[tadaska]

I'm completely flabbergasted by what I found when I removed the e-box. There is a drain-hole there but it has a grommet that impedes drainage. The bottom of the e-box has a sleeve that goes over that drain-grommet sealing it off and further impeding drainage. Also there is some rubber drainage hose that has wires underneath. Those wires are wrapped in insulating tape but I'm not sure that's a good enough protection against water. What is going on there?

I'm thinking I should remove that grommet from the drain, make cuts in the rubber sleeve underneath the e-box so it doesn't seal and cover those wires in some sort of sleeve made of continuous material so it deflects water.

What do you guys think?

[AWSAWS]

Your car looks a bit different to mine.
The ECU is inside a box in mine so it should never get water in it. The box is under a cowl in mine so water should never touch the box.
The cowl had additional raised protectors on mine so water should run off in all different directions. All that is under a bonnet.

[tadaska]

Originally Posted by AWSAWS

Your car looks a bit different to mine.
The ECU is inside a box in mine so it should never get water in it. The box is under a cowl in mine so water should never touch the box.
The cowl had additional raised protectors on mine so water should run off in all different directions. All that is under a bonnet.

My car has all those things too and I'm sure they provide some protection but when I removed it all there was water in the e-box well. So maybe that protection isn't 100% perfect. And there is a drain hose in there anyway...

[bishbosh]

What goes on under the ecu box stays under the ecu box

[tadaska]

Originally Posted by bishbosh

What goes on under the ecu box stays under the ecu box

I sure does

I think I'll leave the e-box "drain" rubber bits as they are and just drill another hole near by so that water that gets in there can drain easily without pooling up.

[rasa bmw]

sounds like the mg zt cdti...the water drainage plenoms get blocked,,you have to ram a suitably sized rod down to clear themmthey invented a mod for it that didnt block up,,loads of cases of drowned ecu,s...quite commen..by the way the mg dervs were de-tuned bmw 320d engines,,althougn turned round for fwd..130 bhp standard,,very iunderestimated cars,,can pick them up very cheaply and they are great driving cars with the 160 bhp map that a forum member wrote himself over on mgand75ownersclub

[tadaska]

It looks like there is a gap for water to get into the e-box well.

In the first pic the area of the rubber cover where the red arrows are pointing is almost flat. It's actually flatter than what it looks like in the pic. That image look is deceiving.

In the second pic you can see there is a gap not covered by the cowl.

And in the pic three you can see how rain water off the windscreen can run into that gap and then both ways - some into the drain that has those catch-baskets and some the other way and into the e-box well. If it's raining hard for a long period of time that e-box well could probably fill up to a considerable level and the water would be pushed up into the e-box and into the ECU if it's not fully watertight.

So I drilled a hole that hopefully will prevent this from happening. I smoothed the edge with a bit of sandpaper and covered it with primer the best I could using a q-tip. Will give it a coat of paint later and hopefully it will stop it from rusting.

[bee-ma]

Originally Posted by tadaska

It looks like there is a gap for water to get into the e-box well.

In the first pic the area of the rubber cover where the red arrows are pointing is almost flat. It's actually flatter than what it looks like in the pic. That image look is deceiving.

In the second pic you can see there is a gap not covered by the cowl.

And in the pic three you can see how rain water off the windscreen can run into that gap and then both ways - some into the drain that has those catch-baskets and some the other way and into the e-box well. If it's raining hard for a long period of time that e-box well could probably fill up to a considerable level and the water would be pushed up into the e-box and into the ECU if it's not fully watertight.

So I drilled a hole that hopefully will prevent this from happening. I smoothed the edge with a bit of sandpaper and covered it with primer the best I could using a q-tip. Will give it a coat of paint later and hopefully it will stop it from rusting.

What caused you to investigate this?

You are right about water getting into the e-box, my E90 suffered water damage to the ECU/DDE on three occasions, and each time I needed a new ECU!!

It is very puzzling why BMW have placed an important electronic unit right next to a water channel. To make it worse the metal area under the e-box is also enclosed so water cannot escape if it finds its way in. I also found on my car that the 'water outlet value' at the bottom of the e-box had also fallen out over time.

To fix the issue, i replaced the valve under the e-box, clean up any debris/water from the enclosure underneath and drilled a couple of holes (as well as painting the holes) at the bottom to ensure water never builds up in the area.

[tadaska]

Originally Posted by bee-ma

What caused you to investigate this?

You are right about water getting into the e-box, my E90 suffered water damage to the ECU/DDE on three occasions, and each time I needed a new ECU!!

It is very puzzling why BMW have placed an important electronic unit right next to a water channel. To make it worse the metal area under the e-box is also enclosed so water cannot escape if it finds its way in. I also found on my car that the 'water outlet value' at the bottom of the e-box had also fallen out over time.

To fix the issue, i replaced the valve under the e-box, clean up any debris/water from the enclosure underneath and drilled a couple of holes (as well as painting the holes) at the bottom to ensure water never builds up in the area.

I can't remember the exact reason why I removed the ECU box. When my car failed to start I was troubleshooting the problem and eventually a forum member here (Sensible_) pointed out that the ECU is not showing on the INPA. So my investigation around the ECU started and eventually I worked it out that the ECU is dead due to corrosion inside. I probably removed the ECU box because I like to know the condition of my car in those out of sight places. And whenever I work on something I'll sniff everything around it to see if anything else needs my attention. I think everyone who buys an E90 should open up their ECU and see if there is corrosion. Cleaned it up if there is before it's too late. And of course remove the ECU box and drill a hole or two. Paint it of course to protect from rust.

[bee-ma]

Originally Posted by tadaska

I can't remember the exact reason why I removed the ECU box. When my car failed to start I was troubleshooting the problem and eventually a forum member here (Sensible_) pointed out that the ECU is not showing on the INPA. So my investigation around the ECU started and eventually I worked it out that the ECU is dead due to corrosion inside. I probably removed the ECU box because I like to know the condition of my car in those out of sight places. And whenever I work on something I'll sniff everything around it to see if anything else needs my attention. I think everyone who buys an E90 should open up their ECU and see if there is corrosion. Cleaned it up if there is before it's too late. And of course remove the ECU box and drill a hole or two. Paint it of course to protect from rust.

Did you replace the ECU in the end and get it up and running?

[tadaska]

Originally Posted by bee-ma

Did you replace the ECU in the end and get it up and running?

Yes I did. Got a replacement ECU from BW Chiptune.