Cold, cold No start... pedal to floor... starts
 

New to me '06 Envoy w/ 4.2. 87k miles. I don't even have plates yet but it was in the way last night at -4 degrees F so I was looking forward to the test. It turned over and lurched a couple times but didn't start after 3-4 attempts. I reluctantly put the pedal to the floor and tried again. Fired right up but idled rough for a couple minutes until it smoothed out and ran fine. This usually isn't the routine with fuel injection but it's worked for me with other cars. Comments? Thanks, C.
ps I have 3-4 secondary air injection codes present and am working through that.

the air injection may cause issues im not how that works on newer vehicles. i do know alot of people have problems with the 4.2's with carbon build up on the back of the throttle body butterfly, and you have to take it off and clean it real good. drive by wire vehicles dont have separate idle circuits/valves so they are very sensitive to carbon in the tb at idle especially

Sounds like it had a flood issue and needed to go into clean out mode. Could be a leaky injector nozzle.

jwfb, I will clean the tb as I have seen this mentioned. Racer, does this fuel injection have a "7th" cold start nozzle? I've had cars with a cold start nozzle separate from the cylinder injectors. I will clean first, work through my Air Injection issues and go from there. Thanks, C.

No it doesn't have a cold start injector like the Toyota.

I'm kinda curious how he got it started to begin with when he had it "floored" while starting. Aren't GM's programmed to turn OFF the injectors when the PCM see's 90% or better TPS while cranking? Or what GM calls, "clear flood mode".

That is why I think it was flooded.

Things that can cause a flooded condition on a fuel injected engine are leaky injectors, ruptured fuel pressure regulator or a bad or shorted engine temp sensor or even a bad mass air flow sensor. It could of been a fluke thing. My wife's SRX had flooded on me twice in the 5 years we have owned it and it doesn't set any codes when it does it.

i think its something to do with the dbw throttles because as the carbon builds up the tiny air gap gets blocked, that will be over rich and no air without the iac like the older cars had. and you have to open the throttle some before it will start