Porsche 996 misfire after rain

[sky217]

I have 2003 996 with 84k miles that hates the rain. Was wondering if anyone had a similar issue and figured out a solution. I get engine check lights on and flashing with the car shaking after each time it rains. Checked the code and I am getting random misfires and cylinder 5 and 1 misfire.

 

 

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[JFP in PA]

26 minutes ago, sky217 said:

 

I have 2003 996 with 84k miles that hates the rain. Was wondering if anyone had a similar issue and figured out a solution. I get engine check lights on and flashing with the car shaking after each time it rains. Checked the code and I am getting random misfires and cylinder 5 and 1 misfire.

 

 

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Check your coil packs, one or more is cracked.

[sky217]

 
Check your coil packs, one or more is cracked.

I just checked those not long ago and they were fine. I just changed the spark plugs too


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[judgejon]

Yep, change out all coil packs. 

[judgejon]

1 minute ago, sky217 said:

I just checked those not long ago and they were fine. I just changed the spark plugs too


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Still possible small cracks are doing you in.  What happens after you wash car, or hose it off?  Is car outside in rain, or garaged?  What you described sure seems like classic coil pac issue.  Good luck.  

[sky217]

Still possible small cracks are doing you in.  What happens after you wash car, or hose it off?  Is car outside in rain, or garaged?  What you described sure seems like classic coil pac issue.  Good luck.  

I keep the car outside. I don’t get that issues after washing the car. Only after it rains for a while I experience that issue. After a few days later the engine check is gone and the car runs fine.


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[Loren]

Water splashes up during a rain - I doubt you do that when you wash the car.

 

Coils packs can easily be tested with an ohm meter:

The resistance between terminal 1 and terminal 15 at 20°C:  0.3 - 0.7 Ohms

 

Likewise with the spark plug connectors:

Resistance: approx. 2 k Ohms

[Ahsai]

Are you sure your coils have no cracks? A lot of the cracks (black on black hair lines) are very difficult to see unless you examine every inch very carefully.

 

How old are the coils?

Edited March 4, 2018 by Ahsai

[sky217]

I was thinking more like water going down the air filter some how.


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[DBJoe996]

Replace all coil packs with the newer version.  You have cracked coil packs.  Just do it.  Water in the air filter is not the problem.  That would affect all cylinders and the car would run very badly, if at all.  Pull the air box, open it up and check that the drain hole is clear of debris in the bottom of the box.

[sky217]

Thanks everyone I will go ahead and do that.


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[joesouza]

Mine did the same thing, I changed all of the coil packs and plugs and it didn't help. I also began hearing a ticking noise so I had it hauled to the shop, they said the noise was the cam tensioner and it was normal noise as they age, and they claim to have identified a vacuum leak and changed the OAS which fixed it... for a day. I called the shop, they said to bring it back, and the engine exploded on the way... D chunk failure on the #1 cyl.

[judgejon]

Ouch.  

[sky217]

Mine did the same thing, I changed all of the coil packs and plugs and it didn't help. I also began hearing a ticking noise so I had it hauled to the shop, they said the noise was the cam tensioner and it was normal noise as they age, and they claim to have identified a vacuum leak and changed the OAS which fixed it... for a day. I called the shop, they said to bring it back, and the engine exploded on the way... D chunk failure on the #1 cyl.

That sounds really scary. I am reading this as I am getting all my coils replaced. Maybe I should just look into selling the car instead. Sucks I really love that car.



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[DBJoe996]

There is absolutely no correlation between changing out coil packs and having the engine D-chunk on one of the cylinders.  His engine had more problems to begin with.  Your issue is due to cracked coils getting wet and the engine running badly after it rains.  The new coil packs are a good thing and your car will run better.