Throttle Response?
07-28-2008, 07:38 PM
#1
Senior Member
Thread Starter
Join Date: 03-07-2008
Location: Essex, Maryland
Posts: 361
Throttle Response?
With the drive by wire it seems it takes longer than it should for the throttle to open after you floor the pedal. Anyone have any ideas to speed this response time up?
07-28-2008, 08:47 PM
#2
Senior Member
Join Date: 10-02-2005
Location: VA
Posts: 1,245
It's not the electronic throttle causing what you describe. The throttle will react quickly.
The OEM calibration has something called PE Delay, PE being power enrichment. The air fuel ratio will remain at stoic (14.7) for a few seconds of full throttle before the richer mixture begins. GM does this for both emissions and mileage numbers. Spark timing is also held during this. Some mistakenly think it's the VVT "kicking in" when enrichment happens.
A good ECM tune will fix this and make a big difference in both response and power.
The OEM calibration has something called PE Delay, PE being power enrichment. The air fuel ratio will remain at stoic (14.7) for a few seconds of full throttle before the richer mixture begins. GM does this for both emissions and mileage numbers. Spark timing is also held during this. Some mistakenly think it's the VVT "kicking in" when enrichment happens.
A good ECM tune will fix this and make a big difference in both response and power.
08-31-2009, 09:10 AM
#3
Member
Join Date: 08-24-2009
Location: Lake Norman, NC
Posts: 29
Yes, in my first week of driving my new 2.4 I have noticed the aggravating delay in response when starting off. From 2000 to 3000 rpm its like a dead zone! Really noticeble like the engine is starved for fuel & air.
So do I understand correctly that a chip or mod of the electronic tuning is the only fix for this? Air box and or exhaust have no effect?
So do I understand correctly that a chip or mod of the electronic tuning is the only fix for this? Air box and or exhaust have no effect?
08-31-2009, 09:52 AM
#4
Senior Member
Join Date: 04-07-2008
Location: Wisconsin
Posts: 1,051
CAI and exhaust will add some performance benefit. Trouble is that the computer will see differences and make adjustments to compensate. The real potential of using these will only be realized with a tune.
PCM For Less has tune for the 2.4. They a great reputation and are reasonably priced. Lots of Trailblazer/Envoy owners swear by them.
http://www.pcmforless.com/
http://forums.trailvoy.com/forumdisplay.php?f=116
PCM For Less has tune for the 2.4. They a great reputation and are reasonably priced. Lots of Trailblazer/Envoy owners swear by them.
http://www.pcmforless.com/
http://forums.trailvoy.com/forumdisplay.php?f=116
08-31-2009, 12:30 PM
#5
Member
Join Date: 07-29-2009
Location: Wichita, KS
Posts: 45
I've noticed that I have to be smooth on the throttle to avoid this lag. If I roll into the throttle then I don't usually get it, but if I just mash the pedal down I do. It's just a small change in my driving, and the car seems to agree with it.
08-31-2009, 02:32 PM
#7
Senior Member
Join Date: 08-11-2009
Location: Roseville, CA
Posts: 162
I noticed on my trip to Bodega Bay Saturday that there times where it seemed I had no punch in accellerating. Mostly on the highway where I was probably cruising at about 55-60, then needed to climb a hill.
No big deal, something I had to get used to.
Fred
No big deal, something I had to get used to.
Fred
