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Discussion Starter #1
Hello everyone,

I recently purchased a 2008 Alfa 159 3.2 JTS Q4 Automatic. As always, its one of the 3 159's in the entire country and only 3.2 in the country and the only automatic 159 in the country. I love the car to bits and according to the previous owner its been well looked after except for a mysterious ECU replacement!
I have used it for about 02 weeks and one fine evening the engine started struggling/mis-firing. When i parked smoke was pouring out of the engine compartment. When my mechanic removed the head...one coil pack has burnt, melted and fused itself to the head! WTF?
I have to order new plugs, new coil packs from UK.
Could anyone explain how this could have happened?
 

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I recall this was covered in a few threads on this forum, with various causes including faulty spark plug, relay ...
The scary part is that if the cause isn't corrected then bzzzt another coil pack gone. Was it #2 or #4?
 

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I too have this problem of nr. 4 coil melting (middle coil on front bank of 2007 model 159 Q4 3.2 JTS). There are a number of threads on this problem, it seems there are several owners with this exact same problem of number 4 coil melting. Mine has melted 3 in 5 months and 5,000 km. One member replaced coil, plug, injector, wiring harness from ECU and ECU without solving the problem. I have been monitoring the temperatures of the 3 coils on the front bank at random times with an infrared thermometer and they are always at the same temperature. The coil also has the amplifier/drivers integrated (has its own current supply) and gets the low voltage pulses directly from the ECU via wiring harness. It is the primary winding in the coil unit that heats up and starts melting the plastic which tells me that the pulse lenghts from the ECU may change under load conditions and overloads the primary winding, but of course I cannot say for sure. I just know that no one has been able to report back on a solution.

I believe there was an ECU firmware upgrade in 2011 but cannot find any information on what changed in this release. My next step will be to get Alfa dealer to check and confirm the version in the ECU on my car and then upgrade to the latest version if required. I will keep you posted.
 

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Hello everyone,

I recently purchased a 2008 Alfa 159 3.2 JTS Q4 Automatic. As always, its one of the 3 159's in the entire country and only 3.2 in the country and the only automatic 159 in the country. I love the car to bits and according to the previous owner its been well looked after except for a mysterious ECU replacement!
I have used it for about 02 weeks and one fine evening the engine started struggling/mis-firing. When i parked smoke was pouring out of the engine compartment. When my mechanic removed the head...one coil pack has burnt, melted and fused itself to the head! WTF?
I have to order new plugs, new coil packs from UK.
Could anyone explain how this could have happened?
Wrong spark plugs or spark plug gone open circuit? If the Impedance across the spark gap is greater than the impedance to the head, you will get arcing. This lower impedance includes the body of the coil pack which could suffer from "Tracking", just as a cracked distributer cap suffers. Plastic melts over the period until total failure but is the consequence of insulation break down. Making sure your spark plugs are the correct type.
 

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Discussion Starter #6
I recall this was covered in a few threads on this forum, with various causes including faulty spark plug, relay ...

The scary part is that if the cause isn't corrected then bzzzt another coil pack gone. Was it #2 or #4?


Hi, not sure. It’s the middle one on the top Bank of cylinders.


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Discussion Starter #7
I too have this problem of nr. 4 coil melting (middle coil on front bank of 2007 model 159 Q4 3.2 JTS). There are a number of threads on this problem, it seems there are several owners with this exact same problem of number 4 coil melting. Mine has melted 3 in 5 months and 5,000 km. One member replaced coil, plug, injector, wiring harness from ECU and ECU without solving the problem. I have been monitoring the temperatures of the 3 coils on the front bank at random times with an infrared thermometer and they are always at the same temperature. The coil also has the amplifier/drivers integrated (has its own current supply) and gets the low voltage pulses directly from the ECU via wiring harness. It is the primary winding in the coil unit that heats up and starts melting the plastic which tells me that the pulse lenghts from the ECU may change under load conditions and overloads the primary winding, but of course I cannot say for sure. I just know that no one has been able to report back on a solution.



I believe there was an ECU firmware upgrade in 2011 but cannot find any information on what changed in this release. My next step will be to get Alfa dealer to check and confirm the version in the ECU on my car and then upgrade to the latest version if required. I will keep you posted.


Pls do. It’s scary as it’s the only car of its kind here. Parts are non-existence. I’ll have to order everything from UK and shipping is super expensive.


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Discussion Starter #8
Wrong spark plugs or spark plug gone open circuit? If the Impedance across the spark gap is greater than the impedance to the head, you will get arcing. This lower impedance includes the body of the coil pack which could suffer from "Tracking", just as a cracked distributer cap suffers. Plastic melts over the period until total failure but is the consequence of insulation break down. Making sure your spark plugs are the correct type.


