Earth wire on engine block....

[Tobs]

I’ve recently been having a few probs with the engine on my chim. Generally rough running and only getting 13-14mpg out if her (see my other threads through my profile!). Found the vac line to the fuel pressure regulator wasn't connected yesterday - and that seemed to make things better, but still a slight misfired/ rough running on the way back from work.

Just been looking under the bonnet in the dark to see if I could see any sparks from the HT leads, as I suspect these maybe breaking down, and while doing this noticed a redish glow/sparks from some earth connections to the block at the back of the engine on the nearside. It look as though the nut on the stud has come off and the ring terminal on the end of the wires is just over the stud making an intermittent contact.

Does anyone know what these earth points are for i.e. are the important to engine running? I'm obviously going to clean up the connection and put a new nut on etc. but I was interested if anyone else has had a similar problem?

I've also just bought some new ignition leads/dizzy cap/ coil etc to try - maybe I won’t need these now! Although I think I’ll still fit them.


Cheers,

Toby

[Tobs]

Thanks for that. Yes sounds as if this could be something to do with the rough running - I havn't had chance to re-attach the earth yet but hopefully this should improve things!

[GreenV8S]

You should find a pair of wires which earth the ECU to the engine. On mine these are clamped under the fuel rail securing bolts, but they might be connected elsewhere on yours. With a poor earth the whole ECU is liable to go bonkers (mine would intermittantly cut out, start but not keep running, produce variable power and generally be very unhappy).

The fact that the engine cranks over OK proves that the main engine earth is OK.