For all things Rover V8, the TVR Griffith and Chimaera and TVR T-Cars
The Black Box
Unlike the kind that’s secreted about aircraft, the ECU is painted black, but the ‘black’ part of the phrase means the dark arts, something unexplainable, weird, magic, and in may ways an electronic control unit (ECU) is all of those things and more. A television programme in attempting to describe what an integrated circuit (IC)) did showed the theoretical circuit of a transistor then said, helpfully, that there were more than three million of them in the IC. I
The ECU, arrowed, in an early model Chimaera. All pictures copyright RV8R.
assume I wasn’t the only one whom they lost at that stage. So when the ECU’s function is referred to in this brief article, please do not think it is meant literally.
Whilst its location varies depending on the vehicle it is fitted to, it is always in the same place: at the end of a thick bit of the loom. In the Range Rover it is often found under the driver’s seat whilst in TVRs the norm is that it will be hiding in the passenger footwell by the battery.
Do not mess with the ECU unless you have the relevant skills. It is easy to damage, and not only by rough handling. A discharge of static electricity can ruin an IC. If you don’t know whether you have the relevant skills, then you haven’t.
Disconnect the battery before doing anything with the electrics of any car. A plastic one, like a TVR, or those with aluminium panels, like the Land Rover, do not take kindly to fires. And nor, I would hazard to guess, do you.
Once removed you will generally find that the only thing holding the ECU to the rest of the car is a multi-pin plug. This should pull out without much effort. If it doesn’t then it might be better to get someone whom you can sue to do it for you.
Before opening the ECU I prepared a clean area on a worktop, put an A1 sheet of thick card down and worked on that.
The container can be opened with torx spanner and then it should fall apart after a gentle tap to reveal a circuit board, rather like the type you get in a computer. I always wear latex
medical gloves when working with circuit boards and also earth both wrists. I’ve never damaged an IC but I don’t know whether this is due to my precautions or despite them.
Don’t be worried if you are confused by all the gubbins on the board. Only those who think it is simple should be worried.
It is possible that the ICs are not properly seated. I’ve yet to meet anyone who has found one that is flapping around but I’m assured it is possible. So with insulated hands I gently pressed the ICs home. None moved. Next I examined all the connections under a jeweller's magnifying glass. This takes time to do correctly. If it doesn’t then you haven’t done it properly.
The circuit board and integrated circuits. The multipin connector goes to the right.
Then all that remains to be done is to turn the whole thing over and check the connections on the reverse.
The other side of the board consists mainly of soldered joints. A ‘dry’ joint can be difficult to spot without a magnifying glass.
If a fault is noticed, unless you are very sure of your skills with a soldering iron it is often best to admit one’s deficiencies and take the board to a specialist for repair or replacement.
Reassembly is easy although care must still be exercised. After advice I smeared the 40-pin contacts with contact cream because, I was assured, they were worth it.
The whole procedure provided a complete cure for my cutting-out problem. Not only that, the engine runs much better. There is more torque, the tickover has dropped from a bit over 1100 to 850 revs, the fuel consumption has dropped and, most importantly, the exhaust has become sharper and much more throaty without being any noisier.
On talking to various experts in the field of ECUs and electronics in general I was told that many of them advise people with a similar problem just to remove the 40-pin plug and replace it. As they do not hear from most again so they assume firstly that the problem has been rectified and secondly that the people were rude. I was told that my fault may have been a poorly seated IC, a bit of dust causing a partial short circuit or, most likely, a poor connection on the plug.
The far side
It must be remembered that the ECU is a very delicate item. It is very easy to damage and not only in the most obvious way of dropping it or dropping things onto it.
The integrated circuits work on such low current that even static can damage them. Whilst they are fairly robust given their limitations, these are set very low.
If you are not used to working on electronic devices and circuit boards, or have had no training in handling such things, then please seek advice and, most importantly, help.
ECUs are expensive items and damage is difficult to target. Therefore a simple breakage of a minor item might well give rise to a whole replacement.
If you are unsure whether you have the necessary skills to work on an ECU then it is extremely doubtful you have the necessary skills.
The ECU