bump starting

[brooky28]

i went to start my car the other morning only to find i had a flat battery. as i live on a hill i rolled out of my drive and bump started it down the hill but have since been told that doing this can damage the catalytic converter. does anyone know if this is true and if so why?

[LostSheep]

According to these guys -
http://www.cats-direct-shop.co.uk/technical-in formation.php -

'4. Never attempt to bump or tow start your car. This causes unburned fuel to be injected into the cat, which makes the monolith overheat and melt.'

[dusty1]

Lost sheep is right, but if it fires up straight away the chances are you have got away with it.

[RATTER15]

Strictly speaking, I understand that you should also not bump start a car fitted with a cam belt as it can cause the belt to jump a tooth and put the timing out, I have done it loads of times though without a problem!!

[Gef]

Have you read the warranty on that link? It seems to say, "If something goes wrong with your cat then it is not our fault".

Surely, repeatedly starting to start the engine also sends unburned fuel into the cat. If not where does the fuel go?

[dusty1]

Gef, you are right but most if not all cars start the first time these days, so the problem won't arise.