[t6.mohamed]

Well, my T6 had a moment today. Engine-wise. the car has been rock-solid for me. Never even had any issues with oil consumption. I’m at 125k miles now, and today the car started misfiring after I got fuel. The check engine light was flashing, along with a message on the screen saying “shift up or slow down”, with a coolant symbol. Alarmed. I shut the car off, and restart it, same issues. I then open the hood, and there’s white smoking coming from what appears to be the ignition coils, along with a plasticy smell. I immediately shut the car off, and a few minutes later, I try to start the car. It cranks but it doesn’t turn over. I plug in a code reader, and cylinders 3, 5, and 6 are all misfiring. I’ll find out the exact codes later on. I just want to know how major of a repair I’m in for. Either way, my car is out of commission.

 

[Wayne T5]

Sounds like coils and plugs are in your future.

 

[t6.mohamed]

Ordered new coil packs, and after a little bit more digging I found more people having the same issue, and get this around the same mileage. They also had to change their ignition coils and then they were good. I blame myself for this situation because I wasn’t aware that the coil packs should’ve been replaced by 100k miles. Now I just have to wait for them to come through, and attempt to change them on my own, which luckily appears to be an easy job.

Side note: the worst part of your car breaking down is nobody wants to help you out, or am I just surrounded by the wrong people? Probably the latter.

 

[Wayne T5]

Cars are a mystery to most folks so wouldn't really have much to offer aside from a ride somewhere.

 

[t6.mohamed]

well, I replaced all six coils and Cece is back to running smoothly, with a couple asterisks, of course. The check engine light is still on, only it’s not blinking this time. Not too big of a deal. But what might be a big deal is the screws that were holding all the ignition coils in place were so garbage that every single one of them broke in two as I was unscrewing them.
Other than that, moral of the story is change your coils by 100k miles so you don’t have a situation like me.

 

[paradoxicallymodified]

Well, my T6 had a moment today. Engine-wise. the car has been rock-solid for me. Never even had any issues with oil consumption. I’m at 125k miles now, and today the car started misfiring after I got fuel. The check engine light was flashing, along with a message on the screen saying “shift up or slow down”, with a coolant symbol. Alarmed. I shut the car off, and restart it, same issues. I then open the hood, and there’s white smoking coming from what appears to be the ignition coils, along with a plasticy smell. I immediately shut the car off, and a few minutes later, I try to start the car. It cranks but it doesn’t turn over. I plug in a code reader, and cylinders 3, 5, and 6 are all misfiring. I’ll find out the exact codes later on. I just want to know how major of a repair I’m in for. Either way, my car is out of commission.

What? You didn't order toast with your fill up?

 

[paradoxicallymodified]

well, I replaced all six coils and Cece is back to running smoothly, with a couple asterisks, of course. The check engine light is still on, only it’s not blinking this time. Not too big of a deal. But what might be a big deal is the screws that were holding all the ignition coils in place were so garbage that every single one of them broke in two as I was unscrewing them.
Other than that, moral of the story is change your coils by 100k miles so you don’t have a situation like me.

when you changed them was the was the engine warm or cold?

 

[JMcAz7]

If you had multiple coils fail at once, I would think to check the grounding of the coils. In general, most coil packs share a common ground to the valve cover, at least from my observations back when I was a Hyundai/Kia mechanic.

Just a thought. I have no doubt they fail over time, but if you had multiple fail at the same time, there's probably something common that drove the failure.

 

[t6.mohamed]

when you changed them was the was the engine warm or cold?

It was cold. It didn’t run for 4 days

 

[t6.mohamed]

If you had multiple coils fail at once, I would think to check the grounding of the coils. In general, most coil packs share a common ground to the valve cover, at least from my observations back when I was a Hyundai/Kia mechanic.

Just a thought. I have no doubt they fail over time, but if you had multiple fail at the same time, there's probably something common that drove the failure.

It was only one that failed. I replaced all of them tho

 

[t6.mohamed]

Well, as an update, I managed to fix the screw situation and put brand new screws in place. The car is fine with normal driving, but it still misfires a bit under hard acceleration especially past 3,200 RPM, and misfires hard if you stay in it, complete with the engine light flashing. I took it to a mechanic, and they suspect the fuel is the issue. Went ahead and put seafoam, fuel injector clean, and octane booster. It could be a placebo effect, but the car already feels happier, although I haven’t pushed it hard yet. I’m going to wait a few days before doing so. I’ll stay in touch.

 

[t6.mohamed]

Update:
Even after the fuel treatment, I noticed the car still misfired at higher RPMs, except it wasn’t just at higher RPM. I realized that under any occurrence of boost, it would misfire slightly, depending on percentage of throttle.

So, full disclosure, after the initial breakdown, I bought the ignition coils on ebay by a third party manufacturer, non-OEM. I understand that many people have reservations for non-OEM parts, but I bought them because I have never had an issue with third party parts, and I also can’t afford OEM. After the fuel treatment didn’t seem to fix the problem, I started to blame the eBay brand ignition coils. My hypothesis was they could not provide the spark needed to properly ignite the fuel when boost is applied. Maybe they were designed and tested for the 3.2 I6 cars and not the 3.0T. Since I can’t afford new OEM, I bought the next best thing: used OEM.

After I installed the used, but OEM ignition coils, I went for a test drive. I did some semi-aggressive driving, and the car seemed to boost properly this time. The driving experience resembled how the car was prior to the whole ignition coil mess. 3 minutes later, heavy misfire, once again. This time, it did not stop. The car was running so bad in fact, I thought I did some permanent damage to the engine. I once spun a rod bearing on the 07 Prius I used to drive, and my S60 sounded and felt just like that. I go back home, re-installed the eBay brand ignition coils, the engine is running smoothly once again. I can breathe now.

