Won't start when hot

[BBRT]

G'day,

My 81 2L GTV turns over but will not start when it is hot. Battery pack or bump start will not help. It will only start when it has been sitting for an hour or so.

Does anybody have any ideas?

[alfagtv152]

Hi BBRT,
A little more information would help us to get an Idea.What sort of ignition system does it have?,what is the fuel pump,does the fuel tank have pressure or vacuum when it won't start.Is the fuel tank getting hot?what is the age of the plugs,leads and associated ignition components?.
I am sure some other guys will join in with relevant questions.
Cheers
Andrew

[Colin Byrne]

I must admit it's usually the other way round, alfa's don't want to start when their cold. 

the next time it won't start  it would be good to pull a plug out and see if it's wet and also check the quality of the spark.

[BBRT]

G'day,

It has electronic ignition from a later 116. The plugs are brand new. Just replaced them because they were oil fouled, thought this might be the problem. Fuel pump is standard.

Cheers

[alfagtv152]

Standard mechanical or electric pump?.I did have a similar experience with a 90 and it was the plugs used,but not likely your problem as you changed them after the problem started.The next thing that comes to mind is heat soak on the fuel pump or ignition module,check that the module is mounted cleanly and securely to the heat sink by removing it and looking under it,be sure to put some paste between it and the base.Have a look at the air gap between the rotor and the sensor,make sure it is small.When it won't start do the basic checks to see if you have spark or not by pulling off a lead and plugging in a spare good plug and watch it while cranking.Remove the air cleaner and push the throttle wide open and look for fuel to squirt out the accelerator pumps.This problem could be as simple as flooding when you turn it off caused by over pressure fuel or faulty needle and seat.The simplest test is to put your foot flat on start up when it is hot.See how you go.
Cheers
Andrew

[MD]

Well, you could say you are lucky in a way. There is no computer involved so your diagnosis is based on three things. Air, fuel & spark. Unless you got a footy sock in the intake manifold, the air part is not a real issue. Old electronic ignitions are a potential problem and if you cannot confirm a good spark, fit the original simple points and coil set up and be sure you use new components including the CORRECT VALUE capacitor. (Coils can go open circuit too). For the purpose of the excercise, remove any radio suppressor capacitor on the ignition circuit in case it gets and internal short when hot.

So then if spark is good and the problem persists, you know you need to concentrate on the one elment left, fuel. It is very unusual to have a vapour lock on an Alfa but I used to own a rear engined Fiat that used to do it all the time. Leave it stand for half an hour after a run and the bugger would never start until it all cooled down- all due to vapour lock.

Contrary to popular belief, swearing aloud and kicking the front tyre is helpful too..   ..but following alfagtv152's suggestions could be more useful