ECU. do we need them?

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Homer
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Post by Homer »

fastandfurryous wrote: Plus... how much does an ECU cost? several hundred pounds. Considering that you can now buy a (much more powerful) motherboard for a PC for about £30, I think that's a bloody rip off.
How long do you think a £30 motherboard would last under a car bonet?

It might get you started twice.

I wouldn't even trust a £30 motherboard in a PC to last longer than a few months.
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Post by fastandfurryous »

Homer wrote:
fastandfurryous wrote: Plus... how much does an ECU cost? several hundred pounds. Considering that you can now buy a (much more powerful) motherboard for a PC for about £30, I think that's a bloody rip off.
How long do you think a £30 motherboard would last under a car bonet?

I wouldn't even trust a £30 motherboard in a PC to last longer than a few months.
Then you put it under the passenger seat.... or in an environmentally hardened case, and I have a £30 motherboard from 2001 operating as a computer in my garage. Works fine after 5 years. Although I was only making the comparison that electronics do not have to cost hundreds of pounds.

The point is (as made by bxbodger above) that a car ECU costs bugger all to manufacture, but costs you and I £200 at the very least. I think this is particularly bad as an ECU is a throw-away item.

Spend £200 on a brand new carburettor, and you can expect to be able to repair/re-jet/clean/overhaul it. Spend £200 on an ECU and when it goes wrong you have to bin it and get another.
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f00lzz
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Post by f00lzz »

[quote="bxbodger"]

Heres my Triumph engine-

Image[quote]

Ok so I can see it's a straight six with twin Strombergs but what car? A GT6 or a Vitesse maybe??
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Post by AnotherStuart »

Reading through this thread makes me realise why western manufacturing industry is in such dire trouble. We are all so used to our diet of cheap mass produced electronic products originating in the far east that we balk at the thought of paying 300 notes for an ECU. But... If you've ever dismantled a cheap consumer product like a TV set, portable radio or telephone then you'll have seen that they haven't just cut corners on quality, they've taken a large chunk of the straight as well. I acquired a pair of computer speakers that cost their owner 5 pounds brand new - let's just say that I wouldn't use them, although not actually dangerous their electronic design was so unbelievably crude that I'm sure a 12 year old hobbyist beginner could have done better. My (3 year old) washing machine contains a badly warped processor board made from compressed paper that looks like a refugee from 1970, and is "protected" by an ill-fitting plastic moulding. That's consumer electronics for you.

In contrast, a couple of years ago I dismantled a Ford EEC-IV ECU just out of curiosity. It immediately struck me just how well made this thing actually was (in complete contrast to the Sierra it came from, whose death was unrelated to the ECU) - it took me back to when I worked in avionics with its quality casing and a well made circuit board with the correct grade of components which was even fully waterproofed!

Do you seriously want cheap consumer grade electronics controlling your car? A £39.99 chinese-made ECU produced in multi-million quantities with hacked up, substandard software (I know, I know... but think how much worse it could be) that needs replacing at the same interval as oil changes and actually might not even last that long before the circuit board literally falls apart? And the sort of boards that they'd likely use to cut costs would disintegrate even if the ECU was in the cabin.

My point is,true quality is going to cost you. My company make a board which is not dissimilar in function and complexity to a vehicle ECU, and also operates in harsh environments. Using automotive grade components and sealants, we simply cannot make these boards for less than £140 each. And that's without a box to put it in, or development costs for its software, or final assembly costs, ...or any profit! The final cost to the customer is well into 4 figures - we make a 10% profit on that.
Of course, the vehicle manufacturers have economy of scale on their side but then they also have a longer distribution chain and therefore more overhead as everyone wants a slice of the profit pie.


