Let's revisit grounding a car

[Lean L]

I heard about car grounding perhaps a month ago. First thoughts that rushed into my head is that it is a pointless exercise since the positive cables are not upgraded. Looking more into it, it seems to be a polarizing subject in that people either swear by it or they say it does nothing sometimes citing empirical evidence.

I took the thought of one forum member somewhere (found via google) to just run a wire temporarily from the throttle body to the battery ground to see if it affects the drive by wire signaling. It costs no more than 5 minutes and a spare small gauge cable, so I went for it.

I did in fact notice an improvement. My car (2009 v6 accord) has always felt like the throttle signal was sent across the country before it reached my engine. There was always a great deal of hesitation. It is actually difficult to accelerate slowly since it felt like it kicked from 0% to 20% and it always caused a lurch. Just that thin cable (maybe 12 gauge) made the car feel more responsive.

I looked into it a bit more and while no one has actually decomposed how the signalling in modern cars actually work, one theory states the following:

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.

- No idea the original source

So basically how I interpret the above is that the signalling to the ECU from the throttle may be combined with the actual TB position that's variably resisted on the negative side. This makes the signalling very logarithmic instead of linear which is what the driver wants.

Anyways, I looked up Amazon and picked up 10 ring terminals and 10' of 4 gauge cable for $17. I figured it was less than half a tank of gas. Might as well try it to verify if what I experienced was a placebo.

I checked the stock battery to chassis ground and it seems to be 4 gauge as well from the factory which is a nice surprise. I sanded down the battery to chassis point then ran three parallel runs to this grounding point on the chassis.

1) TB negative to Engine block negative to battery
2) Alternator negative to battery
3) Transmission negative to battery

This really seemed to kick the car alive. I used to dread the shifting on this car since it seemed to take a full half second for any shift, and the shifting pattern made no sense at all. If I put the foot down to accelerate, the car pondered it for a long time then downshifts roughly and revs the engine. The new shifting feels 'Toyota smooth' and seems to follow what my foot is doing.

The car now seems to fit the 'rev happy' standard that all Hondas fall under. It used to feel just really jumpy.

I can also start my car more easily now. Around this time every year, it seemed my car would struggle to start. This isn't the case anymore.

So this was mostly an anecdote with no real reason why any of these things may be. I cannot say with certainly why the grounding changed the driving characteristics of the car or that there was nothing wrong with my stock grounding or that I am not experiencing an extended placebo. It really doesn't feel like a placebo however.

And to clarify on why the transmission might work better, a direct connection to the battery reduces the resistance that any of the mechanics (solenoids?) would have to endure which might have caused a delay previously. Looking at the stock wiring, the transmission is grounded through the engine block which is grounded by an 8 gauge wire. This wire is responsible for the engine, the transmission, and the alternator. Then the ground has to use probably 10' of chassis to get to the battery negative.

Thoughts?

 

[LevelSea]

It really doesn't feel like a placebo however.

Thoughts?

lol

 

[Gillbot]

lol

X2

 

[olds]

As long as your tires are filled to sidewall pressure, it should be fine.

 

[Ferzerp]

Lol

 

[BUTCH1]

as long as your tires are filled to sidewall pressure, it should be fine.

lol, perfect, lol....

 

[Lean L]

lol, perfect, lol....

I never did get this place at times... How old is that reference exactly? You guys are still hanging on to it for lack of anything better to bond over?

I'm hoping that someone finally tests this theory using voltage measuring and taking into account how the ECU signals one day so this becomes less speculative. I'm perfectly fine being 100% incorrect. This hasn't exactly been a thought provoking exchange so far...

 

[boomerang]

Ditch that throttle body and get one of those 450 mpg carburetors the government suppressed.

http://beforeitsnews.com/alternativ...tors-suppressed-by-us-government-2590184.html

 

[Lean L]

See at least that was original.

We're off to a slow pace it seems. Back on track ATG, prove me right or prove me wrong.

 

[twinrider1]

Have a friend go under the hood and either disconnect the leads, or not, and see if you notice a difference.

 

[BUTCH1]

I never did get this place at times... How old is that reference exactly? You guys are still hanging on to it for lack of anything better to bond over?

I'm hoping that someone finally tests this theory using voltage measuring and taking into account how the ECU signals one day so this becomes less speculative. I'm perfectly fine being 100% incorrect. This hasn't exactly been a thought provoking exchange so far...

