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Thread: Drive by wire and throttle respoonse

  1. #1
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    Drive by wire and throttle respoonse

    I would like to know if the devs over at HPT have thought about adding a feature to adjust the accelerator pedal input smoothing?.. I am pretty sure that there is a buffer of some sort that holds a specified number of readings taken from the accelerator position sensor and it averages that buffer and that is what gets used to set the throttle.

    Having a way of adjusting the size of that buffer would be a really nice feature to have especially on vehicles that have drive by wire when it was still a newish technology. The ECM's were really not up to snuff in terms of speed and the buffers were to large so you ended up with throttle response problems. Attaching a device to the accelerator position sensor that offsets the value is not the proper way to go about doing it, and those things don't do a thing when you mash the pedal to the floor.


    I do not know how large the buffer is, what I do know is that my 2008 Pontiac Solstice takes quite a long time for the throttle to reach 96% when I mash the accelerator to the floor. I am not taking 2 second, closer to 5 or 6 seconds if not more. I would have to go back and check.

    As an example, If you have a buffer of say 40 values and all of the values are at 30 the average is going to be 30. then you add a value of 90 to that buffer. the averaged amount is going to be 31.5 it is gong to take 39 more readings of 90 before the average is a 90. That is going to cause a lag in the throttle. This is done to help improve gas mileage because it smooths out fluctuations caused by a persons foot. I don't think the people using HP Tuners care to much about fuel efficiency.

    I know that I would rather have as close to real time throttle response over MPG.

    You can thank the EPA for this wonderful gift...

    I would think that there has to be a way to adjust the size of the buffer or even eliminate it completely..

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    Since you didn't attach your tune file I grabbed some random Solstice file from the repository to get an idea of what you have available to work with.

    E69(?) seems to be very limited. V8 files have all kinds of stuff for Electronic Throttle.

    However it would be great if you could upload a file so somebody could see what changes you've made (and if they helped or did nothing) at Engine > Torque Management > General > Tip-in Limiting.

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    OK I attached the tune file, a log for that tune and also the scanner layout and channels files.

    The 5-6 second throttle response issues are when I let off the accelerator, The ECM actually continues to open the throttle body further for upwards of 1-1.5 seconds after I have let go of the accelerator. and it takes another 4-5 seconds after that before the throttle closes.

    On acceleration from peak of the accelerator pedal position to peak of the throttle position is it typically 1 - 1.5 seconds delay between the 2.
    Attached Files Attached Files

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    Does it do that for real, or are you inferring that it's doing that based on the timing of things you see happening in the logs? Because I have a hard time believing that it wouldn't be a massive scandal/recall/breaking news if that was the intended behavior and GM allowed it to leave the factory like that. Logs can be misleading, some channels update faster than others and it can look like things happen out of order when they really don't.

    I see a whole bunch of stuff changed in that tune, and not a lot of actual tuning. I can't make sense of the reasoning behind most of the changes. I would first return the tune to stock (or as stock as possible, allowing for any hardware changes) and see if it starts behaving normally.

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    I can't go back to the stock tune because of changes that have been made to the engine performance wise. The car would not run properly.

    There has always been a throttle response problem with these cars and also with the 2.4 N/A version of the car. It is a very noticeable problem while driving the vehicle. I do not understand as to why there would be logging delays as the information for the throttle position, accelerator position, vehicle speed, and RPM should be broadcast on the high speed can bus, there shouldn't be a need to send a request to the BCM on the low speed bus and then have the BCM reply.... I would hope that the HP tuners scanner is not using OBDII requests to collect this time sensitive information that a user is supposed to use to tune a vehicle. That would completely blow my mind if that is what is being done and it would make dialing in a tune hard to do I would imagine.

    I personally do not feel that I have enough knowledge to be able to safely tune a vehicle, There is a place that is doing the tune remotely, they specialize in these cars and have been doing the tunes for years. That being said, no person tuning a vehicle knows everything about tuning, they are always learning new tricks or how to adjust something. So having more eyes take a look at it there could be something that is getting missed or not being done...

    Also if it was a "delay" in the logging then the delay would be a constant, it would be the same across the entire log. the offset from the delay would be easily seen. This is not the case. the throttle delay seems to change with how much the accelerator position is changing from previous readings. If the change is large the delay seems to be less, if the change is small it seems to take longer for the change to be realized in the throttle position. This type of a phenomenon would be caused by a smoothing algorithm in the ECM, which is the reason why I asked if there is a way to alter this portion of the ECM to be able to give the driver a closer to real time throttle response.

