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Discussion Starter · #1 ·
Hi Guys,

I have a 1992 E34 520i and I have a big problem. I will give you the history of the problem and there are two questions at the bottom if you can advise. Many thanks in advance

Started car this morning and it turned over but didn't fire.
Tried about half a dozen times and then took keys out of ignition
As I walked away from car (keys not in ignition) I could hear electrical buzzes coming from under the bonnet intermittantly. These stopped after 30 seconds
Opened bonnet but could not see any leaks or oil
Disconnected Battery in case electrical buzzing started a fire

Tonight I went back to car and removed fuse23 which is for the fuel pump
Reconnected battery
Started car and it turned over but didn't fire. Did this a few times
I then replaced fuse23 and started car. It turned over and started trying to fire . .
After a few attempts, it fired but i had to rev the engine to keep it alive
Car misfiring, smoke out of the back probably from unburnt fuel, car hunting and revs changing from 800 to 1400rpm.
After a few minutes it started ticking over nicely but then started misfiring again
Turned off engine and left alone for 30 mins

Looked around engine compartment and notice that the ECU which is housed in a bucket had almost 3 inches of water in it and it just touched the ECU. I drained water off by hose to bottom of the bucket but water was coming in to the bucket from underneath.
I redrained again, more water came in, redrained again and then removed ECU which did drip and release about an egg cup of water

Removed bucket housing and water had collected undeneath it and was coming in to the bucket from a hole at the bottom. redrained all the water and ddried it with kitchen roll until no further water came in.

I obviously have a drain hole that should feed to the wheel arches that is blocked and so it has made its way in to the ECU bucket from underneath. I will clear this drainhole so it never happens again.

My question is if I put the ECU in an airing cupboard for a couple of days and dry it out, will it work again or do you think it is not work trying and that i will need to buy a new one?

Does anyone know anyone in the South of England who will be able to do one cheap?

2 Posts
Discussion Starter · #3 ·

Drying it in an airing cupboard worked. Beemer fired up and ticked over beautifully.

I had the car jacked up today, sat on an axel stand, wheel off and removed the wheel arch protective shield off and the two drainage holes had been clogged up by four dropped bolt nuts and loads of grit.

I cleared debris with a wire coathanger and then put ECU back.

Once again, my problem with the Beemer was ultimately caused by human error (carelessness of a previous owner who dropped the nuts in a previous removal of the ECU) and not a design or part fault.

A very lucky escape me thinks. Thank you for your reply as I was a bit lost and living on a prayer

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