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Its possible you fried the ECU when you jumped it. Its not really a good idea to jump start cars with sophisticated electronic control units.

Matt

The message from "**-**" contains these words:

Any real evidence for this apart from anecdote?

Electronics are usually very well protected and anyway the voltage from the donor car is going to be considerably lower than the host voltage because of the voltage drop along the jump-leads.

I'd say the battery was so knackered by being flat for a while that it wouldn't take a charge. Under those conditions, the voltage output from the alternator would be high, and could have caused those problems. If you leave the battery on an external charge for perhaps several days, it *may* recover. But I'd not worry about those problems until you've tried again with a charged battery.

& I've yet to hear any explanation as to why it's different to fitting a new battery. The only change from the old days is if you connect it back to front more things will care but that was always a foolish thing to do.

Why its...

"**-**"

What a complete load of crap.

How would the car know its being jumped? as opposed to having a new /charged battery fitted to it?.

As for sophisticated, car electronics are really old hat in new shinny boxes.

I really don't know why I bother. Having seen two Fiat Coupe's with popped ECU's after they'd been jumped I'd say it was a distict possibility.

But hey I only work for a major British sports car manufacturer amongst other things so what do I know (and for those semi-ignorant readers yes that is a retorical question)?

Was that from being jumped though or from somebody connecting the leads the wrong way round?

From being jumped, if you rattle the posistive lead against the terminal (numptys gettings a bit jumpy when you get a bit of a spark) it doesn't do it much good. Quite a few manufacturers are warning against jumping their cars. We give the option of supplying a trickle charger and charging port to constantly keep the battery topped up and avoid such a situation.

Blimey you'd almost have to deliberately badly design the ECU to care about that. & conventionally you attch the leads before you turn the ignition on.

Absolutely. Even if switched on, the only thing drawing current would be the regulated 5 volt rail - the output devices would be quiescent.

It costs pennies to protect an ECU from voltage spikes - and I'd expect this to be incorporated for normal running anyway. The DC on a car is very 'dirty'.

Rhetorical question or not, you do not know how to spell *rhetorical*

US Laptop = US Spell Checker

It was somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember "**-**" saying something like:

That shows nothing more than the piss-poor design of modern ECUs then, if they're not protected against voltage transients caused by intermittent connections. Even fitting a new battery could give rise to that, never mind jumping.

(for some reason I've not got the original of this, so sorry for the wrong attribution)

Did you strip the ECUs to find out what failed? Or more likely just take someone's word for it?

What 'British sports car manufacturer' uses Weber-Marelli injection, or are all ECUs just black boxes from Mars?