Anatolych

It first happened 2 weeks ago, when my car started misfiring on 2 cylinders. My mechanic replaced 2 injectors and it started working fine, however the check engine light was still on. He said it was because the oxygen sensor was ruined by too much gas in the exhaust system. But it would drive ok for a few weeks. Last night, it happened again. My ECU gives out knock sensor, misfire of 5th cylinder, and an unknown code (04-12).
At the same time, I found out that my passenger side carpet is soaked wet. I remember my girlfriend complained the first time this happened about water dripping, but this was during a big storm and I did not pay too much attention to it. But now that I think about it that was the first time I have used AC this season, and the second time was last night. Knowing that the ECU unit is under the dashboard, it is possible that the ECU unit got some water.
Did anybody experience anything like this? Why would there be so much water generated in only about 1 hour of AC working? Any thoughts about fixing this?

Sir Nikon

I noticed that in my car the carpet on the passenger side was getting wet due to one of the windshield seals coming off. Check the seals around all the glass, door, etc. and make sure it's on there nice and snug.

Also had this same problem in the back too. Turned out the struts were leaking all over the interior of my car. Had to pay to have it cleaned because mold began to grow.

njmaxseltd

iTrader: (19)

Your A/C drain line is clogged.

Dave Holmes

Exactly what njmaxseltd said. You can spot it from under the passenger side of the car, in front of the passenger floor pan. It'll look like a hose pointing down and not connected to anything. If that is clogged, the water the AC removes from the air will have no place to go, and it'll leak on the passenger side carpet. You'll need to unclog it somehow (I haven't had to do that to a Maxima yet, maybe someone else has the particulars).
You'd be real surprised at how much water the AC will remove from the air in an hour! Have you ever let your car idle for 5 minutes with the AC on and then see the puddle under the passenger side (well, if your AC drain line is plugged, maybe not)? I would think it could easily soak your floorboard in an hour.

Dave

Anatolych

Thanks, all! I think this was in fact the AC! If your passenger carpet is wet, I strongly recommend clearing the drain immediately. If you let it go for too long, chances are water will drip onto ECU unit. I don't think they have desined it for underwater operation. May be they should have...

csherm

On the hottest muggiest day in Boston this summer my a/c starts dripping too. 15 mins later I'm idling at a light and my engine starts knocking, almost stalls, foul milky smoke comes out the exhaust. I start freaking out, but the problem goes away. 2 weeks later, same knocking but this time the CEL goes on. 0701 "multiple cylinder misfire". Freaking out again ...

Question: is it possible these two problems are related? It's quite a coincindence that we both have the same two issues. One theory I've thought of is water in the gas, but I can't explain how the a/c condensation makes it into the combustion chamber.

Checked my sensors, they're all funtioning properly. Gonna clean my MAF and throttle body, and unclog the a/c drain. Any other suggestions?

maxNYC

iTrader: (1)

check for dried residue on your ecu. a wet ecu will give you the symptoms you described.