    On my car the turbo has been changed on the vehicle, it is a significantly larger turbo then what the stock one was. The new setup now uses an external waste gate instead of an internal one. the original turbo has a 100% recirculating valve, there is now 50/50 valve that vents some of the pressure to atmosphere and recirculates the rest of it, the IC has been changed and has some 250% more cooling capacity over the stock one. map sensor has been replaced as well as the charge pipe pressure sensor to one that has a higher upper limit, charge pipes have been replaced and also the intake. The cat has been replaced with a high flow. There are also a lot of other changes made but nothing that would need to be accounted for in the tune.

    Most vehicles that were made with drive by wire during that era have throttle response problems. It is not a new thing. This was corrected in later releases of the cars by changing the ECM. The Solstice was not made long enough to have that happen. I used to own a 2005 Lotus Elise. I specifically bought the 2005 MY because the 2006 MY has throttle response problems because this was the first year they had drive by wire in the car. the 05's were mechanical.

    I know that these ECM's work on a torque demand system, they learn away any performance upgrades unless the ECM gets tuned. There are things programmed into it that intentionally reduce output power, the differential in the Solstice is not up to the task of handling the output power from the engine when "launching" the car. The ECM reduces the output power of the engine. I believe it does this until the last half of second gear, it is done so the diff has less of a chance if failing. From what information I am able to locate in the internet about these ECM's there are some 2500 tables in these things where most other ECM's have what??? 250 tables or there about.. There is a very small amount of things that can be altered via HP tuners. There are other companies that offer tunes and have access to more then what HP Tuners provides but they are "canned" tunes and not a DIY type of solution. I live at 8500 foot altitude, I need a custom tune done to get the most possible out of the setup I have.

    after 12 years of this ECU being around (and they are used in several GM vehicles) I would have thought by now there would be more available form HP Tuners. It is not a matter of having to reverse engineer them anymore, that work has already been done the knowledge is there. it needs to be added to HP tuners to allow access to them. You had stated that there are more parameters available for the V8's for adjusting throttle controls. why is that? I am willing to bet there are far more Chevy Cobalts (use the same ECU as the Solstice) that have been sold then say a corvette of the same era.. Same thing goes for the 2009-2011 Chevy Camaro with the V6 in them. once again same ECU. Cadillac CTS is another. These cars are outside of their warranty and people are more then willing to spend the money to tune them. they are also cheap to buy so there is more money available to upgrade them. This is what is taking place with the Solstice. they are cheap and the people buying them are the 40 and older crowd and have the money to put into them. HP Tuners is not used as often as it should, the reason being is the limited access. at least twice a week there is someone new on the forum and they just bought a Solstice or a Sky and are asking about tuning the car, or the throttle response. HP tuners is not mentioned. It should be the go to tuning solution especially after 12 years since the release of the car. I know that HP tuners has lost popularity over the years, most likely due to the fact that they offer access to only some functions and then they call it done and do not continue to add more. They get enough so they can add a vehicle to their compatibility chart and then development for that platform/ECU becomes stagnant.

    I would switch out the ECM for something different if there was anything that would work that was OBDII compliant. I have not been able to locate anything that would work.

    The "canned" tune options get locked. so If I wanted to get the car on a Dyno and have a shop make some adjustments to the tune it cannot be done. This is a deal breaker for me. The other thing is the whole "tool rental", I would not have the ability to flash a tune that is made for sea level and then a different one for high altitude. Only the manufacturer of the canned tune is able to do it, another deal breaker.


    As far as the "scandal/recall" thing is concerned. Never gonna happen. The Solstice uses the exact same HVAC system that the Hummer H3 uses, the H3's have been recalled for a meltdown of the wiring harness to the blower motors. This same thing is happening to the Solstice/Sky, these cars were not included in the recall and we have been fighting to get it included with no luck. The recall for the passenger presence sensor for the airbag, the fix... a piece of duct tape, and guess what that works for 2 years but since the recall has been performed on the car the owner of the car how has to foot the 1000.00 bill for replacing the sensor. This is what should have been done in the first place. Unless someone gets injured or dies it's not going to get fixed. and also because of how GM trolls through the internet looking for people that post information about their systems and if they find someone they send them a cease and desist letter for copyright or trade infringement, no one is going to be able to provide the NHTSA with concrete data about the problem. There was a group of people that hacked OnStar they could control every aspect of the car except for steering (the ability didn't exist at the time), this group privately told GM about it instead of going public and causing all kinds of issues for GM. GM's response.. The information about it got buried and there was probably a gag order put in place on the individuals that found the problem and then GM took their sweet time fixing it, 10 years.

