Burnt ignition coil Topic is solved

vbertone · Post by **vbertone** » 17 Jul 2019, 11:22

Hello all, well not sure on this one but it's a head scratcher. Maybe some of you have seen this but i have not. 2009 s8 T6 3.0, melted ignition coil, no warning what so ever. Now car won't start and it sounds like no compression in the engine? It is my daughters car, and its at the shop but I worried of the outcome at this point. Only 126K miles...any thoughts? Changed battery on a Thursday, no issues, then Saturday daughter says car was acting weird, ck engine light, shaking, and she pulled over. I got to her 5 minutes later and you could smell the electrical burning smell. I literally watched the ignition coil burn up. Thanks ahead of time...

Post by **pgill** » 17 Jul 2019, 12:26

There is some evidence that a broken Thermostat causes the engine to run hot and the ignition coils to fail

http://www.volvoxc.com/forums/showthrea ... -2009-XC70

If you want to know why the Thermostat fails then take a look at this link (scroll down and look for the pictures)

viewtopic.php?f=31&t=86205

As for the problem that you are experiencing right now it is likely that the Fuse is broken.

Replace the Coil and the Fuse and your Volvo will likely start.

But as I stated above the Thermostat has likely failed

Take Care

Paul

vbertone · Post by **vbertone** » 17 Jul 2019, 14:27

Thank you Paul. Which fuse would it be?

vbertone · Post by **vbertone** » 17 Jul 2019, 14:34

Also forgot, why would it seem like no compression after all that? The shop is checking it out but I like to know these things as they go wrong. Thanks

Post by **pgill** » 17 Jul 2019, 14:56

I believe that it should be fuse 35

I am not sure if this fuse is located on the lower level of the fuse box because I've never replaced mine

: Untitled.jpg (172.46 KiB) Viewed 4792 times

As for your other question about what the engine sounds like when it doesn't start.

It has been my experience that the engine sounds very different when it is just cranking vs. when it starts

Let us know what you find out

Good Luck

Paul

Post by **jimmy57** » 17 Jul 2019, 15:29

my 2010 XC60 T6 went down this road a couple of weeks back. I wasn't driving it but electrical system service needed meg, misfire, stepped into to make it go, lost even more power, then quit running and coasted to side of road and would not do anything, not even hazard flashers. I collected spouse and wrecker towed it to the house. I attached battery charger and its breaker clicked off repeatedly. I traced the current draw to the alternator and stopped the charger cycling by disconnecting the B+ cable. I changed alternator, #5 coil, nd the fuse for coils. It started, ran smooth but had low power when I drove it. I checked bypass valve and wastegate and then removed catalytic converter and found the melted front stone. I have seen COP coils fail when charging system quits on Volvo and other makes. The coil ramps up current when voltage goes down to keep spark voltage at desired level. The usual purpose for this is during starting when starter lowers voltage available. Catalyst is no fun on these. The least troublesome way to remove it is to pull RH axle then angle gear and then you can get to the forward bolts. The front forward hole on CC is slotted so that bolt does not have to be completely removed. Angle gear oil is really easy to change when it is out............

Post by **pgill** » 17 Jul 2019, 16:01

jimmy57 wrote: ↑17 Jul 2019, 15:29 Angle gear oil is really easy to change when it is out............

Just remove one of the bolts a drill a drain hole

see this link for more information

https://www.freel2.com/forum/topic14659-15.html

Thanks

Paul

Post by **pgill** » 17 Jul 2019, 16:07

Jimmy,

Thanks again for another excellent explanation

Now this make more sense

The 3.2L Si6 engine ignition system has a single iridium tipped spark plug per cylinder, with each spark plug powered by an
on-plug ignition coil. The ignition coils are directly driven by the ECM.

Power for the ignition coils is supplied from the main relay and a fuse in the BJB. A capacitor is connected in parallel with
the power supplies to the ignition coils to suppress RFI (radio frequency interference).

Each ignition coil contains a power stage to switch the current in the primary circuit. The ECM controls the switching with a
signal to the power stage. The ECM monitors operation of the ignition coils using a feedback signal from each of the power
stages. If a fault is detected the ECM stores an appropriate fault code.

The ECM varies the dwell time of the ignition coils depending on battery voltage and engine speed, to ensure a constant
energy level is produced in the secondary coil each time the power stage is switched. This ensures a good spark is always
produced by the spark plug without excessive primary current flow, thus avoiding overheating or damage to the ignition coils.

Take care

Paul

Post by **jimmy57** » 17 Jul 2019, 20:20

"Just remove one of the bolts a drill a drain hole"

I have the drain, It got that within 24 hours of me buying it and then fussing with the things I always fuss with.

But it still runs out faster through the fill plug with unit upside down after you've removed AG because the %&#%()#))@)@)) cat can bolts on turbo were the foundation on which the car was built.

I'm thinking some Volvo engineers had beloved wives that ran off with Volvo techs and they got payback with the blower motor and CC bolts on P3s.

Post by **pgill** » 18 Jul 2019, 11:14

Jimmy,

The problem that you are encountering is due to advancements in mechanical CAD.

The problem with CAD is that is you zoom in enough it always looks like there is enough room.
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Having said that your theory about Infidelity may also have some merit

I'll have to think about it.

I am on the original Cat for both my cars

2008 LR2 (~120K)
2010 S80 (~130K)

The S80 has a PZEV warranty for the Cat until 2025 or 150K

So if that one fails I won't be changing it out

Thanks

Paul