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Misfires after heavy rain. (04 Golf, Jetta, any 2.0 Engine)

Misfires after heavy rain. (04 Golf, Jetta, any 2.0 Engine)

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  #1  
Old 12-19-2016, 09:08 AM
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Default Misfires after heavy rain. (04 Golf, Jetta, any 2.0 Engine)

Hello,
I was wandering if anyone had any luck fixing the misfire-after-rain problem on a 2.0 engines. It seems to be a pretty common problem. There are a number of posts on this subject, and a lot of suggestions (from plugs, wires, coil, corroded grounding wire, to replacing the ECU?). However, I could not find any cases where someone was able to fix it. Here is the description from drbullets from 7/2016 which describes the symptoms in excellent detail:

"My 06 GOLF GLS 2.0 will run really bad after a hard rain. After about 15/20 minutes of running it will run normal.It only happens when we get a good rain and the engine is cold when it rains. The plugs/wires have been replaced not all that long ago. There are no leaks around the head/intake. The engine runs just fine when it's cold too as long as it's dry, this problem only happens when it rains hard. It does not happen if the car is hot and running and it rains. It chugs and runs very rough, but as soon as whatever is getting wet dries up, it runs perfectly fine. I believe the MIL code was PO303 (cylinder #3 misfire) but I do remember seeing a code saying cylinder #1 misfire as well, so it's random. "

If anyone had success actually fixing it please chime in. Many great thanks in advance! Happy Holidays.
 
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  #2  
Old 12-19-2016, 09:23 AM
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WD40 is good for water problems.


VAG Error Code: 16687/000771/6352
EOBD II Error Code: P0303

Fault Location:
Cylinder 3 - Misfire Detected

Possible Cause:
Malfunction Indicator Lamp (MIL)(K83) active.
Lack/loss of power.
Hard start.
Engine hesitation.

Wiring/Connector(s).
Ignition system.
Fuel injectors.
Fuel pressure.
Running out of fuel.
EVAP canister purge valve.
Evaporative emission system.
Low compression.
Base engine problems.
Engine Control Module (ECM) damaged.

Special Notes:
This feature search for engine misfire in a specific cylinder. Most of the time the cause for a misfire is a lack of combustion in a cylinder due to absence of spark, poor fuel metering, or poor compression.

Tech Notes:
The P0303 code means that the cylinder 3 is misfiring or is randomly misfiring. Start by checking for intake leaks an if no leaks are found the next step is to replace the spark plugs on cylinder 3. If the problem persist more tests needs to be done to diagnose problem.

Description:
When a misfire occurs, engine speed will fluctuate. If the engine speed fluctuates enough to cause the Crankshaft Position Sensor signal to vary, the Engine Control Module (ECM) can determine that a misfire is occurring.


 
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  #3  
Old 12-19-2016, 12:21 PM
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Keith, thanks for replying. "DW40 is good for water problems". I agree. Not sure how does it relate to the question, though. Were you able to fix, or do you know of, or read of anyone who actually been able to fix the "misfire-after-rain" problem? There is a good number of suggestions out there - it maybe plugs, or wires, or coil, etc..? But the question I have - has anyone actually report fixing the problem. Something like this - it was misfiring-after-rain, then we did something, and it stopped misfiring.

Maybe this is a "non-fixable" problem. We just have to live with it

thanks again
 
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  #4  
Old 12-20-2016, 08:26 AM
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The title is Misfires in heavy rain that's why I suggested WD40.

You need to get your motor scanned (preferably with VAG-COM\VCDS) for any error codes logged in the ecu and post them, that will save a lot of guessing.
 
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  #5  
Old 12-20-2016, 03:39 PM
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"code was PO303 (cylinder #3 misfire) but I do remember seeing a code saying cylinder #1 misfire as well, so it looks random"
 
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  #6  
Old 12-20-2016, 04:32 PM
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Keith, thanks for replying. Just to clarify - the post title is "Misfires *after* heavy rain". Not *in* heavy rain. That's the whole point. Car runs great in the rain, or any other time. Problem occurs only *after* the car was sitting, heavy rain fall, and then you try to start it up after the rain.

thanks!
 
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  #7  
Old 12-21-2016, 07:35 AM
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There is a code for Multiple Cylinder(s) - Misfire.


VAG Error Code: 16684/000768
EOBD II Error Code: P0300


Fault Location:
Random/Multiple Cylinder(s) - Misfire Detected/Upper Limit Exceeded/Implausible Signal

Possible Cause:
Malfunction Indicator Lamp (MIL)(K83) active.
Lack/loss of power.
Hard start.
Engine hesitation.