  6. #6
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    Jesus. Have you ever owned a Fiero? (anyone who has known Fiero owners will know what I'm getting at here)

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    Jeep Grand CHerokees continue accelerating 1-2 full seconds after you let off the throttle. It's just delay, and annoying. Not a scandal, LOL

    Regarding the "buffer", on 2010 Camaro E38, there is a table called "Opening Rate". High numbers make it respond instantly, lower numbers make it respond slower, I actually prefer a bit slower for the opening rate, but this does not affect the closing rate.

    You may want to ask if they have a "closing rate" table. There may be one, if HPT can find it, or wants to find it, that is the question.

    Logging delays come from the HPT scanner methods not being optimized to the ECU, is all, nothing else. Like my 2020 Silverado, not optimized, things like RPM update very slow. Same with the tune file not showing as many available parameters as others, HPT just hasn't spent the same amount of time on them.

    Regarding your throttle opening/closing rate, that data looks choppy, if you zoom in, it looks like stairs, where it moves a bit, then stops, moves more, then stops, etc. The logging rate in the raw data looks good, but the value is stepped like that, hard to say if the blade is acting that way.

    Also noticed you have some settings for ETC Load Damping, you may want to adjust those for now. One in particular, is ECM 33040, says set to maximum to disable, your values are as low as 10%. In my opinion, you do want some ETC smoothing, or delay, at least with Whipple superchargers, as I was getting some pretty severe boost spikes wtih stock rates, set very fast.

    as Blindsquirrel says, you can change one thing seemingly not realted to TPS, but the TPS can start acting strange, and that could be due to the torque management or this Load Damping stuff. I reduced the rate of my TPS blade just a bit, and now between shifts at high RPM, I get full on delay before the TPS blade starts to open sometimes, and sometimes not. Obviously not related to Opening Rate, but this did not happen with stock full speed opening rate, and it is not consistent, but still not a big problem, it actually helps me not abuse my clutch and driveline as much, so not worried about it.
    Last edited by 10_SS; 1 Week Ago at 09:17 AM.
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    Quote Originally Posted by blindsquirrel View Post
    Jesus. Have you ever owned a Fiero? (anyone who has known Fiero owners will know what I'm getting at here)
    Hahahahaha. I get it. It was real. I have personally experienced 4 separate instances. Fun stuff.

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    Thank you @10_SS, I didn't think I was imagining it, I was starting to worry there for a minute. It drive me crazy having to wait 1-2 seconds before the car responds to what I am doing with the pedal.

    I Thought that the stepping may be what the scanner software does to fill in data gaps.. if the car responds to the accelerator position faster then it does for the throttle position there could end up being gaps in the data for the throttle position so what the software does in those cases is it fills the gap with the previous reading. This would cause a flat spot in the graph.

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    Here is a video that shows the throttle response, This video is for a 2.4 N/A and not my vehicle. This gives you an idea of how slow it is. In this video the accelerator is being mashed to the floor


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    Quote Originally Posted by blindsquirrel View Post
    and see if it starts behaving normally.
    The throttle response is how it normally behaves. This is nothing new. It was there with the stock flash and it is there now. Nothing has changed.

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    That's a long data file lol. But I browsed through it and don't really see anything out of the ordinary. You're right that the response is filtered...but it's not a simple buffer, or moving average. It is a huge piece of software in the controller that performs interactive shaping of the torque produced by the powertrain. It's sort of the fault of the EPA...technically slower torque transitions yield better emissions. But a big part is keeping the response smooth for the millions of people who drive vehicles and don't care how fast it responds. Another big reason is smooth management of lash cross as you transition from accel to decel and vice versa. More gears in modern transmissions means more lash to negotiate...it has to be smooth and subtle. Both for driveability and health of the transmission.

    I can't speak to the exact reasons for HPT's omission of most torque shaping calibrations, but I would bet that those memory segments are not easily defined. Torque security is a huge concern for manufacturers, and by proxy, HPT as well...I doubt they'd be interested in lawsuits due to accidental death due to a throttle that hung WOT because of a customer that fat-fingered a value in the cal. Everyone in the industry remembers the Toyota floor mat issues causing cars to 'get stuck wide-open'...and it wasn't directly the fault of the manufacturers. These are my thoughts anyway...

