Burnt out ECU???

[davetherave1970]

Anyone think this is possible?
Fitted a new alternator last Wednesday and all seemed fine.
Went on a spirited drive out on Monday morning which lasted 4 hours!
Used the Griff on Tuesday afternoon for a 60 mile drive....but didn't make it home! Car just cut out and the MIL light came on. Had a slight burning smell too
Today its at Hilton & Moss and the ECU has two points burnt out.
Could a faulty alternator do this? Hilton haven't found the cause yet. They don't want to put another ECU in only for it to melt also!
Anyone had this problem from an alternator?

Its just me thinking - coincidence?

[Loubaruch]

There are a few on here with specialised knowledge of the Lucas ECU, I am assuming it is the Lucas 14UX in your car hopefully one will be along with some info.

To determine the cause of the failure the actual bits burnt out should give a clue. There are numerous inputs and outputs terminating in the ECU so identifying the parts linking to particular ins/outs may give an indication that something outside the ECU has caused the problem. If the alternator volts were very high I suppose that could cause it to burn up but measuring alternator volts would be straightforward.
Best of luck, a nasty one

[MPoxon]

I would be surprised if it was the alternator. Should the fuses not protect the ECU from a faulty alternator?

Is it possible that something was disturbed when changing the fuel tune resistor?

[davetherave1970]

I think I may have disturbed something in that area when changing the alt as I discounted the battery.
I'm sure Hilton & Moss will be in touch tomorrow or Monday to let me know their findings!
Costly time: -
New Racing Reds shocks four weeks ago.
New Alt last week.
New ECU this week.
Tyres, wheel bearing and discs and pad for the eurobox next week

[Gatecrasher]

Had the same thing happen to me. It was caused when the ECU case touched one of the live terminals on the fuse box. It melted a few pins and burnt some tracks on the PCB. It's not something that would be caused by the voltage regulator packing up in the alternator.

If you get any 14CUX ECU from a Landy on eBay or a scrap yard, take the chip out, solder in a chip carrier from Maplin and put the chip out of your old ECU in you should be up and running again.

[MPoxon]

Nightmare.... it has been an expensive month for you!

It is possible something got dislodged as you say. If my birds nest of cables in the passenger footwell is anything to go by then it could easily happen.

Best of luck fella I hope Hilton & Moss manage to rectify it quickly and cheaply.

[MPoxon]

What was the final diagnosis in the end.... was it the ECU like you suspected?

[davetherave1970]

Two tracks on the ecu were burnt. Two earth wires to it were also melted together.
They stripped back the loom and replaced as much as they thought necessary.
No other faults were found so they can only guess that something touched the battery.
I think i'm lucky it didn't turn into a fire ball!
They showed me the burnt ecu and it still smelt.
Collect the car today.
I hate it when there isn't a definite answer to a fault. I now have the worry it'll happen again

Edited by davetherave1970 on Thursday 12th May 22:15

[MPoxon]

I know what you mean about not having a definite answer. It may be worth carrying a small fire extinguisher in the car just to put your mind at rest. I have been meaning to get a cheap one from the bay for a while now. I am not sure it would be any good for the failed fuel pipe issue which has claimed a number of Griffs but it should be able to tackle an electrical fire if caught quickly enough.

Hopefully it was just a case of bad luck where something has been dislodged when the alt was fitted and all is well now.