drive by wire. how does it work?

[metal menagerie]

Being very old school, and just purchasing a new viper, I need to know how it's throttle works. After the problems with the Lexus, a stuck throttle with 600 hp could be a major problem !!! Help

 

[ViperGTS]

Remove the floor mats if you cant get control over them!
And, you can press the clutch and the brake pedals, can you?

 

[eucharistos]

to a noob's 1st post

bored in bavaria


(<----now 2011)

 

[eucharistos]

Being very old school, and just purchasing a new viper, I need to know how it's throttle works. After the problems with the Lexus, a stuck throttle with 600 hp could be a major problem !!! Help

congrats on the new car

are you new to cars "like" the viper, if so, drive by wire is your least safety concern

since mine is cable (mechanical), interested in the responses too

welcome to the board

 

[metal menagerie]

Hi, I thought it was a question I would like answered to. I guess you havn't look into what really caused the crash. Yes I'm new to cars like the Viper, with no throttle cable. Old School, drag strip. Dominator Holly carb, with two heafty return springs. I don't use floor mats. Nancy

 

[Warfang]

Hi, I thought it was a question I would like answered to. I guess you havn't look into what really caused the crash. Yes I'm new to cars like the Viper, with no throttle cable. Old School, drag strip. Dominator Holly carb, with two heafty return springs. I don't use floor mats. Nancy

Is your name Nancy or were you trying to throw some sass back? (we like sass around here... except for some of the other "Nancy's")

I don't think you have much to worry about safety-wise related to cable. Ease into a Viper slowly and get used to it before smashing the go pedal... actually, "smashing" the pedal on a Viper is rarely a good thing... smoothness is important.

 

[metal menagerie]

Yes, my name is Nancy. I guess my question was poorly explained, and by the way,I didn't get the Viper to ease into it. Gettting used to the Lambo was a bit of a chore, but not the Viper, pretty straight foward. Well, never mind my question, maybe I can explain another day another way.

 

[uvbnbit]

Are you saying you crashed a Lexus because of a stuck throttle??

 

[ViperGTS]

>>>Gettting used to the Lambo...>>>

Lambo...drive by wire...wait a moment...there was something ... thinking!

 

[09 Venom]

Yes, my name is Nancy. I guess my question was poorly explained, and by the way,I didn't get the Viper to ease into it. Gettting used to the Lambo was a bit of a chore, but not the Viper, pretty straight foward. Well, never mind my question, maybe I can explain another day another way.

Hi Nancy, congrats on the car , you'll love it. Ignore dumb*ss remarks!

To answer your question best I could. Older cars typically used hydraulic and mechanical sytems that required different parts to control the vehicles operation. Drive by wire replaces these parts with electrical wires. Sensors record the info and pass the data along to a computer which transfers the energy into mechanical motion. The Viper only has throttle drive by wire (there is also brake and steering units). The pedal uses a sensor to measure how much the driver moves the pedal. The sensor relays the information to the pcm/ecu. The pcm determines how much fuel is needed and provides this info to an actuator-a device that converts energy into mechanical motion. It then provide info to the injectors and electronic throttle bodies. So in other words, all computerized. Hope this answered your question.

BTW, If I couldn't drive a Viper then it would be a LamboGallardo.
Only other car IMO that has the look and speed of a Viper!

 

[GR8_ASP]

The situation with the Lexus was not about the throttle. It was about keyless ignition and shift by wire.

As it has been stated publicly the throttle pedal was depressed by being caught in the floor mat. the driver (a police officer) did not understand that and tried to turn off the vehicle by pressing the On/Off button and tried shifting into neutral. Neither worked because of specific control algorithms employed by Toyota. Apparently to turn off a vehicle at speed the Off button had to be depressed for some length of time and not just pressed. And the transmission could not be shifted to neutral at speed for engine/transmission safeguarding.

It tells you why it is so important to get the control algorithms correct and to learn of their operation before getting into an emergency situation. Somehow though Toyota has again gotten a bye with the press and not been put to the same level of scrutiny other OEMs would endure. I mean a floor mat recall (to remove floor mats)??? That was not the problem!

 

[ViperGeorge]

Congrats on the Viper purchase. Send a Private Message to a moderator with your VIN and get upgraded to Viper Owner status. Better yet, join the club if you haven't already then send a Private Message to a moderator with your VCA number. You'll find the regional clubs have a lot of events where you can drive your snake and meet others with the same passion for the car. Welcome aboard.

 

[propsail]

The situation with the Lexus was not about the throttle. It was about keyless ignition and shift by wire.

As it has been stated publicly the throttle pedal was depressed by being caught in the floor mat. the driver (a police officer) did not understand that and tried to turn off the vehicle by pressing the On/Off button and tried shifting into neutral. Neither worked because of specific control algorithms employed by Toyota. Apparently to turn off a vehicle at speed the Off button had to be depressed for some length of time and not just pressed. And the transmission could not be shifted to neutral at speed for engine/transmission safeguarding.

It tells you why it is so important to get the control algorithms correct and to learn of their operation before getting into an emergency situation. Somehow though Toyota has again gotten a bye with the press and not been put to the same level of scrutiny other OEMs would endure. I mean a floor mat recall (to remove floor mats)??? That was not the problem!

Very interesting. I've not heard that before. Thanks for sharing. What year/model? My wife drives an '07 IS 250. I have an '05 IS 300 as my daily.

 

[WILDASP]

Yes, my name is Nancy. I guess my question was poorly explained, and by the way,I didn't get the Viper to ease into it. Gettting used to the Lambo was a bit of a chore, but not the Viper, pretty straight foward. Well, never mind my question, maybe I can explain another day another way.

Nancy,
09 Venom gave you a very good technical explanation of how a throttle-by-wire works. I'm guessing that what you want to know is what it means for you in the Viper in practical terms, and whether or not there are any issues with it to be concerned about. Let me take a shot at addressing that.

The biggest problem Viper drivers seem to have had with the new electronic throttle (introduced in 08) was a lagging/delayed throttle response, especially under light throttle at low speeds/low RPMs. This was significant enough in early production 08 Vipers to require a PCM reflash to alleviate it. There were further changes made for 09 to improve this; however the 09 PCM or a reflash to the 09 settings canot be retrofitted by dealers to the 08 cars, due to the fact that the 08 drivetrain was not EPA certified with the 09 PCM/settings. Opinions vary as to just how annoying the problem actually is. One way around the issue is to replace the stock PCM with the Mopar "off-road" (read racing) PCM, which provides a more linear throttle response more similar to a conventional throttle. Note that this mod (a) will not pass smog testing, and (b) does have to be initially installed by a dealer (it requires the dealer computer to program the VIN into it, and a few other little details). That's the bad news; the good news is, that once it's done, swapping the stock PCM back in, and putting on a few miles to create a "history" for an OBDII smog check is a simple proposition, as is swapping the programmed Mopar PCM back in afterward. It's something you might want to consider if you are uncomfortable with the throttle response with the stock PCM.

Other than that, I haven't heard of any other issues with the new throttle. This one shoud not be a safety concern, unless the lag leads you to put your foot down too ******* cold tires, which really should not be a problem once you are used to it.

I hope that may help address your question, which WAS legitimate. Welcome, be safe, and enjoy!

 

[WILDASP]

Very interesting. I've not heard that before. Thanks for sharing. What year/model? My wife drives an '07 IS 250. I have an '05 IS 300 as my daily.

propsail,
2009 Lexus ES350.

 

[metal menagerie]

Thank you, that is what I needed to know. The Lambo I was refuring to is my Countach, and not refuring to it's performance, but being able to see out of it, and wondering if it's upside down, how the devil do you get out. Thanks again, Nancy

 

[ViperGTS]

ANY PIC's of your drive by cable COUNTACH?

 

[Chuck 98 RT/10]

Nancy, I might share your concerns with drive by wire. I feel much more comfortable diagnosing a mechanical cable than I do electrical wires and computers particularly at inopportune times like driving down the highway or tracking. But it appears we are stuck with it, hopefully it wont get stuck on us.

 

[WILDASP]

Chuck,
I'm not exactly thrilled with the idea either, but apparently it was a necessity with the new engine. I'm using the Mopar PCM, and at least so far, the throttle response seems to be predictable. Hopefully, there won't be any more issues.

 

[Warfang]

Hi Nancy, congrats on the car , you'll love it. Ignore dumb*ss remarks!

To answer your question best I could. Older cars typically used hydraulic and mechanical sytems that required different parts to control the vehicles operation. Drive by wire replaces these parts with electrical wires. Sensors record the info and pass the data along to a computer which transfers the energy into mechanical motion. The Viper only has throttle drive by wire (there is also brake and steering units). The pedal uses a sensor to measure how much the driver moves the pedal. The sensor relays the information to the pcm/ecu. The pcm determines how much fuel is needed and provides this info to an actuator-a device that converts energy into mechanical motion. It then provide info to the injectors and electronic throttle bodies. So in other words, all computerized. Hope this answered your question.

BTW, If I couldn't drive a Viper then it would be a LamboGallardo.
Only other car IMO that has the look and speed of a Viper!

Great job on the namecalling, sir. But I think Nancy knows what drive by wire is... she just wanted to know if it is safe in a Viper considering the Lexus fiasco.

GR8- great info. I've been wondering what the big deal was with a stuck floor mat. The whole story does seem a lot scarier considering I would have done the same thing as the officer. Any word if Toyota corrected the algorithms with their recalls or just took away floormats?

All this would expand on Nancy's question... how does the Viper's system compare? Considering a Viper isn't shift by wire, I would think you would still be able to shift into neutral. Save your life, kill your engine.

 

[Warfang]

Chuck,
I'm not exactly thrilled with the idea either, but apparently it was a necessity with the new engine. I'm using the Mopar PCM, and at least so far, the throttle response seems to be predictable. Hopefully, there won't be any more issues.

It's predictable, but is the response instant?

Maybe I'm imagining things but I remember vividly that when the gen4 came out, someone at SRT said that there would be a cable retrofit for the trackrats.

 

[ViperGTS]

No cable (I miss it too ), but the car is FUN (with the mopar PCM) anyway.
If you hit the gas pedal hard you will reach 100 mph on the short straight in no time

Where is(are) the picture(s) of the COUNTACH

 

[Phun70]

In addition to this response I would like to add, that the drive by wire technology also replaces items like the idle air control motor, cruise control servo and the throttle cables. It seems to work just fine, being a tech and running a shop I have never run into a system that would allow uncontrolled engine acceleration since the computer looks for two pedal position sensors signals, one with ascending voltage and one with decending voltage and matches those signals to two identical signals from the built in throttle position sensors in the throttle body, if any of the signals don't match, then the computer will enter a limited power mode and the car will be unable to get out of it's own way. Hope this helps to fill in any blanks for you.

Hi Nancy, congrats on the car , you'll love it. Ignore dumb*ss remarks!

To answer your question best I could. Older cars typically used hydraulic and mechanical sytems that required different parts to control the vehicles operation. Drive by wire replaces these parts with electrical wires. Sensors record the info and pass the data along to a computer which transfers the energy into mechanical motion. The Viper only has throttle drive by wire (there is also brake and steering units). The pedal uses a sensor to measure how much the driver moves the pedal. The sensor relays the information to the pcm/ecu. The pcm determines how much fuel is needed and provides this info to an actuator-a device that converts energy into mechanical motion. It then provide info to the injectors and electronic throttle bodies. So in other words, all computerized. Hope this answered your question.

BTW, If I couldn't drive a Viper then it would be a LamboGallardo.
Only other car IMO that has the look and speed of a Viper!

 

[Warfang]

In addition to this response I would like to add, that the drive by wire technology also replaces items like the idle air control motor, cruise control servo and the throttle cables. It seems to work just fine, being a tech and running a shop I have never run into a system that would allow uncontrolled engine acceleration since the computer looks for two pedal position sensors signals, one with ascending voltage and one with decending voltage and matches those signals to two identical signals from the built in throttle position sensors in the throttle body, if any of the signals don't match, then the computer will enter a limited power mode and the car will be unable to get out of it's own way. Hope this helps to fill in any blanks for you.

Good to know... so would you say the Lexus issue was just a 1 in a million fluke?

 

[WILDASP]

It's predictable, but is the response instant?

Maybe I'm imagining things but I remember vividly that when the gen4 came out, someone at SRT said that there would be a cable retrofit for the trackrats.

Warfang,
It seems to be, with the Mopar PCM; I'm not sure about the stock PCM, since I had the Mopar installed (along with exhaust, etc) before the car was shipped to me. Most of the comments I've heard, were about the stock unit at low rpm, which wouldn't be a problem on the track. I didn't hear about the idea of a cable retrofit, so don't know if that is/was a viable alternative.

 

[RTTTTed]

Cable would not be able to retrofit if the AIS is non-existent on the DbW Throttle bodys. Computer programming would not be there for a retrofit for older manual TBs either.

Ted

 

[09 Venom]

Being very old school, and just purchasing a new viper, I need to know how it's throttle works. After the problems with the Lexus, a stuck throttle with 600 hp could be a major problem !!! Help

I think Nancy knows what drive by wire is... she just wanted to know if it is safe in a Viper considering the Lexus fiasco.

Didn't want to assume she knew. I didn't mind typing it if she didn't mind reading it. You didn't have to read it!

 

[WILDASP]

Cable would not be able to retrofit if the AIS is non-existent on the DbW Throttle bodys. Computer programming would not be there for a retrofit for older manual TBs either.

Ted

Ted,
Thanks for clearing that up. I missed the original discussion of the idea, so don't know what was asked/said, but that explanation makes complete sense - two completely different (and incompatible) systems.

 

[Warfang]

Cable would not be able to retrofit if the AIS is non-existent on the DbW Throttle bodys. Computer programming would not be there for a retrofit for older manual TBs either.

Ted

Thanks for clearing that up.

 

[metal menagerie]

Here is the pix