06 Golf GLS runs real bad after rain
 

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 seems that something is getting wet and causing a problem but I cannot figure it out. I sealed the coil connections, checked wires etc. Can't find the problem. When this happens, I get check engine code that says "cylinder 3 misfire", or some other cylinder misfire. Anyone have this same problem or know what may be causing it???

Welcome to the forum. Attachment 2356


You doesn't say which error code but I assume its.









As taken from my new https://volkswagenforum.com/forum/ge...oftware-34973/


https://volkswagenforum.com/forum/ne...gnature-34185/

06 Golf GLS 2.0L runs rough when it rains
 

Thanks for the reply, but all this seems irrelevant to my problem because it goes away after the engine warms up. 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. Something is getting either wet, or moisture is getting into something enough to cause the engine to run really bad only when the engine is cold. 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. I haven't actually looked yet but I suspect that the coil may have a crack in it. I have seen other threads where people have had a similar problem, but many of them say their car won't start or is very hard starting too. The coil was the problem for most of them so I suspect it's the same for my car. I will check the coil next and I will reply to the post if this corrects the problem.Thanks again for the reply!

It sounds like water ingress in the ecu if its worse after rain which you can Google. Check the drain vents aren't blocked with leaves and crap?

Hi Grbullets, I was just wandering if you had any luck with the misfire-after-rain problem? I have the same issue on 2004 Golf 2.0. exactly as you describe. btw it's been like this for 3 years, only and always after heavy rain.

Sorry for the delayed response but no, I have not figured it out yet. It's been way too cold and snowy to work on the car, but now that we're getting a couple warmer days, I'm trying to find the problem as it has been getting worse. Actually,I now have a no start issue. It will not start and stay running. I tried a new coil which I thought might be the wet running problem, but that didn't do anything. My daughter was driving it when it ran low on coolant due to a crack on the thermostat housing. She said the temp got real hot, (almost to the red) when she shut it down. Now I have this no start issue. It will start but it dies out after a second or two. I'm pretty sure its not a fuel issue as it will not run any more when spraying starting fluid into the throttle body. It just starts and dies...I do have a couple MIL codes that point to mass air flow sensor, and another throttle actuator and actuator motor circuit. So now I'm looking for some help with this issue. If I find the wet problem I will certainly post it...

Please post the new error codes?

I did start a new thread with the codes, but this is what came up. PO102 (mass air flow input), PO638 (throttle actuator range bank 1), P2101 (throttle actuator motor circuit) and PO321 (engine speed input circuit)..I suspect that the throttle codes were tripped during the numerous times that we tried using starting fluid to see if the engine would run for more than 2 seconds, but not sure about the mass air flow and engine speed.. Right now the car will not run for more than a second or two. It got pretty hot the other day when my daughter was driving it and now it won't run. It will start every time but dies right away after a second or maybe two..I did put a new coil in it. No change. I don't know if the engine getting pretty hot did something to one of the sensors or what, but before it got hot it would only act up after a hard rain and then would run great once whatever it is getting wet dries up..Now we have a no run issue.

Grbullets:
Wiki says: "The air mass information is necessary for the engine control unit (ECU) to balance and deliver the correct fuel mass to the engine." So, just thinking, if your MAF was damaged/affected during overheat event, then it maybe telling the engine wrong info about how much fuel it needs. And it does not run. I'm certainly not an expert on MAF, but it maybe worthwhile to replace this first and see what happens. I think these sensors are pretty inexpensive. BTW, thanks for your earlier replay to my question about the rough-after-rain issue. Best of luck!

GreatPlain

You can try this to test MAF. I came across in another forum: "Do not remove the MAF from its housing, just unplug the plug connector. The ECU will then replace the faulty signal with a default value. If the car has more power or is unchanged, the MAF is definitely bad. If power is significantly worse, the MAF is good or marginal." So ECU uses some "default value" if MAF is not present at all. Which may be helpful to your troubleshooting.