Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing Waterlogged ECU

A good diarrhetic, but not as a suppository!

ACF is a brilliant product and I use it a lot but IMHO I would not use it on a circuit board or my ECU. It is after all a sticky lubricant that may attract contaminants over time compromising it’s dielectric strength. If you want to protect a circuit board from atmospheric moisture, clean it and use a dedicated conformal coating spray.

Not just Morgans but on bomb proof MX5's

On cars up to 2005 the ecu is in the passenger foot well.

The hood has a rain rail that sends all the water that hits the hood into the rail and that water is dropped at the seat belt towers inside the car.

It then goes down drain tubes and exits behind the rear wheels.

Mazda do not advise owners to clean the tubes once a year. Therefore people do not do it.

The water then goes down behind the seats but under a waterproof carpet into the foot well and soaks the ECU.

On 1998 to 2005 cars the alternator voltage regulator is in the ecu.

So the first you know about it is when the battery gets 19 volts for a week.

New ecu about £2,000 but in most cases a dry and hair dryer on the ECU fixes it.

Yip bomb proof those MX5's are!!!!!!!!!!!!

Roger, what I suffered was a lot more than atmospheric moisture, it was swimming in rain . One of the advantages of ACF-50 is that it isn't oil based and isn't therefore sticky. They actually recommend it for use on PCBs and electrical connectors, especially in the marine environment (and driving a Morgan in the rain has been likened to sailing before now ) I believe that the RNLI use it, which is a pretty good endorsement.

Indeed...but actually surprisingly little heavy rain. I think a bag of silica gell inside the box would do no harm at all.

It is odd that on a 2009 Roadster all the fuses, relays and other electrical stuff is to be found in a nice, waterproof and easy to access box. Yet on other more recent models MMC still put fuses uand relays behind the dash. Wierd!!

Mercedes SLKs also have most of the electronics in the pasenger footwell but are not waterproofed in any way. This means that if even a few cm of water gets into the car it is a writeoff. I have a friend who lives by the Thames and was caught by the flooding this winter. His E-type and his wife's 3 year old SLK were in the garage and they couldn't get them out.

After the deluge the Jag needed new silencers and carpets. Easy.
The repair cost for the Merc was estimated at £27K: ECUs, seat controls and motors, carpets and upholstry. Scrap.

A Mog would have been like the Jag.

Funny (or not so) topic of familiarity to me this one.

With smart Roadsters (Leaksters) not the engine one but another ecu the SAM unit was sited under the wiper tray which had a habit of leaking ( when it filled with water due to blocked drain which was substantial in diameter) and poorly assembled pinched seals did not help, this sam unit is inside the car just above the drivers knee it effectively is a fancy fuse box come input output unit.

People have taken to protecting the multiple circuit cards inside with various coatings as it's not only direct water intrusion but condensation from a saturated wet insides (various paths for water to get inside the cabin on none sorted roadies)

My advice if you are at all likely to use a car in the wet or even park it in the wet is to be proactive where the electronics are concerned and protect them before it becomes an issue.

We do see quite a few Mogs advertised as "garaged and never driven in the wet" it's a car it should function okay in the wet it's not my older brothers first mini he had where the wiring had gotten that damp it fell apart in his hands.

Maybe expected in the 70s not now though

At least MMC wiring looms are not fabric wrapped.....

By all means give a ACF a go but it might be prudent to conformal coat first. I suspect the PCB's in the RNLI’s equipment along with other equipment designed for harsh environments would have been ruggedized in this way when manufactured. Common practice in the marine aerospace and defence world but not the commercial.