I’m replacing all the plugs to be in the safe side. Unfortunately parts will arrive only in end October. Have to wait to see


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Wrong spark plugs or spark plug gone open circuit? If the Impedance across the spark gap is greater than the impedance to the head, you will get arcing. This lower impedance includes the body of the coil pack which could suffer from "Tracking", just as a cracked distributer cap suffers. Plastic melts over the period until total failure but is the consequence of insulation break down. Making sure your spark plugs are the correct type.
I fully agree with your logic, that was the first thing I expected. I replaced all the spark plugs with the correct ones. After the second coil melt I swopped spark plugs on cylinders 4 and 6, The problem did not follow the plug as the melt occurred again on number 4 a month later.
If you do a search on this forum you will see that the occurrence is always number 4 for some unknown reason.
I contacted the Alfa Romeo dealers in Cape Town and although the service manager was very friendly and helpful in the sense that he took time to consult the other mechanics they cannot help me as they are not aware of the later version of ECU firmware neither do they have the correct equipment to flash it. They gave me a telephone number for AR South Africa technical assistance. When I called them they informed me that they do not accept calls from Joe public to their technical department, only from the dealerships. I explained that the dealership was not able to help me and that they gave me the number to phone. They reluctantly took my details and VIN number and promised to get their tech department to call me back. I'm not holding my breath.

By the way, the ignition coil is a Bosch unit. Alfa Romeo here is asking R4,775.00 for one (that is GBP265.00 at the current rate). I managed to get from a Bosch supplier for R790.00 (GBP44.00). How AR can charge 6 times more for the same product is robbery to say the least and yes, they confirmed that it was for a single unit and not all 6.
 

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Pls do. It’s scary as it’s the only car of its kind here. Parts are non-existence. I’ll have to order everything from UK and shipping is super expensive.


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It is a Bosch unit, you can source it from any Bosch parts outlet. Much cheaper than from Alfa Romeo.
 

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I’m replacing all the plugs to be in the safe side. Unfortunately parts will arrive only in end October. Have to wait to see


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What may not be understood is "Maximum Power Transfer occurs when the load is matched to the internal impedance of a generator". The voltage across the load is known as the P.D. - potential difference and this is half the EMF of the generator - because load and internal impedance of the generator are equal. So if a spark plug breaks down and goes open circuit, effectively, the coil pack now has double it's "Working Voltage" to cope with.

So it is important that spark plugs are checked. I don't understand why garages don't check the operating voltages for spark generation with a high voltage source. Remember, once the spark has been struck the impedance across the gap drops dramatically.

Making sure the coil pack is clean and grease free will also help, and it would also help to put some P.T.F.E. tape around it. Try to avoid scratching the surface as this can lead to "tracking". - just a suggestion!
 

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I used to own 159 with a different GM engine (1.8MPI, Z18XER), which is not the case here. But it used to burn coilpacks every 6 months or so, and each time on the same cylinder (#2).

I have discovered a lengthy discussion on Chevrolet Cruze forums about this issue (it has essentially the same engine), where after some time GM acknowledged the issue. The explanation was that the recommended spark plugs had incorrect gap between electrodes, which put additional load on coil pack, which consequently melted #2 each time. For that engine, recommendation was changed to Bosch FQR8LEU2, with a gap of 0.9mm. After the change of spark plugs, there were no more burnt coilpacks.

I'm not aware that there is a similar recommendation for 3.2JTS, but spark plugs are worth investigating. Sizewell has a point here.
 

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Discussion Starter #13
I used to own 159 with a different GM engine (1.8MPI, Z18XER), which is not the case here. But it used to burn coilpacks every 6 months or so, and each time on the same cylinder (#2).



I have discovered a lengthy discussion on Chevrolet Cruze forums about this issue (it has essentially the same engine), where after some time GM acknowledged the issue. The explanation was that the recommended spark plugs had incorrect gap between electrodes, which put additional load on coil pack, which consequently melted #2 each time. For that engine, recommendation was changed to Bosch FQR8LEU2, with a gap of 0.9mm. After the change of spark plugs, there were no more burnt coilpacks.



I'm not aware that there is a similar recommendation for 3.2JTS, but spark plugs are worth investigating. Sizewell has a point here.


I shall do that. Thanks. Awaiting for all the parts to arrive before running tests.


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Current owner of a 3.2 JTS. I was also burning coilpacks(twice) on #4 cylinder under very specific conditions which was pushing the engine hard for a period of around 30 minutes. At the time I was using Bosch HR7MPP302x -0.7 mm diameter centre electrode spark plugs and Bosch 0221604104(made in germany) coil packs. Bosch revised the coil packs which are now referenced as 0221604112 (made in slovenia) to address issues with the 104's. Don't know the full story.

Ultimately to resolve melting coils I dumped Bosch plugs and went for Denso 4719 Iridium ITV20TT (no need to gap them) - 0.4mm diameter centre electrode. They are specced for 1.1mm gap but ship slightly less. Apparently, one advantage of the smaller diameter center electrode makes life easier for iginition coils. End result..no coilpack problems over the last 5000 kms.

Another aspect is the resistance values associated with spark plugs, which i dont fully understand, but for interest sake those Denso's are 5000 ohm ..Bosch as mentioned above are 6000 Ohm. Equivalent NGK plugs are also 5000 ohm.
 