Wiring/Connector(s).
Air Intake System leaking.
Fuel Supply faulty.
Injector(s) faulty.
Ignition Cable(s) and/or Spark Plug(s) faulty.
Ignition coil(s) faulty.
Exhaust Gas Recirculation (EGR) Valve (N18) stuck/open.
Camshaft Position (Hall) Sensor (G40) faulty.
Low compression.

Possible Solutions:
Check/Replace all faulty Wiring/Connector(s).
Check Misfire Recognition.
Check Air Intake System.
Check Fuel Supply.
Check Injector(s) and Injector Sealing.
Check Ignition Cable(s) and Spark Plug(s).
Check Ignition Coil(s).
Check Exhaust Gas Recirculation (EGR) Valve (N18).
Check Camshaft Position (Hall) Sensor (G40).
Check cylinder compressions.

Special Notes:
This Diagnostic Trouble Code (DTC) indicates that one or multiple cylinders are misfiring, but the Electronic Control Unit (ECU) fails to identify the cylinder.

Tech Notes:
The P0300 code means that a cylinder(s) is misfiring or is randomly misfiring. Start by checking for intake leaks, intake gaskets are common caused of multi-cylinder misfiring. If no leak are found the next step is to replace the spark plugs. If the problem persist more tests needs to be done to diagnose problem.

When is the code detected?:
The control module monitors the crankshaft speed and has detected a misfire condition.

Description:
When a misfire occurs, engine speed will fluctuate. If the engine speed fluctuates enough to cause the Crankshaft Position Sensor signal to vary, the Engine Control Module (ECM) can determine that a misfire is occurring.
 
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  #8  
Old 02-22-2017, 10:46 PM
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Default Misfire when wet..

I had NO codes showing until whatever it is that's getting wet causing the engine to misfire gets wet and the engine runs like crap..I will then get random misfire codes. Could be cylinder #3 one day and then Cyl #1 or 2 or 4 the next time it rains..There is no rhyme or reason to the misfire codes. The engine runs smooth as a baby's butt when it's warm. Once whatever it is that's getting wet dries up, the engine runs great. There are no head gasket leaks, no vacuum leaks, the coil and wires are fine and nothing looks wet..With so many people having this issue, someone must know whats happening...I sure hope someone posts the answer here soon because I'm about to drive this VW off a cliff..Somebody PLEASE HELP!!!!!
 
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  #9  
Old 02-23-2017, 12:13 AM
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Originally Posted by Keithuk View Post
WD40 is good for water problems.


VAG Error Code: 16687/000771/6352
EOBD II Error Code: P0303

Fault Location:
Cylinder 3 - Misfire Detected

Possible Cause:
Malfunction Indicator Lamp (MIL)(K83) active.
Lack/loss of power.
Hard start.
Engine hesitation.

Wiring/Connector(s).
Ignition system.
Fuel injectors.
Fuel pressure.
Running out of fuel.
EVAP canister purge valve.
Evaporative emission system.
Low compression.
Base engine problems.
Engine Control Module (ECM) damaged.

Special Notes:
This feature search for engine misfire in a specific cylinder. Most of the time the cause for a misfire is a lack of combustion in a cylinder due to absence of spark, poor fuel metering, or poor compression.

Tech Notes:
The P0303 code means that the cylinder 3 is misfiring or is randomly misfiring. Start by checking for intake leaks an if no leaks are found the next step is to replace the spark plugs on cylinder 3. If the problem persist more tests needs to be done to diagnose problem.

Description:
When a misfire occurs, engine speed will fluctuate. If the engine speed fluctuates enough to cause the Crankshaft Position Sensor signal to vary, the Engine Control Module (ECM) can determine that a misfire is occurring.


Shall I just get 15 cans and spray the whole engine down with WD40 since I have no idea what is getting wet or where it is??? If someone can let me know what could possibly getting wet enough after a good rain that it would cause the engine to misfire or sometimes not start at all until it dries up...I'll be happy to drown it in WD40...
 
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  #10  
Old 02-23-2017, 12:26 AM
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Posts: 14
Default Wet Misfire

I just saw a post from someone with Golf having a similar problem..After replacing just about every sensor and testing everything possible, they discovered that water was getting into the car through the firewall and getting electrical connectors and relays wet under the steering column. I'm definitely going to look into this as I just can't see anything under the hood getting wet enough to cause the engine to misfire, but this makes a whole lot of sense since it only happens after a hard rain. Light rain doesn't seem to affect it most of the time, but every time it rains hard the engine will run like crap until something dries up...I'll let y'all know if this is the mysterious culprit that nobody can seem to figure out..
 
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