We're not trying to be mean, but your stating that a few simple wires all of a sudden made your car run THAT much better is kinda out there. Unless you had a bunch of rusted bad ground connections in which case the wires might indeed make a difference.

 

[skyking]

Unless you use ultra-low oxygen Monster Ground Cables, you are wasting your time.
The dynamic throttle range alone should be reason enough to go with the very best.

 

[LTC8K6]

Disconnecting the battery for a while might have had some effect with the computer reset/relearn.

The only way to tell if it's the grounds is to do a blind test, as suggested earlier.

 

[master_shake_]

Grounding your electronic throttle body with a wire effected the engines performance...

No it didn't.

Absolutely no it did not.

 

[leper84]

So OP you know that there are a metric crap ton of grounds on your car that are directly controlled on/off by modules? As in you're gonna run a new ground wire one day and really screw some stuff up.

Honda spend probably a few million at minimum designing the wiring for your car. You think you can do better randomly hacking up your electronics?

 

[Lean L]

Disconnecting the battery for a while might have had some effect with the computer reset/relearn.

The only way to tell if it's the grounds is to do a blind test, as suggested earlier.

There we go. Now we're talking some logic and some real reasoning. True. I cannot deny that the ECU was reset and may have made a difference that I felt more than any grounding. I'll have to reset the car one day in the future and try to notice a difference again.

So OP you know that there are a metric crap ton of grounds on your car that are directly controlled on/off by modules? As in you're gonna run a new ground wire one day and really screw some stuff up.

Honda spend probably a few million at minimum designing the wiring for your car. You think you can do better randomly hacking up your electronics?

I don't know what yo mean by on off modules but the grounding in the car is simple enough. There's one ground from the engine to the chassis and everything rides off of that for the most part. I'm not hacking into anything and reworking the ground. Simply adding a few points.

Working for a large corporation myself, I can see how easily this ground might be overlooked.

One thing too... The stock battery ground wasn't sanded down so it was conducting through paint instead of directly with the metal. This could also be a reason that I feel things but it highlights exactly that car companies did not have the absolute best in mind for you car. Is it negligible? I have no idea.

Hell this generation of accord has a recall for airbag explosions upon slamming the door really hard, oil burning, and undersized rear brakes.

Grounding your electronic throttle body with a wire effected the engines performance...

No it didn't.

Absolutely no it did not.

I didn't actually say that the engine performed better directly. Rather that things were happening quicker by my perception and the shifting pattern made more sense.

 

[Pacfanweb]

See at least that was original.

We're off to a slow pace it seems. Back on track ATG, prove me right or prove me wrong.

Okay:

You're wrong.

Cars today have grounds out the wazoo.

Unless yours somehow have been tampered with, grounding the throttle body will do NOTHING.

I have never heard of this fad, but then again I only deal with professional shops and mechanics, so that's likely why.

If you have an old Jeep or something...then yeah, they could use some grounding help. But not a modern car.

 

[Pacfanweb]

I didn't actually say that the engine performed better directly. Rather that things were happening quicker by my perception and the shifting pattern made more sense.

That's called the placebo effect. If you were ever wondering what the definition was, or how it might happen in real life, you just experienced it.

 

[Lean L]

Okay:

You're wrong.

Cars today have grounds out the wazoo.

Unless yours somehow have been tampered with, grounding the throttle body will do NOTHING.

I have never heard of this fad, but then again I only deal with professional shops and mechanics, so that's likely why.

If you have an old Jeep or something...then yeah, they could use some grounding help. But not a modern car.

How would you describe these old jeep ground points?

I agree that if I did ground a perfectly grounded car it would do nothing more than cause additional ground loops.

I am not convinced that this car I am working with have grounds out the wazoo. Either that or there was some serious ground corrosion.

 

[HeXen]

If cables and connections are corroded or damaged then sure, upgrading it would seem to bring the car alive in some regards to starting, light lumens or even ground noise through your audio. However low resistance grounds and large gauge copper and direct to frame connections is more relevant for high wattage audio systems where your amp outputs the power it's capable of receiving from your car.

 

[lsd]

There we go. Now we're talking some logic and some real reasoning. True. I cannot deny that the ECU was reset and may have made a difference that I felt more than any grounding. I'll have to reset the car one day in the future and try to notice a difference again.