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Btw thevkanth .. that's #3 cylinder in your photos .. 1(timing side) 3 5 rear bank 2(timing side) 4 6 front bank
 

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Discussion Starter #16
Current owner of a 3.2 JTS. I was also burning coilpacks(twice) on #4 cylinder under very specific conditions which was pushing the engine hard for a period of around 30 minutes. At the time I was using Bosch HR7MPP302x -0.7 mm diameter centre electrode spark plugs and Bosch 0221604104(made in germany) coil packs. Bosch revised the coil packs which are now referenced as 0221604112 (made in slovenia) to address issues with the 104's. Don't know the full story.



Ultimately to resolve melting coils I dumped Bosch plugs and went for Denso 4719 Iridium ITV20TT (no need to gap them) - 0.4mm diameter centre electrode. They are specced for 1.1mm gap but ship slightly less. Apparently, one advantage of the smaller diameter center electrode makes life easier for iginition coils. End result..no coilpack problems over the last 5000 kms.



Another aspect is the resistance values associated with spark plugs, which i dont fully understand, but for interest sake those Denso's are 5000 ohm ..Bosch as mentioned above are 6000 Ohm. Equivalent NGK plugs are also 5000 ohm.


Oh crap. I already ordered the Bosch pugs!


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Current owner of a 3.2 JTS. I was also burning coilpacks(twice) on #4 cylinder under very specific conditions which was pushing the engine hard for a period of around 30 minutes. At the time I was using Bosch HR7MPP302x -0.7 mm diameter centre electrode spark plugs and Bosch 0221604104(made in germany) coil packs. Bosch revised the coil packs which are now referenced as 0221604112 (made in slovenia) to address issues with the 104's. Don't know the full story.

Ultimately to resolve melting coils I dumped Bosch plugs and went for Denso 4719 Iridium ITV20TT (no need to gap them) - 0.4mm diameter centre electrode. They are specced for 1.1mm gap but ship slightly less. Apparently, one advantage of the smaller diameter center electrode makes life easier for iginition coils. End result..no coilpack problems over the last 5000 kms.

Another aspect is the resistance values associated with spark plugs, which i dont fully understand, but for interest sake those Denso's are 5000 ohm ..Bosch as mentioned above are 6000 Ohm. Equivalent NGK plugs are also 5000 ohm.
Picked this little snippit up:- So... Your variables are:

1. Spark voltage - the higher the voltage, the longer the gap or higher cyl pressure may be.
2. Cyl pressure - higher pressure needs more voltage or a shorter gap.
3. Gap - Longer gap means higher voltage or less cyl pressure.
4. (turbulence)

I thought there may be some relevance as the specific circumstances were high load driving - vis a vis high cylinder pressure. There has been a lot of research into spark gap/cylinder pressure relationship. Certainly the centre electrode type of spark plugs are very effective in 105 series engines where the spark plug is central to the hemispherical head. I suppose the simple answer is to give the engine a break. Head temperature rises considerably under heavy load conditions and half an hour is a very long time. Don't know where in Britain you could do that.

Again a quote from another forum:-

What's the trade off? Fuel economy over ensured spark?

What if we were to gap all the plugs regardless of cylinder pressure
to 0.035"?

What is the harm? Would it cause premature wear to the electrodes?
Perhaps "bridging" if the gap is too tight?

I have used gaps between 0.040" and 0.055" with a MSD 6AL
and Blaster 2 coil, Accel 300+ wires and NKG UR5 plugs (one step colder)
on a first gen iron motor.

Cranking pressure is 235 PSI with an LOOSELY calculated static
compression of 11.2:1

All this on 92-94 pump gas with details in the signature link.

RE: Gap Setting Variance

I haven't noticed a performance gain, or fuel economy gain in over
7 years of driving this car and hundreds of passes down the 1/4 mile.

Am I missing out on something more?
The 0.035" referenced above is in the context of very high cylinder pressures from forced induction. Higher cylinder pressures require more voltage to jump the gap and if the ignition can't supply it you will have an inadequate spark. Most basic aftermarket ignitions can handle 0.035". Using a larger gap, if your ignition is up to it, sometimes makes more hp due to more rapid and complete combustion from the stronger/bigger spark. But 0.035" seems perfectly adequte with no real gains from a larger gap even if the ignition can fire it, at least for blower LT1 cars.

I have a pretty basic ignition (Opti, MSD6 box, MSD coil, stock wires) and have no spark related problems with plugs gapped to 0.035".

Rich Krause

Again, the relationship seems to be with high cylinder pressures, which would fit with a heavy right foot - essentially the engine is labouring under sustained load. Must investigate the old central electrode plugs again.
 

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Discussion Starter #18
Ok...so replaced the coil. Replaced all the plugs with Bosch. Did a complete tuneup including a injector clean.


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Discussion Starter #19
Ran it for a few miles and nothing has blown u yet but it’s a constant nightmare wondering when it’ll pop again.


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Ran it for a few miles and nothing has blown u yet but it’s a constant nightmare wondering when it’ll pop again.


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I'm interested in the final outcome. I have not resolved my problem yet. I have now gapped the NGK plugs the same as the Bosch at 1.1mm, the NGK plugs are gapped at 1.3mm from the factory.
Please update this post in the future, especially if your problem has been resolved.
 
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