dieseldriver
Member
Throttle Boby Grounding Mod
I accidentally stumbled upon an article about grounding the throttle body on a Mazda3 engine for better throttle response since it's a drive-by-wire system. All it is a grounding from one of the throttle body bolt to the body. So found a 8 gauge grounding wire from one of my amp wiring kit, and bought 2x copper 6gauge crimp on connectors for $1.30 at local True Value Hardware. I removed one of the screws from the throttle body and ran the cable to the existing grounding point on the driver's side of the fender flange.
Went for a test spin and I could not believe the engine response after this mod. The lag for kick-down when throttle is depressed halfway is cut down by more than 2/3 and the acceleration has greatly improved as well as it wants to run smoother -- almost feels like the engine is now reving much more freely. First I thought maybe it was some sort of a placebo effect but it definitely wasn't as from 5th on a steep hill, it would take 2-3 seconds to kick down to 4th for more power but now it kicks down with less than 1 to .5 seconds to do that. I'm not sure if the grounding point actually is causing a greater potential / voltage difference for the ECU software to detect a change in condition to act upon... not sure. It would be nice if I can compare with software that was available to VW's like a VAG-COM with realtime diagnostics on the Mazda as well.
EDIT:
I think I may have the explanation for the grounding that makes the engine feels more responsive. Throttle, or the "pedal" is basically a potentiometer that's connected to a voltage source that varies the input voltage on the input of one of the pin(s) on the ECU. It may be that the actual mechanism that controls the air/fuel mixture is sharing the same grounding point that's limited at which case, may be introducing a sort of parasitic reistance of its own. Now, as the resistance on the pedal/potentiometer varies, input voltage will vary accordingly. However, because there's a finite amount of resistance on the grounding wire side, it may be introducing a variable voltage drop of its own. Now, think about it, when it does that, ECU with lower than expected voltage at any given time which may explain why further travel or higher resistance is needed to get the result one was expecting, i.e. I've noticed this on a hill when I needed more HP but the gear would not kick down until I press it almost to the floor, then the engine sounds like it reving out of control, and at times, too much rev and torque results giving the driver less control.
Adding a less resistant ground of the throttle body may just be the trick into getting rid of that parasitic resistance at which case, now the ECU may be sensing a better input voltage.
Here's some more update. On the way to work, noticed that the throttle pedal feel is much more progressive, meaning, there's no more of that DeadZone feel where the engine just sits there trying to decide what to do. Instead, as you depress the pedal it revs the engine by that much. You can really feel the difference when the car's starting out from 0MPH like on a red light or stop sign. I am now convinced that it was a grounding issue that may been causing some of that electrical back pressure (analogy to hydro dynamics). Without that back pressure, now the voltage gets to the ECU with very little resistance and it signals to the throttle body to do just that. I have to say though, car feels totally different but really smooth, and it almost feels like this is how it was meant to perform not like previously. I will let it run like this for some time and report back with the long term experience with this mod but so far from what I've seen, I am happy with this mod.
Please feel free to jump in and add your comment!
I accidentally stumbled upon an article about grounding the throttle body on a Mazda3 engine for better throttle response since it's a drive-by-wire system. All it is a grounding from one of the throttle body bolt to the body. So found a 8 gauge grounding wire from one of my amp wiring kit, and bought 2x copper 6gauge crimp on connectors for $1.30 at local True Value Hardware. I removed one of the screws from the throttle body and ran the cable to the existing grounding point on the driver's side of the fender flange.
Went for a test spin and I could not believe the engine response after this mod. The lag for kick-down when throttle is depressed halfway is cut down by more than 2/3 and the acceleration has greatly improved as well as it wants to run smoother -- almost feels like the engine is now reving much more freely. First I thought maybe it was some sort of a placebo effect but it definitely wasn't as from 5th on a steep hill, it would take 2-3 seconds to kick down to 4th for more power but now it kicks down with less than 1 to .5 seconds to do that. I'm not sure if the grounding point actually is causing a greater potential / voltage difference for the ECU software to detect a change in condition to act upon... not sure. It would be nice if I can compare with software that was available to VW's like a VAG-COM with realtime diagnostics on the Mazda as well.
EDIT:
I think I may have the explanation for the grounding that makes the engine feels more responsive. Throttle, or the "pedal" is basically a potentiometer that's connected to a voltage source that varies the input voltage on the input of one of the pin(s) on the ECU. It may be that the actual mechanism that controls the air/fuel mixture is sharing the same grounding point that's limited at which case, may be introducing a sort of parasitic reistance of its own. Now, as the resistance on the pedal/potentiometer varies, input voltage will vary accordingly. However, because there's a finite amount of resistance on the grounding wire side, it may be introducing a variable voltage drop of its own. Now, think about it, when it does that, ECU with lower than expected voltage at any given time which may explain why further travel or higher resistance is needed to get the result one was expecting, i.e. I've noticed this on a hill when I needed more HP but the gear would not kick down until I press it almost to the floor, then the engine sounds like it reving out of control, and at times, too much rev and torque results giving the driver less control.
Adding a less resistant ground of the throttle body may just be the trick into getting rid of that parasitic resistance at which case, now the ECU may be sensing a better input voltage.
Here's some more update. On the way to work, noticed that the throttle pedal feel is much more progressive, meaning, there's no more of that DeadZone feel where the engine just sits there trying to decide what to do. Instead, as you depress the pedal it revs the engine by that much. You can really feel the difference when the car's starting out from 0MPH like on a red light or stop sign. I am now convinced that it was a grounding issue that may been causing some of that electrical back pressure (analogy to hydro dynamics). Without that back pressure, now the voltage gets to the ECU with very little resistance and it signals to the throttle body to do just that. I have to say though, car feels totally different but really smooth, and it almost feels like this is how it was meant to perform not like previously. I will let it run like this for some time and report back with the long term experience with this mod but so far from what I've seen, I am happy with this mod.
Please feel free to jump in and add your comment!
Last edited:
