GTV - mystery problem

[poohbah]

Right, this (hopefully) may be an easy one - my 2.0 GTV was serviced and tuned about a fortnight ago, and has been running fine. Right up until I refuelled yesterday. Was still fine on the 5 min trip home, but after sitting for about 30mins, when I went back out, it started coughing, crackling, popping, spluttering, and juddering under load after about a minute on the road. I crawled back home (luckily just around the corner) and left it to look at this morning.

This morning, I started her up, and while a bit lumpy while cold, took her out for a short run round the block. Not perfectly smooth, but almost back to normal (I won't get a chance to run her long enough to get properly warmed up til later today). Main difference now seems to be a bit more blipping on downshift/coasting than usual.

So I am thinking maybe a dirty fuel issue? It certainly felt like a fuel starvation problem, though I guess it could be ignition/electrical related. I note that the points, leads, plugs and condenser were all changed when I had it serviced.

[Craig_m67]

Sounds like it... Perhaps crud in the tank or lines that has shaken free from use and is now in the system.

Change/clean the filters don't forget to clean the fine mesh ones in the carbs and blow out the jets. This happened to my Duetto after the first full tank of fuel that I'd used.

[poohbah]

Cheers Craig, that was my suspicion. I let the tank get reasonably low before refuelling, so it's possible that I may have stirred up 35 years of muck.

[Alfapride]

check your distributor rotor arm or cap hasn't cracked

[poohbah]

Actually all fine now. Choke cable was stuck in the out position (even though it was "in" at the dash). She's been running sweet as a nut since I corrected that.

[poohbah]

Spoke too soon. Have had a recurrence of the problem, and the diagnosis is the distributor is at fault, and screwing up the timing.

It has been suggested that I replace the mechanical points with electronic ignition conversion kit.

Anyone had good/bad experiences with the Hot Spark conversion kit?

[Alfapride]

ive read online that most people use the later Bosch system found in the late alfettas

[poohbah]

Mine does have a Bosch distributor - not sure what the difference might be with later models?

I do like the idea of doing away with mechanical points, given the car is no longer all-original anyway and the kit is not overly expensive.

[Neil Choi]

Similarly, look into Pertronix Ignitor, same I think.

For more $$, 123Ignition electronic distributor with different switchable curves but you will probably only use one or two.  It is programmable I think.

[poohbah]

Thanks Neil. I think the 123 distributor is the ideal solution, but it is also the priciest by far (~$500). Maybe a false economy going for the conversion kit, only time will tell.

I have heard mixed reports about the Pertronix kit, but I imagine it is by and large pretty similar to Hot Spark. Anyway, I've gone ahead and ordered a Hot Spark, will see how it goes once its in.

[GTVeloce]

The later Bosch dizzy was electronic and used a hall-effect sensor rather than points. Both my 83 GTV's came with them.

[poohbah]

Well now I am completely stumped.

I have now had the mechanical points replaced with electronic conversion kit, I have replaced the dizzy cap, rotor arm, HT leads, plugs and ignition coil.

And none of it has made any difference. The car is fine for about 5 mins, but then starts to stutter/misfire and get steadily worse til it is no longer driveable.

Buggered if I know where else to look now - the advice so far has been that it definitely seems electrical.

[Neil Choi]

Check your battery and alternator for good strong electrons?

Can you get another dizzy that you know is working and put it in to try?

Fuel pump inefficiency?

[poohbah]

Battery and alternator seem ok, there is certainly no problem starting the motr, even on really cold mornings after not running for a few days.

Unfortunately I don't have another dizzy on hand to try.

One thing I did notice was that the plug on No4 cyclinder was black, as per carbon fouling. Rest of them all looked relatively good. Workshop manual says carbon fouling (lucky has a picture which matches appearance of No4 plug) can be that mixture is over rich.

Have also seen on alfabb a suggestion that it could be dud wires - and suggests running engine in dim light to see if any sparks from cracks or pinholes. Poor earth connections also suggested. Is getting dark now - will see if I can get illumination.

If I can't crack it this time, I'm just about ready to surrender and get it trucked to the Alfa workshop. I have been avoiding it as I don't like paying +$150 for nothing but a slow ride... (alfa workshop is 30km away)

Also had the fuel pump replaced only a month ago, so I would hope that's not the culprit.

[Neil Choi]

Try a set of new plugs?  BP7ES.  A new set of plugs does wonders.