I don't know what yo mean by on off modules but the grounding in the car is simple enough. There's one ground from the engine to the chassis and everything rides off of that for the most part. I'm not hacking into anything and reworking the ground. Simply adding a few points.

Working for a large corporation myself, I can see how easily this ground might be overlooked.

One thing too... The stock battery ground wasn't sanded down so it was conducting through paint instead of directly with the metal. This could also be a reason that I feel things but it highlights exactly that car companies did not have the absolute best in mind for you car. Is it negligible? I have no idea.

Hell this generation of accord has a recall for airbag explosions upon slamming the door really hard, oil burning, and undersized rear brakes.



I didn't actually say that the engine performed better directly. Rather that things were happening quicker by my perception and the shifting pattern made more sense.

Yes bad grounds can cause problems and can be difficult to find.
But all you have to do is open up the service manual and see the TPS is grounded at the ecu. Why would grounding the TB casing have to do with anything? Obviously nothing, as there is no case ground. The change in performance (if any) is caused by resetting the ecu, that's all.
You need to invest in a multimeter if you're going to do electrical work like that.

 

[Lean L]

Yes bad grounds can cause problems and can be difficult to find.
But all you have to do is open up the service manual and see the TPS is grounded at the ecu. Why would grounding the TB casing have to do with anything? Obviously nothing, as there is no case ground. The change in performance (if any) is caused by resetting the ecu, that's all.
You need to invest in a multimeter if you're going to do electrical work like that.

Thanks, this has some good information that I did not know.

You're saying every TPS for every car is grounded at the ECU? Wire directly to ECU? That would make sense to me.

Now, I'm fairly ignorant at this point, but why do we need a TPS when the throttle is now controlled by the ECU? We can't just assume that the throttle is at where the ECU told it to be? I can definitely see the need in the old pulley system.

What about the quote in the OP, is that wrong or can certain cars be designed as such?

 

[WhoBeDaPlaya]

I didn't actually say that the engine performed better directly. Rather that things were happening quicker by my perception and the shifting pattern made more sense.

This was what my Lincoln LS exhibited when it had a failing/bad transmission solenoid pack / valve body. Performing the reset procedure (disconnecting battery + etc) helped it shift more decisively and smoothly, but after a drive cycle or two, went back to the old defective behavior.

Finally got around to replacing the solenoid body and it is all good now.

 

[lsd]

Thanks, this has some good information that I did not know.

You're saying every TPS for every car is grounded at the ECU? Wire directly to ECU? That would make sense to me.

Now, I'm fairly ignorant at this point, but why do we need a TPS when the throttle is now controlled by the ECU? We can't just assume that the throttle is at where the ECU told it to be? I can definitely see the need in the old pulley system.

What about the quote in the OP, is that wrong or can certain cars be designed as such?

I don't know about all cars but ones I've worked on, yes it's back at the ecu. Just about all the sensor grounds are back there.

I don't know the exact reasons but I'm going to guess we can not control the motors yet solely on the output and in case of wiring problems. A feed back loop is needed for safety & corrections, a measure in case something goes haywire the ecu can shut the throttle if the expected tps value doesn't match the actual.

As far as the quote yes older cars I've worked on had potentiometer based TPS with a 0-5v feedback to the ecu. A bad ground could cause problems, but most problems were in the TPS itself, not external.

 

[SparkyJJO]

Now, I'm fairly ignorant at this point, but why do we need a TPS when the throttle is now controlled by the ECU? We can't just assume that the throttle is at where the ECU told it to be? I can definitely see the need in the old pulley system.

You never assume anything on something so crucial. For something like throttle position you want to have redundancy. Think about it, it assumes it opened to 15% throttle, but because of some fault it actually went to 55% throttle (or heck it pegged it to 100%). That's a bit of a problem. Want another runaway car scenario?

The accelerator pedal in my Trailblazer has dual position sensors that are precisely in sync with each other. I would assume most pedals are that way. If those sensors ever disagree the vehicle will go into "limp" mode and throw a code indicating the fault. At 13 pushing 14 years old and 213k miles I've never had that fail once, but still you want to have that redundancy just in case. Don't need an instance of pushing the pedal 5% to inch forward in traffic and have it rev to 50% and slam me into the car in front of me.