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    The problem with the Toyota vehicles was driver ignorance. This driver ignorance did uncover a flaw in the design of the Toyota's. The brakes were made to small to stop the vehicle in the event something like that happened. or even if the electric motor went offline. A large chunk of the braking ability on those vehicles came from using the electric motor as drag, this also charged the battery. If that system stopped working and the motor didn't put that drag on the vehicle then the mechanical brakes should be capable of stopping the car. This all became apparent because of the inability to take the vehicle out of gear when it was in motion. It was designed that way because Toyota knew if the electric motor was not "attached" to the wheels that the car would be unable to stop properly. They thought there was no need to provide the ability to detach the electric motor from the drive wheels. Well guess what?? they thought wrong.

    Just about every person that has driven a vehicle before they started putting hooks on the drivers floor mat has experienced the mat bunching up under either the brake pedal or even under the accelerator. It is not a new thing for that to happen. Toyota didn't take that into consideration.

    Why do gasoline vehicles have the ability to shift into neutral at any point during the vehicles operation??

    So we can blame the drivers that had the floor mats bunch up.. or we can blame the right people for the problem which is Toyota. It is not just a problem with the floor mats.. what if the driver has a heart attack and passes out or dies and their foot mashes down on the pedal.. any passenger in the vehicle should be able to take the car out of gear and coast the vehicle down to a stop. Toyota's design has just put all of the passengers in a casket. They were too blinded by $$$ because of the saving money that didn't get spend on engineering a neutral gear that could be shifted into and out of while the vehicle was in motion. The money they saved by making the braking system 1/2 the size it should have been designed. This saved them a lot of money and they didn't think about anything other then their wallets.

    Oh and I also do not believe that the vehicle can be turned off while it is in motion either.. Kinda strange that you can do that with a gasoline engine.. Most of this kind of information get swept under the rug. and the blame passed onto the driver. What do you think Toyota would look like as a company now had they been held accountable for all of these design "flaws".. Defiantly not the Toyota you see today.. Every single EV they made they would have had to buy back and scrap. I do not think that there would be too many people wanting to take the pitiful amount of money they wold get on the buyback (because you know the consumer is the one that would get it right in the poop shoot on that deal) and buy another Toyota with it.

    I am still waiting for one of these EV's to start having their batteries explode. kinda like the Samsung cell phones did. That will be the end of EV's for a while..

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    II am not sure what or how the throttle is controlled on these ECM's. It appears to me to be a smoothing algorithm to remove small fluctuations in the drivers foot. It has been known for as long as I have been alive that when operating an "old school" manual type accelerator that a steady foot yields better fuel economy. There was no push to develop drive by wire systems in cars until the EPA set those deadlines for fuel efficiency. drive by wire was nothing new and had been around for 2 or 3 decades it was called "fly by wire" and was used in planes.

    Still to this day vehicle manufacturers have not invested any great amount of effort into making the engine more fuel efficient. they have made the vehicles lighter. put in electronics that remove the human factor that can cause lower fuel economy. And now you are seeing most manufacturers with vehicles that have some form of forced induction so they can use the really small 120HP engine to meet the EPA targets. Oh and let me not forget the vehicles that shut off the engine when you stop at a traffic light. They have not had any kind of a large improvement to the fuel economy of the engine. they have done everything to skirt around having to do that. the modern engine only uses 20-30% of the energy that is in gasoline. ummm... why? I have a water heater and 3 furnaces in my house that use natural gas, also a fossil fuel. they use 97% of the energy. they capture so much of the energy that the 3% that is exhausted in the form of heat exits my house in a plastic pipe. The exhaust iis about 1/2 the temperature of a hair dryer.

    so if we captured 60% of the energy of gasoline now the cars that get 35MPG would get 70 MPG. The methane from a cow when it farts pollute the air more then a SULEV vehicle does. I remember when it was a big deal about a vehicles "emissions" this a all of the crap that comes out of the tail pipe. Because almost alll of the crap is filtered out and what is coming out of the tail end is water/water vapor and CO2 the concern is no longer about emissions. It is about CO2. Lord knows we have enough people that are all kind of up in arms about cutting down trees. Give those folks a shovel and tell them to start planting more. Trees turn CO2 into O2. There is also the ability to split CO2 into carbon and oxygen. the oxygen can be reused in the engine over and over again and the carbon can be captured and recycled. once gasoline vehicles have become the minority the eco-wackos will shift their attention to the very thing they pushed to get used and there will all of a sudden be all kinds of problems with that and how it's damaging the environment. There is nothing that can ever be done to make those people happy.

