How to open your ECU

[Tractor Dave]

There are a few guides on here but all the pictures have gone so I thought I would make a new one. Thanks to Newsh who talked me through the process. Once you know how it’s quite easy.
1. Remove your ecu. This is located in the left footwell up behind the airbox. There is a tab holding it up there (or there should be) and once squeezed it drops down. Lift the metal hinge to remove the connector and remove the vac pipe.
2. Take the ecu inside and place on a nice clean surface away from your cup of tea!
Next fold up these tabs to remove the metal cover using a flat blade screwdriver and pliers.

The cover then lifts off.

3. Next step is to separate the two circuit boards by the ribbon tape. First remove this nylon tag using a small flat blade screwdriver.



And using your fingers pull the boards apart to release these two locking pegs.


4. Now the fiddly bit. The top board is held in at the connector by clips either side and one top middle. Using small flat blade screwdrivers press in the two side tabs whilst simultaneously pressing in the middle down. This allows the top row of connector pins to move back slightly and release.


Then pull the top board back away from the connector until the pins clear the opening.

Now you can fold it open and see what’s inside.


The two important chips are the ones covered by the yellow plastic bits. If you have these covers then that’s good news as your chips are probably socket chips rather than solder in. To remove the covers, lever the sides out using a small flat blade screwdriver.

If your chips are socket you can carefully lever them up using a thin flat blade screwdriver. Take a picture of your chips before you remove them. The lower chip here is the charger chip sometimes marked LDR and the upper chip above is the fuel chip sometimes marked MOT. The chips have a little cut out on one side so you don’t get them the wrong way around. Take care when removing and refitting as the pins bend very easily.
I found that using a long screwdriver helped replacing the chip as the pins need gentle teasing in on replacement.


If you don’t have sockets then your new chips will need to be soldered to the board. If you haven’t done this before I suggest you get your local tv repair man to assist you. It might be a good idea to get him to solder in the female socket adapters for you (a few pounds on eBay) then you can swap your chips yourself easily.
Putting it back together is quite easy, reverse of above. Just be gentle returning the top row of pins back into their slot. When you get them in the right position they just slide back with a nice click. Don’t forget to press the board pegs back together and push the nylon tab back in.


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[K Simmonds]

Great guide Dave, couldn't have written it any better myself.

I will second getting a professional to solder in the female sockets and I work with PCB's as a sound engineer, it's a job that requires a serious amount of experience and skill with a specialist soldering iron. Given what these ECU's are now worth I simply would't take the risk of doing it myself and a Pro won't even want that much money.

[sal_s2]

I think every mapper solders in the female sockets for ease of fitting chips. Were yours the original ones Dave?

[Tractor Dave]

No, don't think so but going back oe.

[johne]

2. Take the ecu inside and place on a nice clean surface away from your cup of tea!

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You need the surface to be slightly conductive to avoid any static build up. Sheet of brown paper, cotton tea towel are fine, bubble wrap, sheet of polythene, plastic covered table cloth etc. is a definite no no.

When you get to the point of actually changing over the memory chips an anti-static wrist band or a careful routine of grounding yourself to the circuit board repeatedly during the process is sensible insurance.

[Tractor Dave]

Good point John. My boy does a lot with computers and has an earthed wristband he wears whilst doing the internals. Nylon carpets and trainers are not good!