My engine is dying in the heat - remedies?

[mmatthej1]

On three recent hot days, the engine in my Sprint has just, quite suddenly, after some traffic driving, quit on me - revs drop away and there is no way to save it and keep running. It will not then re-start, just spins over without any hint of firing up. (the engine temperature is fine btw, in lower half of gauge reading and I have anyway been running manually switched cooling fan)

After half an hour, with bonnet up, it restarts perfectly, engine runs just fine.

Has anyone else had such a problem? I'm guessing that it is fuel vapourisation but blowed if I can think of a fix - suggestions please!

[pharriso]

Do you have electronic ignition? The module could be failing...

Fuel vaporization is normally a problem after stopping & heat soaking, not driving.

[JohnP]

Fuel Vapourisation?

Not sure what to do if it is other than make a hole in the bodywork but that would get you disqualified if you were racing at Le Mans these days.

[pharriso]

To see if it's fuel vaporization take a carb top off after it stops...

[RichC]

my money's on it being electronic ignition .....

[billwill]

Or the spark coil expanding and an internal connection coming off.

[nmauduit]

just to rule that out : have you checked the fuse box ? I had that kind of behavior once, it actually was the original fuse box with the contacts not as springy as when they were young (aren't we all?), and the heat increased the phenomenon since the brass would become softer still...

[mbell]

When I had a dodgy power wire to my coil it was easy to diagnose it as electrical as the rev counter would drop to zero. It's not a 100% as failing coil or elec ignition module, coil, rotor, dizzy could cause intermittent loss of spark but if your rev counter drops to zero or significant from engine speed and the engine is still turning due to momentum of the car it is almost certainly an ignition system issue.

[alan.barker]

HT Coil

[XR40]

I had the same problem with an old MGB....turned out to be the coil.

[MarkDa]

My money would be on the coil getting too hot.
Easy enough to change and then have a spare to slip into bracket if the new one suffers the same way.

[Famous Frank]

Replace the coil. Had the same issue with my old 74 Europa. Engine runs fine. After 30 to 45 minutes it starts to misfire and then dies. Would not restart. Let the coil cool and it would run fine.

Frank

[john.p.clegg]

Cheapest/easiest first

1 Condensor
2 Rotor arm
3 Coil

John

[Chancer]

Whenever an engine cuts or misfires your first and immediate reaction should be to look at the rev counter while the revs are falling, if it is indicating the true RPM all the way down without jumping around till the engine stops you can pretty much rule out an ignition problem.

[mmatthej1]

Thanks for all your advice; I've just bought a replacement coil and will give this a try over weekend, then report !