Big hello to all the Cinquecento gurus out there- I'm back with a problem that I'm finding quite challenging (not hard to challenge me)!

My '96 899cc Cinquecento occassionally is reluctant to start, it does one of 2 things; turns over fine but does not fire up or fails to turn over completely/turns slowly (like the battery is flat or weak).
It mainly does this when the engine is warm but it has done it from cold too.

I assume the battery is ok as when it fails to turn and I try again it will turn over fine.
I have given all the earths a very good clean - they are all now shiney and clean. However I could not find where the N/S earth wires go to (there are 3 that go from the earth point on the inner wing, into a loom).
I have also cleaned the starter contacts.

With my limited knowledge I cannot work out what could be causing this. I have read here that the earths can cause problems so that was my first point of action. I have also read that a faulty TDC sensor can prevent the engine from firing on start up - but could this cause the engine not to turn on start up?

Any ideas/suggestions?

It's been a while since I've been on here (the cinquecento has been behaving) and I see you can now donate to the forum. As I'm looking to sell the car soon, when I do, I think it's only fair I pass on some of the money to this forum as it has been ever so helpful and saved me £££ during my 3 years of cinqcento ownership.

The earth you are looking for is on the gearbox.

The single jump lead trick will confirm the problem.

Cheers

SPD

Could you possible tell me where on the gearbox? I've had a good look and searched on here but I still don't know where the earth lead connects to the gearbox I'm looking for a ring teminal right?

I have read about your way of using a jump lead to diagnose a bad earth, trouble is this problem doesn't happen all the time and when it does the car will eventually start - it's not like the car becomes unusable.

Some where in the garage I have a length of thick earth cable (used for an amp years ago) would making an extra earth lead from the gearbox be beneficial?

If you have a jump lead and it wont start try the jump lead to see if it starts.

That tells you the earth is a problem which you need to fix first, before you look for the next fault.

I think the gear box earth goes to the inner wing on the gear box side, you need to wire brush the wing, then sand paper it, sand paper the earth wire termination, coat everything with copper slip grease and replace.

You don't need another earth wire, unless the current one is damaged.

Thanks but I have located the earth point on the inner wing and I have cleaned up both the ring terminals and the 'contact patch' on the wing with emery cloth - they are both sniney, clean and coated in copper grease.
My question is where the earth lead(s) connect to the gearbox? i.e the opposite end to the end that bolts to the inner wing. I cannot find any ring terminals bolted to the gearbox.

The reason I suggested making another earth lead is because I was thinking I could install it and see if the problem goes away - it wouldn't require me to wait until the fault happens and attach a jump lead... I could then then move on with the diagnosis if the fault still occurs.

Should be on one of the bolts for the selector tower.

Another earth will do no harm at all, the more the merrier.

Cheers

SPD

Thanks rallycinq. There is definitely no earth lead coming off of one of the selecter tower bolts - it was the first place I checked as I was sure I had read somewhere else before that the 3rd earth was from there.
Anyhow earth leads are chunky fellas and the wires currently coming from the earth point on the N/S inner wing are only small - maybe from electric componants? They certainly don't compare with the other engine earth leads.

rallycinq said:

Another earth will do no harm at all, the more the merrier.

SPD

Click to expand...

Exactly what I thought, so I've knocked up an extra earth lead out of an old jump lead (couldn't find the big fat amp cable), and used a bell housing bolt to attach it - I guess it doesn't really matter where?
So I'll see how it goes...

Cheers