Is coil failure the answer?

[Thotos]

Precising your answer in late i.e. versions with digiplex ignition there is a crank and a cam sensor.

Ah! I didn't know that   I stand corrected sir....   In fact I didn't know Betas came with digiplex....

[speedyK]

There's no crank sensors on Betas. The problem must be either with the pickup sensor in the distributor or the electronic control unit or, of course, the associated wiring.

Mine is a 1981 Spider with the Bosch electronic control unit and carburettor.

It worked fine when I drive it into my garage. Just refuses to produce a spark now - which indicates a sudden failure of something. Don't think wiring could explain it.

[Thotos]

Mine is a 1981 Spider with the Bosch electronic control unit and carburettor.

It worked fine when I drive it into my garage. Just refuses to produce a spark now - which indicates a sudden failure of something. Don't think wiring could explain it.

I thought so. Same ignition as on my Trevi and my Gamma. When I said wiring, I meant bad connections to the wiring. There's a plug on the control unit and if moisture got in there it could be that the connectors have tarnished and you are not getting good contact. Also the connector from distributor pickup system to the control unit. On my Trevi this wire has bullet connectors halfway (not sure if this is normal or someone replaced part of the wire). It's worth unplugging the connectors on the electronic control module and any to the sensor in the distributor and spraying the connectors with a good contact cleaner (Amberlube by Ambersil is the best http://www.arco.co.uk/products/3450003?gclid=COaSjuHutLsCFakBwwodqGsAHA also available as Servisol Super 10 from Maplin and other outlets http://www.ebay.co.uk/itm/like/231041737721).

I think I may have a spare electronic control unit which I could send you to try if you want.

[speedyK]

When I said wiring, I meant bad connections to the wiring. There's a plug on the control unit and if moisture got in there it could be that the connectors have tarnished and you are not getting good contact. Also the connector from distributor pickup system to the control unit. On my Trevi this wire has bullet connectors halfway (not sure if this is normal or someone replaced part of the wire). It's worth unplugging the connectors on the electronic control module and any to the sensor in the distributor and spraying the connectors with a good contact cleaner

I'll check through all the connectors again, though as it was sat in my dry garage, I can't see that corrosion should suddenly arise and take it from working just fine to not at all...

I think I may have a spare electronic control unit which I could send you to try if you want.

That is most kind 
I may well get back to you on that if I can't find another explanation for the problem. Are these control units the same on all the 2.0 litre Betas?

[Thotos]

Are these control units the same on all the 2.0 litre Betas?

I believe so (except for the Digiplex cars as I was corrected above  ) In fact I think they are the same for all cars that used the same Bosch ignition system. It's the same unit on my Gamma, at least it looks the same 

[thecolonel]

I had 3. Y Reg hpe and they all had slightly different systems.

[speedyK]

Oh dear, that is not very reassuring...

[speedyK]

In the end, I got an "old school" Fiat mechanic to come round and look at it.

I explained again how it had a fully charged new battery, new sparking plugs and a new coil.

He asked me to turn it over - I did and it turned enthusiaistically without the slightest sign of wanting to fire.

He then asked for a screwdriver. I asked what type and he said it didn't really matter.

He pulled a plug lead off one plug and asked me to turn it over again. I did - and it fired almost instantly and started running on 3 cylinders  

He then put the 4th lead back on and it ran as sweet as a nut.

In the cockpit, I hadn't been able to see exactly what he'd done, so I asked.
He gave me a sly look and said "Trade secret!"

Resisting the temptation to punch him, I persevered with my questioning.
He said that sometimes, when a car hasn't started for a while, it "needs a good run to earth" - and from what I'd been able to get out of him, he'd done this by shorting the screwdriver shaft (which was seemingly stuck into the plug lead) against the engine block.

My attempts with a plug lead near the block to check the spark hadn't had a similar result, so maybe he really did just complete the circuit and run it to earth which somehow "cleared" the system. I can't explain it better and he didn't seem to want to, but now it runs fine again.

Make of all this what you will, but I reckon the new plug leads and coil were not even necessary. So if you ever have a similar problem, give this trick a try!

Bloody electrickery - utterly baffling!  

[peteracs]

What an interesting solution. My first guess would be that there was some sort of resistance between the coil and the plug end and shorting 'cleaned' up the connection by allowing a belt of current through. Never heard of that technique and not something I would guess you should do too regularly, but obviously effective in this case....

Peter

[Per]

Hmmm, I never came across electronic ignition behaving that way    Live and learn......