£300 for a replacement ECU is not too bad, all things considered. The cost of the electronic parts used in its construction is only a small part of what it *costs* to make - unfortunately very few people have sufficient experience in electronic systems design and manufacturing to be able to tell the difference in process between an ECU and their Chinese MP3 player. It is entirely possible to produce ECUs for peanuts, but as I said above, they wouldn't last. With current, proven manufacturing techniques, ECU failures are simply not common occurrences at present considering the number of vehicles fitted with them over the past 20 years or so.
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Post by ACTIVE8 »

f00lzz
bxbodger wrote: Heres my Triumph engine-
Image

Ok so I can see it's a straight six with twin Strombergs but what car? A GT6 or a Vitesse maybe??
The devil is in the detail, and if you look below the picture in the signature section of bxbodgers post it all becomes clear.

bxbodger wrote:here's a C5 engine-

Image

Heres my Triumph engine-

Image

There's 40 odd years and 2 cylinders between these two, and although basic principals are the same the C5 motor is obviously going to be a whole lot more fuel efficient,reliable, cleaner and quieter- thats what the elastictrickery is for, but I know which would be the easiest to fix out of them (albeit a lot more regularly) ......and which one sounds best :lol:

Seriously, though, the past is a great place to visit on a nice Sunday afternoon, but we forget that its not that long ago that it was not guaranteed that a car would start on a cold wet Monday morning-something we now just take for granted- and how often nowadays does a desperate neighbour knock on your door for a jump-start??
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1989 BX17RD-231,000 miles and rising, and a 1968 Triumph Vitesse convertible-meccano car, straight six :vroom vroom!!!Oh,and a boring Kia Carens diesel mpv for her indoors....(but it does have the bosch HDI....)
Last edited by ACTIVE8 on 19 May 2006, 15:33, edited 1 time in total.
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Post by bxbodger »

Ok so I can see it's a straight six with twin Strombergs but what car? A GT6 or a Vitesse maybe??
Vitesse!! It looks simple and it is- the wires you see are basically all there are, and the point I was making is that it has nothing you could describe as 'electronics',unless you include the old Lucas electro-mechanical regulator, and is very easy to fix. But, it requires a lot more attention than a modern engine. Probably a lot more attention than most people are prepared to be bothered with now-you don't see the Saturday afternoon car fiddling that you used to, down every street.

With electronics, there's just no need for the constant fettling these old engines need, and they were just the same when new!!

Points need regular checking and cleaning, carbs need balancing,valve clearances need setting, there's none of that now so although all the sensors and boxes on the modern car have seriously added to the complication level, they just don't need the same attention!!
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Post by Kowalski »

If you think a £30 motherboard is poor quality, you haven't seen poor quality electronics. Any computer motherboard has to be a good quality PCB with nicely printed traces or it simply wouldn't work. Modern computer boards are complex pieces of kit, they have many traces and many layers, I have not seen one that I would call poor quality. I've seen poor quality components on motherboards and had to replace all of the capacitors on a motherboard before but the boards themselves have always been very good quality.

I saw a film made by Asus about one of its factories where boards were made, the reason they can get their boards down to a cheap price is because of the automation in the factory. The components they have to use are not cheap, but because all of the soldering is done by either a flow process or in an autoclave, there is very little labour involved, the automated processes produce very good quality boards.

The reason that an ECU is expensive is because the market will support the price, with a computer motherboard there is cutthroat competition, and massive volume. I can take the motherboard out of my computer and replace it with an equvilent board from 10 other manufacturers, that makes motherboards a commodity item so they are cheap.

There isn't actually anything specific in an ECU that makes it cost £300, there isn't some massive component cost, the microcontrollers in ECUs and the associated interfacing electronics are probably less than £20. The fact that it is "safety critical" and has to work in a "harsh environment" doesn't make it cost £300 to manufacture an ECU. ECUs are specific to particular cars with particular configurations. They come from a specific manufacturer and there are not very many sold, £300 is the price that the market will pay.

Cars are meant to have OBD connectors so Joe Public can connect his OBD interrorgator and find out why the little orange light is flashing at him. The thing about OBD is that there isn't a single standard for it, there are three different standards. Then there are the none standard extentions to OBD...
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Post by reblack68 »

Does my 1997 1.9TD Xantia have an OBD plug and, if so, where?

I work in an electronics factory and I'm not sure that we could get the bits on an ECU for £20. Having said that, we deal mostly in low volumes and don't have the buying power of a car manufacturer. There are program writing costs too.

Do ECUs really cost £300 anyway? I'm sure I heard about a Freelander that had an ECU replaced in one of those "substitute until we find the fault" procedures at a cost of £2000. They couldn't even put it back on the shelf when it turned out to be the problem because apparently they program themselves to work with only that vehicle as soon as they are plugged in.
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