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    The other interesting part is that throttle opens slow, but consistent. Your datalog shows stepped throttle opening, notchy, like steps. Due to slow PID update rate.
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    Quote Originally Posted by smokeshow View Post
    That's a long data file lol. But I browsed through it and don't really see anything out of the ordinary. You're right that the response is filtered...but it's not a simple buffer, or moving average. It is a huge piece of software in the controller that performs interactive shaping of the torque produced by the powertrain. It's sort of the fault of the EPA...technically slower torque transitions yield better emissions. But a big part is keeping the response smooth for the millions of people who drive vehicles and don't care how fast it responds. Another big reason is smooth management of lash cross as you transition from accel to decel and vice versa. More gears in modern transmissions means more lash to negotiate...it has to be smooth and subtle. Both for driveability and health of the transmission.

    I can't speak to the exact reasons for HPT's omission of most torque shaping calibrations, but I would bet that those memory segments are not easily defined. Torque security is a huge concern for manufacturers, and by proxy, HPT as well...I doubt they'd be interested in lawsuits due to accidental death due to a throttle that hung WOT because of a customer that fat-fingered a value in the cal. Everyone in the industry remembers the Toyota floor mat issues causing cars to 'get stuck wide-open'...and it wasn't directly the fault of the manufacturers. These are my thoughts anyway...
    my 2010 LS3 Camaro, and many others have the Throttle Opening Rate table. I've slowed mine down, probably to about 3x faster than the one shown in this video since mine was like a cable... not good for a Whipple Blower.

    I think the table simply isn't found, HPT didn't put the time into it, or there isn't one that is configurable.
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    Quote Originally Posted by 10_SS View Post
    my 2010 LS3 Camaro, and many others have the Throttle Opening Rate table. I've slowed mine down, probably to about 3x faster than the one shown in this video since mine was like a cable... not good for a Whipple Blower.

    I think the table simply isn't found, HPT didn't put the time into it, or there isn't one that is configurable.
    Yeah I am familiar with that one. It's only a tiny piece of the whole throttle torque control algo though. Probably for the best that its not available for editing, to be honest.

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    Quote Originally Posted by kgschlosser View Post
    So we can blame the drivers that had the floor mats bunch up.. or we can blame the right people for the problem which is Toyota. It is not just a problem with the floor mats.. what if the driver has a heart attack and passes out or dies and their foot mashes down on the pedal.. any passenger in the vehicle should be able to take the car out of gear and coast the vehicle down to a stop. Toyota's design has just put all of the passengers in a casket. They were too blinded by $$$ because of the saving money that didn't get spend on engineering a neutral gear that could be shifted into and out of while the vehicle was in motion. The money they saved by making the braking system 1/2 the size it should have been designed. This saved them a lot of money and they didn't think about anything other then their wallets.

    Oh and I also do not believe that the vehicle can be turned off while it is in motion either.. Kinda strange that you can do that with a gasoline engine.. Most of this kind of information get swept under the rug. and the blame passed onto the driver. What do you think Toyota would look like as a company now had they been held accountable for all of these design "flaws".. Defiantly not the Toyota you see today.. Every single EV they made they would have had to buy back and scrap. I do not think that there would be too many people wanting to take the pitiful amount of money they wold get on the buyback (because you know the consumer is the one that would get it right in the poop shoot on that deal) and buy another Toyota with it.

    I am still waiting for one of these EV's to start having their batteries explode. kinda like the Samsung cell phones did. That will be the end of EV's for a while..
    I have much inside info on the Lexus issue with Mark Saylor crash. I trained several of the mechanics at that dealership when Lexus first came to this country. Same owner and we shared buildings. Some of it is direct knowledge and some is purely my opinion based on decades as a mechanic and dealing with dealer level "issues". Toyota had nothing to do with the crash. I really don't want to hash this out here. I'm not a Toyo fan but they got a raw deal on this. I believe that the sudden acceleration issue is 100% Bull***t.

    Two separate claims were TOTALLY dis-proven. One was so funny that a guy literally camped out in front of my dealership because a Toyo dealer was across the street to protest a Prius he didn't like. Funny thing is only one week after he was speeding up a long hill here locally and a CHP attempted a stop. He claimed sudden acceleration and later had to admit he made it up. We did all the work on CHP vehicles at the time so I often talked shop with Officers and the guys who worked on the vehicles so I had a broad range of knowledge from these guys. Amazing what they say after they get pulled over and what goes on behind the scenes.