Mr. Z

It has been dumping rain here (in Seattle area) and I've had three separate misfire incidents over the past couple of weeks. Each time, the problem has come after a serious downpour and has gone away after I've shut off the engine and waited a minute. I pull the codes and get "intermittent misfire, multiple cylinders" and "intermittent misfire, cylinder 7." The second-to-last time (Thursday), I pulled the codes that night and it said "ECU miscoded" (a problem I had about a year ago with a wet ECU).

Today, when I was just driving to the grocery store, it started to run VERY roughly. Got CEL flash for a minute, but then it went solid. Dropped into 2nd and drove home (2 mi.) VERY slowly. Haven't pulled codes yet.

I've seen the Audipages entry for cleaning the cowl and evap drains, but I'd like to see if the ECU is truly wet. How can I (easily?) get at it??

Also... The Cylinder 7 misfire seems oddly consistent. Hmmm... Thoughts?

Thanks in advance again for everyone's help. Hope you all had a great Turkey Day...

tonypai

It's right up against the firewall. Pull off the cover and the top of the ECU/TCM box is held in place by 6-7 screws. Take it off and look inside, most of the stuff will probably be wet. Use a heat gun to dry it out.

Be sure to check to see if it's wet in the passenger side footwell. there are a bunch of fuses and wires down there.

treat this problem seriously or you'll need a new ECU like me.

Mr. Z

So, I take off the various black plastic and rubber covers right by the glass on the passenger side of the engine compartment?? They've got some larger black screws holding them in place...

Should I take out/off the ECU or leave it in place and just open its case? When I had the issues about a year ago and they yanked it out, I looked inside out of curiosity. A ton of money for a single circuit board. Luckily, it didn't need replacing back then.

Thanks for the info!

tonypai

I'd open it up and dry it out. I don't think you need to pull the ECU out.

More importantly, you need to clear the 4 major drains. The shop snaked the two big ones in the middle for me. And I drilled two small holes into the passenger wheel well. For some reason water was collecting there.

Mr. Z

Opened the black plastic cover that houses the ECU and electronic goodies. There was about 1.5" of water at the bottom of the "V" in the lower chamber. There was some condensation throughout + a lot of condensation on the underside of the big, black plastic cover. Used syringe to pull out about 50cc's of water and then hairdryer'ed the rest. A bit of moisture at bottom, but otherwise all seems fairly dry.

Ran engine, but it doesn't seem improved. When I rev engine, there is a relay-ish "click... click" from what sounds like an area under the shifter. Am going to pull VAG-COM codes and post more soon. This "click... click..." is really concerning me.

Any thoughts?

tonypai

Post the codes, my problems went away when the ECU dried out.

Mr. Z

4 Faults Found:
16684 - Random/Multiple Cylinder Misfire Detected
P0300 - 35-00 - -
16691 - Cylinder 7: Misfire Detected
P0307 - 35-00 - -
16684 - Random/Multiple Cylinder Misfire Detected
P0300 - 35-00 - -
16691 - Cylinder 7: Misfire Detected
P0307 - 35-00 - -

These codes have been consistent across all of the times that the car has misbehaved over the past couple of weeks -- except that they resolved themselves in the past and only said "intermittent."

tonypai

But it would be for the 4 cylinders on one side of the engine. I would take a look at the #7 coil pack and maybe the spark plug.

roughyear

hey MR. Z... what was the outcome with this situation??