1995 fuel level sender wiring

[TomB]

Wiring query, fuel level sender on a 1995 K series: there are two earths on one of the fuel sender connections. They both go to a common earth on one of the left  rear wing bolts. Why can’t this be one wire? Does it carry a high load?

Any thoughts? 

[Jonathan Kay]

Is that bolt used to earth anything else such as the lights?

Jonathan

[TomB]

The ring connectors shown are for the terminals on the sender, on top of the tank. The other end of the earth cable has another ring terminal that earths to the skin using one of the wing mounting bolts. The lights have their own earth in the plug for the lights.

 

 

 

 

 

 

 

 

 

 

 

 

[TomB]

Further, on the wiring diagram, does E1 and E2 refer to separate earth points, or just two wires going to the same one? On my butchered loom, the two wires from the sender combine about half way to the earth point. 

Could twin earths be a safety feature to ensure that the tank is well earthed? Perhaps for more capacity or redundancy?

[Jonathan Kay]

OK. Back to basics.

Can you add a photo of the whole cable? And the sender?

Does the tank have another earth?

Is anything else connected to that bolt to the skin?

What year, model and engine is the car? And that diagram?

Jonathan

 

[TomB]

I can't do a photo at the moment, as Im at work. However:

1) no, the tank is earthed only from the sender on top of the tank to the side skin.

2) The earth is attached to a wing bolt, as is normal.  There is another ring connector on this point to which I've earthed the high level brake light through.

3) 1995 Dedion, K series.  This diagram is that in the handbook for my car, labeled 'Circuit diagram: Caterham Seven main vehicle harness for injected engines.  Item 15 is the fuel level sender.  

My current ( ) thoughts are to replace with a two thinwall earth cables from the sender to the body earth. I expect the tank must need a good earth to mitigate any static build up, and Im replacing the 23 year old wiring at the back to take out multiple joins and bodging over the years.  The existing earth is already extended, and possibly incorrectly joined.  The diagram says to runs to earth, so that what Ill put in.     

 

[Jonathan Kay]

From the same diagram, top left:

Jonathan

[bjw]

Firstly, no, there's no need for two earths to the fuel sender. The two wires before 'butchering' were originally simply a 'via' between two other earth points.

The E1 and E2 symbols are labels showing the routing to another part of the diagram, not earth connections themselves.

For comparison, on a 1999 Classic, the frankly bizarre earthing arrangement is as follows:-

1. Starting at a chassis connection in the engine compartment a long wire goes to a soldered and crimped junction in the loom near the rear end of the tunnel.
2. From that junction the earth connections are 'starred' out to the right hand light cluster, the fog lamp, the reverse lamp*, and the fuel sender. (*By 1999 the reverse lamp switch is no longer a short to ground type.)
3. A second wire from the fuel sender earth then goes to the left light cluster...

There's no separate earth for the tank itself - the sender ground is sufficient.

>>The earth is attached to a wing bolt, as is normal.<<

I'm quite surprised Caterham would ever have used a wing fixing as an earth ?

Cheers