Car wont start, battery or immboliser

[curtis265]

I have a question. Saw this i my manual once.

It tells me that you clamp the negative lead to a grounding point on the chassis. What difference does this make to connecting the neg. lead to the battery's neg terminal?

[quangsuke]

^ not too sure but it seems to me it jumps starts better.
last time i did negative to negative car wouldn't start.

negative to ground it started.
would love to hear the reason for this though.