Car not turning over

Hi Paul,
all your symptoms sound like a problem with the main earth cable - it has a break somewhere, so the starting current is finding an alternative path to earth - the thin earth wire in the loom, that cannot cope and burns out. I see you have already cleaned the earth points back to bare metal, but have you checked the integrity of the earth straps themselves - they can fray over time. Also Paul C's suggestion about sealant between gearbox and engine affecting the earthing - an outside chance but maybe worth checking - you could try using a jumplead to connect the gearbox earth to somewhere on the engine block?
good luck!
Lee

LeeO said

Hi Paul,
all your symptoms sound like a problem with the main earth cable - it has a break somewhere, so the starting current is finding an alternative path to earth - the thin earth wire in the loom, that cannot cope and burns out. I see you have already cleaned the earth points back to bare metal, but have you checked the integrity of the earth straps themselves - they can fray over time. Also Paul C's suggestion about sealant between gearbox and engine affecting the earthing - an outside chance but maybe worth checking - you could try using a jumplead to connect the gearbox earth to somewhere on the engine block?
good luck!
Lee

Thanks Lee
Ok, I think I am making progress

I just called at the garage very quickly on my way home from work.

I checked the earth strap and it is in very good condition with no breaks.

I refitted it and grabbed a jump lead. I put the jump lead on the rocker cover lip and the other end direct to the negative battery terminal.

It turned over; very strong!
It did not start; there are loads of switches/sensors not connected but I will sort all that later.

So this tells us; as we thought that it is an earth fault.

What does it mean though; that the block needs to be earthed??

Many, many thanks

However you're checking the earth strap, clearly it isn't doing it job. If its new-ish looking and in good condition, it can only be the connectors connecting it to the body, gearbox or battery itself.

Do you have a multimeter? Check the resistance between the block and the battery's negative terminal, scratch each with the probe to get past any corrosion. It should read almost 0. Even 1 or 2 ohms here will cause many issues.

I personally think the original wiring on a Mk1 Golf is a little undersized, and its definitely worth an upgrade if it doesn't work properly (if it does work properly, best not fiddling with it!!!)

paul_c said

However you're checking the earth strap, clearly it isn't doing it job. If its new-ish looking and in good condition, it can only be the connectors connecting it to the body, gearbox or battery itself.

Do you have a multimeter? Check the resistance between the block and the battery's negative terminal, scratch each with the probe to get past any corrosion. It should read almost 0. Even 1 or 2 ohms here will cause many issues.

I personally think the original wiring on a Mk1 Golf is a little undersized, and its definitely worth an upgrade if it doesn't work properly (if it does work properly, best not fiddling with it!!!)

Hi Paul
Thanks for this; it is much appreciated.

I do have a multimeter but tbh have only ever used it on volts. I am not going into work tomorrow until the afternoon so will have a look in the morn.

Are we then saying that when I connected the jump lead that the engine itself was acting as the earth?

Cheers

Paul,
glad you are making progress. Sounds like there is poor earthing between the block and gearbox. You could run an extra earth from the gearbox earth to the block. You could test this by using the jumplead but connect it  from the block to the gearbox and try starting it again. Rubjonny recommends replacing the earth straps and starter cable with those from a Mk3 or 4 golf (you need 2 earth straps modded to make 1 new one), as they are much better (certainly the battery post connectors are more meaty).
Lee

Hi
This morning I repaired the wiring loom that was damaged when I removed the burnt earth.

I have plugged everything back in just have a new earth strap to buy and see if that fixes it.

I did try starting it with the jump lead going from the block to the negative terminal on the battery. It turns over but did not start.

I checked that there was fuel to the 5th injector and there was loads. I then removed a spark plug but it appears that there is no spark.

There is 12v getting to the coil.

I am guessing that my earth fault is also causing the lack of a spark maybe?

Cheers

Its a step in the right direction to get it to turn over, even if it didn't start. I'd not worry about getting it to start until you've properly replaced the earth strap - it will be awkward to keep using the jump lead, etc.

There's a number of things it could be to not produce a spark - off the top of my head:

1. ignition switch 30 connection
2. ignition switch 15 connection
3. in and out of fusebox (I don't know the connector numbers because I only have a wiring diagram for pre 1982)
4. coil
5. electronic ignition (I don't have this though..)

If you have an electronic immobiliser then it will interrupt the current between 2 and 3; or 3 and 4. Normally they hack the wires to the ignition switch and use the cheapest, crappiest insulation tape they can find to insulate the connections. They'll probably then try to swing a fully-grown monkey off the wires, then stuff it all back into the dashboard being sure to catch at least 2 wires in the trim; break some of it too; and throw away half the screws used to secure it.