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Hi

Anyone know where the earth points to the chassis are?

I have an electrical gremlin... The voltage is dropping a lot when I put load on - sometimes it's down to 10v although it slowly picks back up. I was ready to fit another alternator tomorrow as I thought it was failing, but not so sure. Today it just clicked on the starter, voltage dropping to 8v when the key turned. Thought the battery was dead. Suddenly it spiked up to 12v and fired immediately, showing over 13v running.

Only time I've seen similar was on my RS2 which turned out to be a corroded earth point... Hoping to check it over and see if it's a simple fix, but not sure where to start.

Cheers
Ross

Try making a temporary earth with some jumper cables between the battery negative terminal and the chassis with one, and the engine to the chassis with another and see if that makes any difference.

If memory serves me right wasn't there a similar topic a few months back on a C5 which I'm sure turned out to be corroded power terminals under the bonnet area up near the bulkhead?

Here you go. I think this is the one

http://forum.rs246.com/viewtopic.php?f= ... lt#p568648

Lol, helps when you actually make it a working link

http://forum.rs246.com/viewtopic.php?f=2&t=101452

Here too - http://forum.rs246.com/viewtopic.php?f= ... 92#p548879

I was in the process of correcting that as you posted. Lol

There is also a local earth for the alternater onto the chassis it is tucked up behind it

Spot on fella's

My missus had complained of a funny smell in the car a couple of times, I found the coolant cap a turn loose and it was down about 1" so I suspect it was not holding pressure and loosing some out of the cap. That was last week. Pulled the header tank out and that junction box underneath was cable tied in place and corroded to hell - not as bad as the pic in your link but still bad! And the coolant overflow pipe was right above it (the box was not attached to the bulkhead) so probably my theory was correct and that finished it off.

I cleaned up the terminals, and connections with sandpaper and carb cleaner - same also with the nuts n bolts - put it back together all cleaned up. I found some bolts to attach it in the proper position and added a bit of hose to the overflow on the header tank and routed it to a drain hole. So a bit of design improvement right there. Cleaned up the battery terminals too.

The voltage is sitting on about 13.8-14v regardless of load now, starts nicely, and it's not thrown up a code for SAI either which it usually does. I just covered 150 miles without issues, sure it felt better/smoother than it has in a while, even the gearbox behaved with kick-down and 1st/2nd WOT not causing any slip or hard changes, but I'm sure it won't last long

Glad to help and glad you got it sorted. Definitely big hats off to footers for finding the correct thread

Nothing quite as satisfying as fixing something yourself aswell

In terms of feeling like it is running smoother it could be down to everything is now getting a regular voltage instead due to nice clean solid contacts.