Help with an electrical problem please.

[Pills]

Originally Posted by Zedn

I think the Alternator earths through the mounting bracket on the engine (from memory). So as you say David, that earth strap from the block to chassis is probably the culpret. Could just be a bit of corrosion that has formed under the connection.

Zedn, interesting point. From memory, I have not seen an earth strap from the block to the chassis.I will have a good look around tommorow. I could easily make a temporary earth strap to see if this allows the charge circuit to operate corectly.

Cheers Chris.

[Pills]

Can anyone recomend a good auto electrician in the southern suburbs of Sydney. Just in case I cannot resolve this problem over the weekend. I would also be interested to know of any other fellow cobra owners in this area.

I do plan on having Neil Streating do some work on my car during the colder winter months, and I know Sideshow can resolve my electrical issues, but in the meantime someone closer to home and easily accessible would be great.

[Outwest34au]

I'd be grabbing some jumper leads and using them to earth the alternator to the engine block, the block to chassis and the chassis to battery. Quick and easy and you don't have to disturb any connections.
If that shows a positive result then begin with voltage drop checks to find the bad connection.

Also, where is the earth on your fans? Is it earthed straight to the radiator frame? Most radiators are rubber mounted and may not provide a good earth.

[Pills]

Thanks for all your help guys. Problem now sorted out.
Outwest, your advice was spot on. This is the summary of my problem(s), yes more than one fault.
It seems that a poor earth was the START of the series of events to the final outcome.
I had a verry bad motor to frame earth, the alternator bracket was painted, so again another earth failure. This led to a situation where the alternator was working overtime to charge the battery, which led to some of the diodes failing, and the rectifier was also suspect.
We now have the battery earthed to the frame, the starter is also earthed to the frame, and yes the paint removed of the mounting bracket, and the alternator has been repaired, and so far all seems good.

Cheers Chris

[Zedn]

Good to hear you sorted it out. I have found in old cars that 90% of electrical problems are a result of bad earth connections.

Liam

[sideshow]

this is caused by a poor design in the cobra frame
there is no future thought in this problem
nearly every cobra i have done i have sugested to the customer to weld
8 or 10mm studs in afew spots on the frame

one at rear
one under gbox section or near engine mounts
and one up front
then these studs can be used to fit good earth straps to motor and rest of wiring

these should be there from factory but they are not
because most manufactures dont give a rats heheheh

[mickmate]

Glad to hear it's resolved, indeed grounds (earths) are an issue and the jumper cables check is a quick and useful test. Good call Outwest, it's great here isn't it? The studs to the frame is also a good call especially on glass cars. We need a good clean ground connection everywhere critical. This is better than phone diagnostics as you can't get this many people on a conference call.........