Repairing the mounting plate for the K-Jetronic ECU's on the Testarossa                                                                                                                      January 12th 2008
Ever lift the lid on your Testarossa and notice the rusty plate that mounts your K - Jetronic ECU's. It stands out as it also locates one of the factory ID plates and is just at the bottom of the boot lid strut on the opposite side to your fuel filler.

Well I finally got sick of mine and decided it was time for a facelift.

The plate is held in place by two 10mm Nyloc nuts. Spin those off and then lift and slide the plate to get it out. You may have to unclip one of the large ECU looms to allow enough flexibility.

I hope yours looks better than this when you get it out!


Once you have the plate and ECU's on the bench, the next step is to remove them from the mount plate. The nuts are 8mm and you will need a deep socket to get to a couple as they are down low between the ECU's. Be really careful as they will probably be pretty rusty. There are three 8mm nuts holding each ECU in place. Even though I soaked my rusty nuts in penetrene, two out of six were seized and sheared off on my plate. Not happy, just another thing to fix.

Here's what my plate looked like once I drilled out the two pop rivets that hold the factory ID plate on. As you can see, the powdercoating has seriously degraded allowing the plate to rust away.

Next step was to clean up the plate. I tried sandblasting in my small cabinet but the powder coating that remained was too tough. I took to it with a 4.5" angle grinder and twist wire cup brush. That tore it off and then I went to the sandblasting cabinet for final prep work.

About an hour in total and it's nearly ready for primer and paint.

I had to grind the heads off the broken studs and then locate a couple of suitable 5mm threaded bolts the right length. I silver soldered these into the bottom of the plate. Will work as good as new with some nice new stainless nylocs and washers from the store tomorrow.

It was then time to prime the sheet. I used an anti rust metal spray primer, and then a spray putty over the top to fill some of the pitting left over from the rust affected areas.

This will dry overnight ready for painting with a full gloss black top coat tomorrow. I'm actually debating using a wrinkle finish black like the air intake system. This might end up being more durable than a gloss spray.

Whilst the paint dried, I pulled the two ECU's apart to check for damage to the tracks or boards from any leaking capacitors etc.

Here's the ECU board as it slides out of the housing:

You have to remove two screws and then separate the little black 'legs' that hold the rear of the board. Then the board 'folds' open, hinging on the grey ribbon wire. Be VERY gentle with this and try not to open it up too far. You want to look at the board components and it doesn't need to be completely open flat to do this.

Here's the two component sides of the boards. As can be seen, everything is in great shape after 19 years. No blown or obviously leaking capacitors or tracks that are showing any sign of overheating.

With the board out for inspection, give the plastic cases a thorough scrub in warm soapy water. Dry them well. If you have compressed air, blow them out and then leave in the sun to dry thoroughly before reassembling the boards.

Finished product ready to mount to the plate once the paint has dried.

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