I was wondering if anyone has had any problems with heavy downpour rain and some stuttering and loss of boost. This has happened maybe 4-5 times, and most recently happened this past weekend (had tons of rain which we have not seen in a few months). I got onto the highway, and went wot in 3rd gear, and the boost climbed then cut out at .3-.4 bar and the car started stuttering very hard. I released the gas and accelerated slowly and the car drove fine...then went wot 2 more times, and it stuttered violently again...no dash lights at all. I then drove home slowly and when I finally got close to home (10 mile drive), I went wot again, and everything was fine. Also, it was not a loss of traction, so not a psm issue.

I do have the EVO intake and was wondering if maybe water got in there and got all over the MAF. Maybe since I drove a while the heat evaporated the rain, and that is why everything was fine? Anyone?

 

If it's only happening during a rain fall then its not the plugs....
Could be the Vflow....

 

My S4 had issues the same issues. Turned out to be the uneven cooling of the exhaust, disrupting the flow. Same thing?

 

Yea, it only happens when it is pouring rain out. If it is a light rain, I never have an issue.

As for the uneven cooling of the exhaust, why would that cause it to stutter?

 

i had the exact same issue maybe 3-4 times all when driving the car after heavy rain.

i noticed that after even a carwash the evo box collects some water/soap.

if you go WOT i think their is so much suction in that box that the water gets slightly sucked into the intake and hits the maf and it cuts out.

the feeling i would describe when it cut out was like when you hit the fuel cutoff.

no lights on dash as well.

 

Exactly!!! Perfect analogy on how it feels. I wrap a plastic bag around the opening of the Evo intake when I wash my car, because of the pressure of the hose getting water in there.

At least I am not the only person experiencing this. Guess it is normal after heavy rain then.

 

I'm not a genius, or smart or anything like that but, the cats on my S4 would get cooled during heavy rain and would cause turbulence in the flow of air inside of the exhaust. Just think about the reasoning for wrapping headers. The hotter the exhaust gasses the faster they travel. If the exhaust temperature is different mid way thru the exhaust system, a back pressure or change in speeds with in the system could cause the flow to be distrupted. I remember asking Audi or APR about this when I first experienced the issue. The MAF issue sounds plausable as well. Good luck!

TXGold

 

This EXACT thing happened with my car after a moderate to heavy rain after installing the Evo V-flow. I figured out that water was collecting at the bottom of the intake box and going WOT created so much suction that it literally sucked some of that moisture through the air filter and onto the MAF. This caused it to stutter, in my case violently. I noticed that my intake did not have any drain holes in the bottom like the stock unit did. I drilled two 3/8 holes on the bottom of the Evo intake (one at the far right upper corner right under the opening, and the other about 4-5 inches to the right of the air filter). Problem solved and I have never had this problem since, even in serious down pours. I bet this will fix your problem. Good luck.

 

This EXACT thing happened with my car after a moderate to heavy rain after installing the Evo V-flow. I figured out that water was collecting at the bottom of the intake box and going WOT created so much suction that it literally sucked some of that moisture through the air filter and onto the MAF. This caused it to stutter, in my case violently. I noticed that my intake did not have any drain holes in the bottom like the stock unit did. I drilled two 3/8 holes on the bottom of the Evo intake (one at the far right upper corner right under the opening, and the other about 4-5 inches to the right of the air filter). Problem solved and I have never had this problem since, even in serious down pours. I bet this will fix your problem. Good luck.

 

Valley996TT, thanks for the info. I will look to see if I have any drain holes tomorrow, and if not, I will drill two small holes as you did. I had the same symptoms, and thought that my car going to stall on the highway.
Once again thanks!