It is grounded by default but it seems that its not enough or not fully grounded or its not grounded directly, idk maybe there are other factors made the factory grounding became weak, that's why the additional thick direct grounding wire made a difference

 

Just an FYI I did this on my Ford Ranger. I grounded the engine because the TB is plastic and wouldn't work and low and behold it seemed to make it idle smoother and have more of a crisp throttle response. The only thing other that I did was fill up with Shell gas. Pretty interesting!

 

Put the new ground wire somewhere else on the engine and see if it has the same effect. If so, maybe the engine benefits from the extra ground and not the TB itself. That's my point -- there's nothing magical about the throttle body in this equation.

 

I just got in and read your post, tried the wire on a couple of other points beside the throttle body bolt. Nowhere else steadied the idle at all. Stuck it back on the throttle body and cranked the truck again, dead steady idle...

 

So you had good resoults with the ground by putting it just to the motor your saying? Where on the engine did you bolt it?

 

Tell you what, I was skeptical as hell when this thread started up...but I tried it because it's both cheap and very easy. I will second that my idle is definitively improved after grounding the TB. I may even record video of it.

 

I haven't done it yet. I'm the official nay-sayer

It's the nature of my business. I troubleshoot for a living. I have to see a cause and effect. If something works, I want to know how and why.

There is no electrical reason in the world that a ground wire (and one that has to be large according to reports) connected to the throttle body would improve anything, or that connecting said wire anywhere else near the TB wouldn't have the exact same effect. We're talking solid aluminum here so a few inches away from the TB should give identical results. Why would a 16 gauge wire (capable of 50 amps current @ 3 ft length) not be enough but a 4 gauge (capable of over 400 amps of current @ 3ft length) provides results? Just how much current are we flowing through this throttle body?!

Plenty of people have said they see positive results. That's fine, but it still doesn't explain how or why that's the case, and where the shortcoming is in the stock setup.

 

It makes no sense, but I cant speak any on this mod as it does not work on highly modified vehicles, which also doesnt make much sense because if it adjusts the sensitivity and response it should do it across the board modified or not. A gain is a gain.

 

Jeez now I have to try it

 

I do not have a way of testing how much is going through but I am sure there has to be a way of seeing actual numbers to back up the differences we are all seeing here. I might go out and get a bigger wire just to see if I get any changes. I would guess one could put a meter inside the ground wire halfway between the TB and the ground in a smaller wire and then again in a thicker wire and get some starting point for numbers and measurements, but my question would be when is a thicker wire so thick that it doesn't make a difference? Like what if someone used a 3/0 wire, is that just too big to even try?