ECU opening

Toby_HDi · Post by **Toby_HDi** » 03 Feb 2010, 20:30

Just a quick question now I've recieved the VN05Ns to repair my ECU.

Should I expect a gooey mess when I open it? What should I seal it back up with?

Off to practice with my new desoldering pump

addo · Post by **addo** » 03 Feb 2010, 20:52

It may be a function of ambient heat in Australia, but I found the perimeter gasket was rather like that foam strip around the edge of the door foam seals.

Getting the separation started was hard, I used 4mm flatblade screwdriver tips as wedges; wiggle one in, detach it from the driver and work another one in nearby.

Once the PCB screws were removed, the board was carefully persuaded free of the case - it was again well-stuck. I made an effort to not flex the PCB.

For resealing, I cleaned the gasket groove with paint stripper while the case halves were empty. I plan to use the round section rubber that's sold for making O-rings with. Socket face sealing and auxiliary bonding will be achived with Threebond #1211 which is a super-thin white neutral silicone sealant.

Toby_HDi · Post by **Toby_HDi** » 04 Feb 2010, 20:12

Desoldering pump works a treat! Tis electric so is like a soldering iron itself with a pump built in. Leaves a thin ring of solder behind that the new solder flows onto to secure the new component. I'm amazed, something that is actually quite well though out!

I didn't realise it was like a gasket, I thought it was sealed with sealant and screwed for extra security. Is this gasket type thing essential or would sealant be enough?

addo · Post by **addo** » 04 Feb 2010, 21:28

Stuff like the original seal, only keeps honest people out.

I reckon it's intended to create a moisture/dust barrier; in a damp country this might help reduce condensation forming inside the unit.

Using only liquid sealant, might make the box extremely hard to open again - plan for a possible need to revisit rather than thinking about the "here and now" only.

Post by **CitroJim** » 05 Feb 2010, 13:51

Opening the ECU box is very much as you say Adam. Remove the four big screws and carefully lever apart. There is a channel in the joint and this is filled with silicone. Once the box is apart you'll then see the board. To get it out, remove the fixing screws and the screws each side of each connector and gently lever the plug bodies out. These are stuck to the case with more silicone to make it all waterproof.

When you finally reassemble, use automotive grade silicone, put beads around the connectors and screw them home. Then put a bead in the channel of the box halves and screw it up tight. Job done.

This stuff will allow the ECU to come apart again Adam, no worries at all. I've done it...