

I am thinking wiring. Its unclear if misfire means spark or emissions but I guess spark. If its misfiring at all you could fool me! This car as one coil pack only.

 

[MrMagoo]

Are you able to swap leads 2 and 3 at the coil pack?

 

[koalar]

Are you able to swap leads 2 and 3 at the coil pack?

not easy with the eco as it block not two separate coils

I can't recommend doing this

But what I Normally just flip a HT lead off the coil pack one at a time and start the car. With a screwdriver connected to earth and see how large the spark jumps. If all 4 are about the same the coils are normally fine

First if you have a pacemaker its very dangerous. Dont even think about it
Second if you do it wrong you could get a nasty belt. The spark needs an easier path to earth than you hand.

for safety so it can't go across my heart I put my other arm behind my back and dont lean on the car

third your suppose to but I dont bother, disconnect the injector to stop the fuel wiping the oil off

takes about 2 minutes to check all 4 like this.

i will leave it up to you if you want to try. As a bonus if one cylinder isnt firing well you will hear no difference when that HT lead is removed

 

[dagdromer]

Looking at the plug on the coilpack I see a 6 pin connection. I assume that it is 1 ground, 1 12v and 4 coil inputs. So it seems that this is not waisted spark and each cilinder has its own coil driver in the ECU.
Then the test that @koalar suggested should give you a proper indication. As you don't want to flush the cilinders with petrol you can also take out the fuelpump fuse.

best way to make sure that all coildrivers are working fine is finding a obd software tool that can scope the signals or even better measure directly on the coilpack wires and put the 4 signals on a scope. then you will find any odd behavior and take actions on that.