eboggs_jkvl

This car is great but it does not like being started!

Car starts without a complaint. I back out of my drive and put it in Drive (either T or S) and accelerate slowly. It is at that point that the engine stumbles or hesitates. If I stay with the very light throttle it continues to be hesitant for at least a block. After that, no more problem. I also tried applying the throttle heavier to see if there was any change and the result is stumble or hesitation for about the same block distance and then it runs like a champ.

There is no way in hell that the dealer can see the problem without letting the car sit overnight and slapping a plug into the DTC immediately and start logging from start up. They only have 30 -45 seconds to find, see, note, catch, or whatever the issue.

I have EFILive and I can get on there and record "stuff" but I'm not sure what fields to monitor. Plugs? Spark? What else? O2 is open loop so nothing there. MAF might be good to watch.

OH hell, forgot the VIN 24280 (I'll catch hell for that!)



Elmer

Victor Dymond

I'm having the same issue

eboggs_jkvl

Really? Hm... What is your VIN?


Do you have the A6 too?

kp

Cant say I've ever experienced that, but I do let the car warm up for a minute or so before I take off.

eboggs_jkvl

I sit there and let the gauges figure out where they want to settle and then I pull out. No period of warming up is applied. Hell, I'm in Florida and a cold engine is "relative" down here!


Elmer

Higgs Boson

on a cold start initial drive for a couple miles it is not going to run as smoothly as when it gets warm. it is in open loop following a predetermined map/commanded AF ratio with no fuel trims. nothing a dealer can do about it unless GM releases a flash to reprogram this part of the fueling/airflow map. I can perceive a run quality difference in every car I drive regardless of make when it is cold start vs warm.

this is a result of having one tune for the whole world. generic. another reason a custom tune is nice.

of course this is outside any mechanical issue like a vacuum leak or the like. loose oil cap, disconnected PCV line, loose intake, etc.

eboggs_jkvl

That makes sense. One tune does NOT fit all that's for sure. As I said, perfect car after that initial run on the tables before the O2s start operating.

It's getting a tad on the "hotter than hell" side down here.

Elmer

kp

After my wife parking in the garage and my car sits overnight its about 90* + in my garage in the morning. It takes me a little maneuvering to get out of the driveway so even if I tried to get the car on the street in 30 seconds I couldnt. I have driven mine in 10 degree weather after sitting overnight and never had a stumble when cold but I do let it run for a bit before taking off.

I did notice sometimes after about 20-30 seconds the car runs rough enough to shake the car but it doesnt last long and smooths out after maybe 10 seconds. If thats happening when you are driving it then I can see it feeling like a hesitation/stumble.

eboggs_jkvl

Exactly the issue.

Higgs Boson

Hate to say it, but just ignore it.

kp

I probably couldnt get it out of the garage fast enough to try it on the street to confirm that 100%. But its possible..

eboggs_jkvl

Yeah, sounds right. I'm sure as hell not going in there and play with the tables to smooth it out. GM frowns on people "improving" on their stock tune and the "warranty" thing.

Elmer