HELP identifying some weird wire !

[naut2k5]

Hey all, its me again, and something else I am unsure about 

About to rewire my engine earth straps (which I found out were on the wrong place anyway!  ) I know they go back on the metal plate on the rocker cover - my question though is that there was some other wire there - as you can see from the pic below it kinda came loose  and is now floating (it's the one down the middle of the pic) - Any ideas what this is guys? 

You'll prob notice that I have bypassed my heater matrix looking at the pic too !



Cheers all ! 

[Mr Blue]

you mean that white wire?

My fuel pump doesnt work if i disconnect mine. My mates does that too.

Dissconect it and see what doesnt work. probably something to do with the clocks

ohh and clean that engine bay you dirty bugger

[naut2k5]

Er, its the one that comes down from the top to the bottom.. about 5cms in from the top right ... kinda white but goes darker...

Would love to see what it does but my car hasn't been started since I fried my ecu! Just wanna know what this does so I can reconnect it, sort my earth straps and then whack my battery in and give it a go 

[Judderi]

It looks like an earth strap to me.

[naut2k5]

Eh? Another one! 

I thought these two are earth straps - you'll notice in the pics they are in the wrong spot though!



Compare the two earths on the above with this pic:



So, now im more confused, unless the wire (from my first pic) that came off is incorrectly placed too 

[Judderi]

The thinner wires in your pics may be earth wires but they are certainly not earth straps! Any bare metal part of your engine or chassis can be used as an earthing point for wires but you must have a heavy duty thick cable that acts as an earth strap between your engine and the chassis.

On my valver i have a braided flat squarish cable that goes from the negative terminal of my battery to the chassis - earthing the chassis. It then goes from the chassis over to the gearbox - earthing my engine.

By the looks of things the whole reason your ecu fried is because this thicker earth strap has broken loose. This meant the only route for the electricity to complete its cycle was via the ecu which is not designed to take high current thus it burnt out. You must sort your thick earth strap out before you replace your ecu or you will just fry it again. Leave the other small wires where they are as they seem to be working fine. You can buy new earth straps but a good upgrade would be some 4 gauge wire you get to power in car stereo amplifiers, thats what im gonna do shortly.

[naut2k5]

Hmm interesting , nice one dude!

So would having the earth wires loose cause this problem:

http://www.golfgtiforum.co.uk/index.php?topic=24781.0  [See reply from KKK]

Or is that only possible if the big duty earth straps are not properly connected ... Until yesterday the earth straps looked fine and were connected properly - The only problem, it seems, was the earth wires were connected to a rusty bolt (as seen in the pics above) and one of them broke off !

Jim

[Judderi]

I dare say the thin earth wires had nothing to do with your ecu blowing. Even thought the big earth strap was connected it may have not been making a good enough contact as you say it was all rusted up. I blame the strap! P.S re read my post above as i edited it later with more detail and you probably missed it.

[naut2k5]

Ah yea, I missed your update!

The earth strap on the engine only came loose yesterday (1 month since I had that initial problem - what can I say, im slow at doing things  ) So I posted this to find out what it was...
 
The only way the ecu may have fried is when the little earth wire came loose [It was actually completely loose until I noticed and corrected it while I bypassing the coolant flow for anothe problem I've had.   [Unless its more rusted than it looks !  ]

Then two days later the incident happened where the engine filled with petrol etc ...

The earth strap from the gearbox to the -ve terminal looks fine to me i think:





Where can I get those 4 gauge wire you speak of d00d - recommend any place of any good hifi store I guess!

Jim

[Judderi]

Your earth straps to your gearbox look fine to me too mate, no need to replace them really. So thats your engine earthed propperly. Have you followed that small wire that was origionally loose to see where it goes? Or does it disapear out of sight? Best bet would be to clean up the contacts with a wire brush or sandpaper or wire wool then re bolt them down, cleaning the bolt part too. It doesent matter that they are in a different place to normal as long as the contact is good. Also see if you can trace that thicker wire in your 1st picture.