Engine Ground Cable
 

What is it grounding exactly? I notice no difference with it in, or out.

You must mean the little ground at the front of the motor. You might not notice a difference right away...but you might eventually, so put it back and ground it well. :)

The reason you probably didn't notice anything right away is because you're grounded at a couple of other points, too, the biggest of which is the gearbox ground to chassis, which you can see from under the car.

the engine is the largest electrical component in your entire car, it needs ample power routing to the battery. Disconnecting one of the grounds may not cause a noticable difference while sitting there, but up the power output of the alternator or run the engine up in RPM and there will be a difference.
IMO it is very wise to keep all grounds in place and in good shape. It will save you headaches in the future.

it is also a good idea to occasionally pull off the grounds and clean all the contact points.

we have seen a few cars here at the dealership where the grounds would vibrate loose, or get a little rust in there, and it would cause all sorts of wierd problems (from hesitation, to radios making whisling noises)

i don't know, but that made me laugh!

My car won't start without that front ground strap.



Clear sign I need to redo the rest of the grounds. :oh: