Drive By Wire?

[jaybee]

The operation I run has seen a lot of short-term help since the beginning of the year, meaning a lot of hotel rooms and rental cars. I've driven almost every one of those cars at one point or another and learned some interesting things about currently available cars. Much of it isn't worth talking about here, but something caught me off about the most recent car, a Chevy Cruze.

Seems like a pretty decent car, but the transition from off throttle to heavy throttle really bothers me. You put your foot down and the initial response is OK, then it takes off much stronger.

Does this have something to do with the drive by wire programming, slowing the throttle response to keep idiots from getting in over their heads? If so it's REALLY annoying.

[enjenjo]

I have the same problem with my Escape, nothing, nothing, then full throttle. It bugs me too, but I have gotten used to it.

[Crosley.In.AZ]

the short answer is yes.  Programing produces a slow opening throttle blade.

A friend of mine digital video recorded a throttle body off GM inline 6 4100 engine in a stock config and then with altered programing at 100% throttle control.  A very big difference in how slow the throttle blade opened, then the instantaneous  opening

[unklian]

Been doing some reading on this. The Ford guys call it "dbw lag".
DBW meaning Drive by Wire.


I haven't tried this yet, but it sounds interesting.
Still researching.
Might be an urban myth, proceed at your own risk.


http://www.f150online.com/forums/v8-engines/435069-try-throttle-calibration-efi-engine-works.html

http://www.f150online.com/forums/2009-2012-f-150/434603-throttle-response.html

http://www.f150forum.com/f4/throttle-resonse-fixes-5-4-a-71539/

[wayne petty]

for GM guys with drive by wire.. i spotted this a some time ago..


if you click on it .. it downloads a 8 page PDF file on GM drive by wire throttle relearn procedures.. and which models get which procedure..

the original is probably somewhere on the napa web site..


http://www.google.com/url?q=http://www.gadgetmangroove.com/index.php%3Foption%3Dcom_phocadownload%26view%3Dcategory%26download%3D8:gm-drive-by-wire-throttle-body-relearn-procedure%26id%3D2:certified-gadgetman-documents%26Itemid%3D429&sa=U&ei=aHT_T8qRNu_22AWlu_ipBA&ved=0CBgQFjAC&usg=AFQjCNEgwRsaWB9IpH3eoYQCNfO4LUR9Yg



and for those who have purchased one of the newer gm SUVs that was supposed to get over 30MPG.. but barely get 23..  i would like you to look under the hood and see if the ac clutch is actually cycling..  i have seen a post or two.. that the compressor is engaged even with the AC off.. and it never cycles off.. this could be the cause of the reduced fuel economy..

the owners have also complained about slow take off.. so i am thinking they are mashing the gas pedal.. to get it going.. only to have the throttle actuator slowly open... by that point.. the fuel injection is at FULL Enrichment..  so there goes the fuel economy..

i have not gotten my hands on one for a test drive..  or been able to take a ride in the passenger seat with my scan tool plugged in looking at the live data stream..

oh... and for those who have VW products in their family.. you will want to read this also.. if you ever have to disconnect the battery...

http://wiki.ross-tech.com/wiki/index.php/Throttle_Body_Alignment_(TBA)

[teal32]

I'm running an '06 LS2 in the '40 Chevy, using the DBW. I have the same lag as everybody else. Lokar makes a "Drive-By-Wire Electronic Throttle Control Pedal Assembly" that they say gives 3 time better performance. It's pricey, I think around $300 plus a pedal assy. The lag keeps me from gettin a little frisky now and then, so I figure it save me money. But, I will probably change over to it this Winter. It just doesn't feel right to have the lag.

[jaybee]

I'm not a bit sure the Lokar pedal will fix it for you. The lag is probably programmed into the PCM. The DBW pedal is just a position sensor, like the Throttle Position Sensor.

Looks like there's plenty of interest in fixing it, though, and plenty of options depending on the engine/computer/car combination.

Your best option since you're in rodding application might be a "mail order tune." You pick your options, mail the unit to the tuner. He reflashes the programming and mails it back.

[unklian]

Tried this fix today, on my '05 Crown Victoria.

Works very well. And the price is right.

The Ford guys call it "dbw lag". DBW meaning Drive by Wire.


http://www.f150online.com/forums/v8-engines/435069-try-throttle-calibration-efi-engine-works.html

http://www.f150online.com/forums/2009-2012-f-150/434603-throttle-response.html

http://www.f150forum.com/f4/throttle-resonse-fixes-5-4-a-71539/

[wayne petty]

drive by wire throttle lag eliminator..


http://www.jegs.com/p/Sprint-Booster/Sprint-Booster-Drive-By-Wire-Throttle-Delay-Eliminator/1334709/10002/-1?viewAll=1

not cheep... perhaps there is more products out there..

[unklian]

"Throttle Calibration

Throttle calibration can substantially improve throttle responsiveness over "factory standard." Many people notice what appears to be sluggish throttle response or a "dead area" at initial accelerator depression. Throttle calibration can take care of these.

1) turn the key in the ON position (don't start the engine)
2) press the gas pedal down slowly all the way down
3) let go of the gas pedal fast so it come back up
4) turn key into the OFF position
repeat steps 1-4 two more times then start engine.

Most drivers notice an immediate change in throttle response, but depending on your driving style, you may need to repeat this procedure periodically due to the computer's adaptive programming. You likely need to repeat this procedure any time the battery is disconnected."

From:


http://www.f150online.com/forums/v8-engines/435069-try-throttle-calibration-efi-engine-works.html

[Carps]

The drive by wire systems are calibrated for best emissions performance which is why you get the lag effect.

They can be reprogrammed to work at the speed of a mechanical linkage but you'll need some good 'puter skills to rewrite the programs.

[jaybee]

Hadn't thought about emissions...but of course manufacturers are ALWAYS thinking about emissions.

In terms of skill required for reprogramming, the great thing is that someone is always working up ways to do that for anything with a smidgeon of popularity.

[Warpspeed]

Sounds like turbo lag...... without the turbo........

Only thing I can think of beside emissions, might be fuel economy.

If you instantly crack the throttle wide open, you are going to have a lean stumble, unless you also tip in a massive sudden (accelerator pump like) fuel squirt.
That could use a lot of unnecessary extra fuel with really aggressive driving, and screw up both emissions and drivability if it is not done exactly right.

Now if you slow down the rate of sudden initial throttle opening, it may be possible to better control the A/F ratio during sudden initial acceleration, and use less fuel.

I dunno ??  
Just guessing really.

[Crosley.In.AZ]

I think the drive by wire lag is dangerous.  

My plan is to drop back many years for a daily driver so my foot is connected to the engine with a cable or rod of some type

[wayne petty]

Sounds like turbo lag...... without the turbo........

Only thing I can think of beside emissions, might be fuel economy.

If you instantly crack the throttle wide open, you are going to have a lean stumble, unless you also tip in a massive sudden (accelerator pump like) fuel squirt.
That could use a lot of unnecessary extra fuel with really aggressive driving, and screw up both emissions and drivability if it is not done exactly right.

Now if you slow down the rate of sudden initial throttle opening, it may be possible to better control the A/F ratio during sudden initial acceleration, and use less fuel.

I dunno ??  
Just guessing really.

well on that thought... it would keep the fuel control system within CLOSED loop.... so its under as much fuel control as possible...

closed loop is where the air fuel ratio or short term fuel trim is calculated by looking at the various oxygen sensors.. keeping the cats fed with the proper slightly rich mixture to keep them HOT and working...  this is why OBD2 cars usually get less fuel economy than OBD1 cars could get...

open loop is where the fuel control is reverted to preprogrammed numbers and sensor inputs from the MAF/MAP,  TPS, ECT, RPMs,   this usually happens at hard acceleration..


i wonder if the drive by wire throttle closes for shifting.. there is one tow truck in my area... speeds everywhere.. heard it go up bronson from sunset just the other day...   FULL THROTTLE UPSHIFTS.. i would hate to be that transmission.. i won't mention him getting airborne taking a short cut through a gas station at a red light..

i would expect that some brilliant person is going to come up with an exhaust cut out..  that allows regular driving conditions to flow through a single cat with a moderate size... and when needed.. the cut out opens and allows the extra exhaust flow through the parallel cat..  this would result in cleaner air out the tail pipe...

i wonder when someone is going to come up with an electrically HEATED monolith cat..  or using something like a microwave to super heat the exhaust flow coming into the cat..    even wrapping the monolith in an inductive heating coil.  this could also be done on the  exhaust flow into the cats if enough heat could be transfered to the air.. perhaps with a grid in front of the cat for the inductive coils to super heat..

this will probably go in the waste can with my other ideas like PM generators..  that have many field windings but have an odd number of magnets compared to the winding cores.. so there is little JOGGING or alignment of the magnetic fields with the cores so there is less torque needed to turn the shaft at any speed..  spin a distributer shaft that has a magnetic pick up and reluctor..  you will feel the effect i want to get past...

wait.,.. i got way off track...  i will now remove my foot from the throttle and back off..