Bad Earth Causing Starting Problems And Overfuel

[dsio]

I've just managed to get my M10 318i to work again after almost 6 months.

What happened was it had badly flooded. To solve it, I pulled the fuel pump relay, and cranked it over heaps while jumpered to a 525i. After about 5 minutes of cranking, it had passed all of the fuel in it, and as soon as I put the fuel pump relay back in, it started first go.

Here is the problem though. After starting a couple of times, it becomes harder and harder to start, overfueling and eventually flooding. Now, I went and removed the power connection to the cold start injector in order to limit this.

Having no cold start injector worked for while, but eventually it UNDERfueled, and just didn't have enough to start. So I re-connected the cold start injector then, and it started immediately.

Heres the problem though. After just a bit of starting, sometimes the starter will stop turning over and just <click> when I turn the key. I have discovered that that problem is an earthing problem. The earth strap from battery carrier to valve cover is rotten and covered in sulphation.

I tried a jumper lead from the negative terminal to the inlet manifold when it was clicking and IT STARTED!

Not only did it start, but the starter motor sounded like it was turning over three times faster than it usually does, after I connected the jumper lead.

Now, is it possible that the earth problem could also be the source of my overfueling? Could it be the thermo-time switch is depending on this bad earth, or that the other temperature sensor is, or that the ignition is being retarded by the bad earth?

I've bought a new big boy earth lead, and I intend to run it directly from the negative battery terminal to the cylinder head.

Any thoughts (Brianmoooore advice would be really apreciated ;))

[Brianmoooore]

A resistive earth strap could cause all sorts of problems. Best thing to do is replace the earth strap, return everything else to normal, and see if your other problems have gone away.

[dsio]

I'm going to replace both earth straps definately. Do you think the negative terminal to valve cover direct would be ok though? It just seams to be the most direct route, and shouldn't be different to going the long way around.

It would be a 3rd earth, to compliment the existing two, rather than a replacement for them.

So the fueling problems and temperature gauge under reading could be caused by this earth problem as well? I'm fairly sure it ran heaps better, started much faster, turned over a hell of a lot faster, and just seamed better all round. Just hoping I didn't imagine it.

If this could solve my fuel problems, it would be a dream come true, and I could start setting up for the 2.2 conversion.

[Brianmoooore]

I would expect a bad earth strap to affect the temp gauge, and possibly cause all the other problems as well.
As for additional straps, I would just replace or repair the originals.
BMW oprobably spent tens of thousands of pounds, or more accurately, marks, deciding exactly where to put those straps