Then, it hit me. The airbox lid was so loose, that the air filter was exposed. All the screws that were supposed to hold it in place were threaded. I go to the store, zip-tie the airbox lid shut where the screws would’ve been; now it is secure. Also, I installed a new air filter I’ve been meaning to put on. I go for a drive, and guess what? The intermittent jitters under boost is now gone. To be honest, I have yet to go WOT because I’m too afraid of something going wrong. That said, quarter throttle, half throttle applications where the car would’ve previously hesitated, or misfired if you would’ve stayed in it, the car is now boosting properly. All the same, it is a bit hard to tell since my tires are worn and unbalanced; I need to get new ones before I can make a definitive statement.

I’m still suspicious of the eBay brand ignition coils. I’m not fully trusting of them just yet, but my car is at least more than good enough to get by. I plan on buying OE coils down the line, but until then I believe I solved the issue with my car. What do you think?

 

[CYB3RBYTE]

Having the same issue with our XC60 T6 with new BREMI coils from FCP and OEM Volvo plugs, done about 8 months back. One of the snaps for our airbag is gone as well, wondering how that could correlate... it shouldn't cause a different for misfires as the car should be putting out codes for intake / mass air flow issues.

 

[t6.mohamed]

Having the same issue with our XC60 T6 with new BREMI coils from FCP and OEM Volvo plugs, done about 8 months back. One of the snaps for our airbag is gone as well, wondering how that could correlate... it shouldn't cause a different for misfires as the car should be putting out codes for intake / mass air flow issues.

Is the airbox lid exposing the air filter? Could it easily move? If so, then I have a hunch that that can cause misfire under boost. Either that, or some other type of vacuum leak. Note that I’m no mechanical expert. This is just a simple guess from me.

Now, if the misfire is constant, then it’s definitely the plugs or coils that are at fault. If it is intermittent, like in my case where it only seemed to occur under boost, it could be something else, like bad fuel or insufficient air.

Also, it could be that these ignition coils need to be broken in after install.

Idk I just need an expert to confirm if these are true or if I’m just talking out my ass lol

 

[t6.mohamed]

Since my tires are unbalanced, it’s a bit hard to tell if I fixed the issue or not, so, sitting stationary, I revved to 3,500 RPM for about 15 seconds, no issue. Then I did it again but this time at 4,000 RPM for 25 seconds, without a hitch. I think I solved the problem.

 

[budleach]

If you had multiple coils fail at once, I would think to check the grounding of the coils. In general, most coil packs share a common ground to the valve cover, at least from my observations back when I was a Hyundai/Kia mechanic.

Just a thought. I have no doubt they fail over time, but if you had multiple fail at the same time, there's probably something common that drove the failure.

I still suspect this might be your issue. Even though only one coil pack failed, you did claim to have error codes for misfires on multiple cylinders. This makes me think either a common ground issue, or just bad fuel. I assume you have burned through that tank of fuel and refilled by now though? All this talk of coils, did you replace plugs as well?

 

[budleach]

Since my tires are unbalanced, it’s a bit hard to tell if I fixed the issue or not, so, sitting stationary, I revved to 3,500 RPM for about 15 seconds, no issue. Then I did it again but this time at 4,000 RPM for 25 seconds, without a hitch. I think I solved the problem.

Misfires and/or detonation are always most likely to occur under load (high boost). So stationary revving is unlikely to re-create the symptoms.

 

[t6.mohamed]

I still suspect this might be your issue. Even though only one coil pack failed, you did claim to have error codes for misfires on multiple cylinders. This makes me think either a common ground issue, or just bad fuel. I assume you have burned through that tank of fuel and refilled by now though? All this talk of coils, did you replace plugs as well?

Plugs were changed 30k miles ago

 

[t6.mohamed]

I still suspect this might be your issue. Even though only one coil pack failed, you did claim to have error codes for misfires on multiple cylinders. This makes me think either a common ground issue, or just bad fuel. I assume you have burned through that tank of fuel and refilled by now though? All this talk of coils, did you replace plugs as well?

To go about fixing that, will I need new connectors?

 

[budleach]

I haven't looked at my T6 in a while so I do not recall the exact number and location of ground points. In most modern coil on plug engines there is typically a ground wire (for ECM) integrated with the part of the wire harness that has all the coil pack plugs that will bolt directly to the valve cover somewhere. There is also usually a larger wire or open braided metal strap that will connect the cylinder head to the chassis somewhere. Visually inspect for any wires or braided cables (ground straps) that are bolted directly to a bare metal point on the cylinder head / valve cover. Ensure they are all clean with good tight electrical contact. Check for breaks, loose connections, corrosion, discoloration of bare braided metal straps, evidence of mice activity, etc. Use a multimeter, if you have one, to check continuity.

The spark plugs only work because the body of plug is electrically grounded through metal to metal contact between the threaded interface with the cylinder head. If the cylinder head is not adequately grounded to the chassis (and chassis to negative battery terminal), it can lead to all sorts of electrical issues.

Let's not overlook the obvious here. In your first post you claim your symptoms suddenly started after you got fuel. The simplest explanation is usually the right one. Dumping in a bunch of fuel treatments isn't a cure all for bad gas. You still haven't indicated whether the gas that was put in the tank immediately before the symptoms manifested has been completely burned up and replaced with new gas. How much did you put in the tank? How much was already in the tank? Have you added any since? Rule that one out first before reloading the parts cannon.