[boosted]

Im an electrical engineer in the food manufacturing industry. I work on all voltages ac and dc. Im 49 and being doing it far too long. Apprentice trained from 17yrs old.
Something strange has happened to your car and i dont think your being told the truth....
Short circuit. Basically live and neutral being joined together without a load inbetween them. Massive current flows. Enough to create an arch. If done at a battery with no fuse connection can cause harness damage i.e melting cables etc. Most jumpstarters have short circuit protection.
Jumping starting a car ignition should be off whilst clamping leads on. If it was jumped incorrectly with ignition on and lights on i.e those circuits turned on then the Individual circuit fuses should blow but a fuse is quite slow acting when compared to say household circuit breakers.
A spike is an overvoltage situation that is a short time period. Again high voltage higher current. Fuses should blow.
Ecus are very susceptible to spikes as the components are small and the circuits tracks are not designed to flow hi current.
Id say its either you alternator or something bad happened at garage...alternator needs testing...bench test can be done as if faulty could damage another car.
I got roped in looking at a go kart project ebay special awhile back..
12v motorbike battery on it.
Would start and run blow the headlight and cdi unit when revving (Basic motorbike ecu).
Headlight bulb was a 6v...little gokart was a 6v system lol.

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[boosted]

Where is the car? Id be looking for arch damage on the battery clamps?
Arch damage could be black residue that wipes away and or exposed fresh metal thats has arched.

Id get that alternator tested..to rule it out.

Where is the car?

Who was the repairer, theyve left you high n dry even if alternator and not there fault youd think theyd help abit more tbh.

Car went in running...id be mighty pissed tbh.



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[LJB]

Thanks boosted,

I’ve checked the fuses in the engine bay and all are ok. I still need to check the ones in the car.
With the alternator. The car wasn’t running and didn’t die. It was running fine and then wouldn’t start.
If it was the alternator that somehow failed during running with the ecu damaged the engine would cut out. On start up the tuner disabled the alternator until a certain amount of seconds at idle to help with start up. So could this rule out the alternator as a source of the damage?

The car is on my drive I’ll check for battery damage.

The garage was Yorkshire Car Restoration. He said he is willing to spend some time to look for my “electrical fault” as it couldn’t be anything he did.

 

[LJB]

Again forgive my lack of knowledge, but internet searching has thrown up a few possibilities. Welding took place on the drivers side inner wheel arch very close to the fuse box. Also on the passenger side inner wing very close to the ecu.
I’ve read that when welding close to electrical components that when welding the current can ground to these items more readily that the earth strap for the welder? Possible or no?

 

[LJB]

All fuses checked and ok. There are marks on the battery but I couldn’t say if they were new or just car clamp marks.
Another odd thing and this happened since I first went to it. I just thought it was due to a low battery but the alarm doesn’t arm and disarm normally. The doors lock/unlock but there is normally a double flash of the lights. Now there is are multiple flashes.

 

[LJB]

https://flic.kr/p/2o5hJHV

 

[LJB]

Could it be that the indicator bulbs are blown so not completing the circuit?

 

[boosted]

With a low battery and no running engine to top up youll get all sorts of electrical gremlins happening so i wouldnt drain it anymore as itll just get flatter.
I must admit ive welded lots and lots of cars and having always disconnected the negative of the cars battery ive never had a problem. If you got a bad earth on a welder no circuit no arch because no current flow. Ive done that when grinding back welds and then forgot to put the earth clamp back on..again ive not fried ecus or lights.
Your car the ecu regulates the alternator output. So start up would be fine and if over charging would be when the ecu turns alternator on...i dont know but something like a me ecu will have safety protection built into software and hardware...
I really dont know whats happened tbh.
Bulbs blowing can only be over voltage...


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[LJB]

I fully charged the battery to try out the lights. I’ll pick up some new bulbs tomorrow and see what happens.
Thanks again for your replies.

 

[boosted]

Ah ok. Keep us informed.
Im concerned you pop in repaired or new ecu and same thing happens without that alternator being checked.

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[LJB]

ME just suggested doing the first start monitoring the voltage.
I don’t know what’s involved with testing an alternator I’ll do some research.

 

[boosted]

Id tell about the bulbs blowing...and ask if they still want you to fire it up.

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[LJB]

For gods sake!!! Engine bay side of front inner arch repair!!! Even more annoyed now.

https://flic.kr/p/2o5vw6E

 

[boosted]

I think i should start a mx5 repair business...

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[boosted]

Then again....no....flashbacks to laguna blue s special...
(Repairs still holding up as i follow it on mot history).
Id clean with a wire wheel. Get some p38 to seal it, primer onit and some satin black to seal it all off.


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[LJB]

Unbelievable, there’s no sugar coating it now, an absolutely awful experience.
On the plus side Motorsport Electronics are covering the ECU under warranty. My ECU was “100% damaged” they have already sent out a new one and I should have it tomorrow.
Absolutely amazing customer service from them.

 

[boosted]

Did you tell them about the blowing bulbs?


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[boosted]

Spot on by ME.

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[LJB]

Yes told them about the bulbs, they didn’t have an answer or a reason. Im getting the alternator tested at Derby auto electrics. Hopefully I can get it off tomorrow and with them by Wednesday.
The daily is also in the garage with a fuel leak in the engine bay. After all this I don’t have the desire to work out in the cold.

 

[boosted]

Spot on mate. Its defo worthwhile getting it check.
£800 ecu at stake. ( thats a guess).
If nowt wrong with it.....
Something happened at the garage.....


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