Here's a good one.......

[simpo two]

wixer said:

The problem was actually the starter motor. Although it seemed OK when turning the engine over, it was actually old and wearing out and as a result was drawing more current/voltage (forget which) from the cars electrical system and hence weakening the ignition voltage and therefore the spark was weak. This, combined with fuel evaporation, made it a git to start when warm.

Intersting. My 10-year old BMW730 (150K miles) starts fine when cold and when hot, but isn't happy if it's warm, ie been sitting for 1-3 hours. Wonder if your answer could be mine too?

[wixer]

simpo two said:

wixer said: The problem was actually the starter motor. Although it seemed OK when turning the engine over, it was actually old and wearing out and as a result was drawing more current/voltage (forget which) from the cars electrical system and hence weakening the ignition voltage and therefore the spark was weak. This, combined with fuel evaporation, made it a git to start when warm. Intersting. My 10-year old BMW730 (150K miles) starts fine when cold and when hot, but isn't happy if it's warm, ie been sitting for 1-3 hours. Wonder if your answer could be mine too?

It's certainly worth a go, for the sake of a couple of connectors and a few feet of wire. The connection to the coil should be on the positive side, there's generally a redundant terminal you can use.

[the dodger]

rat said:

Might be the ignition module. Black plastic box bolted onto the bracket for the dizzy. That's just as likely to fail when cold though, so I expect the heat-related issues already mentioned are more likely. Hope you've already got it. Andy

Hi. What Andy suggests could the problem. I had a random, intermittent cutting-out problem earlier this year. Sometimes it would fire up instantly, sometimes I would be at the roadside 10-15 mins. This only happened on the journey back from PFest as I put the car away when I eventually got home. I changed everything like you did but wasn't convinced of the cure, and it was difficult to verify. Then I discovered that the contacts at the ign module were badly pitted/corroded. Replaced the terminals on the harness and has been fine since.

Just a thought, and a cheap repair!