Backfire or Pop When Starting Cold Engine

If I leave the key in "on" for a few seconds before starting it happens less. I read somewhere on here that letting key be "on" for a few seconds makes for a quicker/smoother start.

 

I have noticed this as well. When it's cold out, and I first start my truck in the morning it pops. Oh well glad to hear that it's common and shouldn't affect anything.

 

Glad to find this thread. Guess by the 2015 models it still wasn't worked out. Mine just started doing this the past weekend. Not really that cold compared to others areas but cold for so-cal (30s at night)

 

Mine does it during the Texas summers too

 

Mine does this at random but not very often. Would like to see a video to confirm we are all talking about the same thing... maybe I will put one up. There does seem to be a correlation between the pop and colder start temperatures. My theory is that the colder temps require a richer fuel mix on startup, which in turn puts more raw fuel into the exhaust, which causes the pop when mixed with fresh air from smog pump. I also think the air pump adding air to burn the raw fuel in exhaust is what lights off the cat quickly. I don't see any other reason for an engine to immediately rev to 2200 rpm from a dead cold start.

 

Wow, this is an old thread, and what blows my mind even more is that it is a thread I started... Almost 7 years ago. I so rarely hear the popping noise when I start it up anymore, maybe once every other month. I’ve forgot all about the temperature of the air when starting. Maybe I’ll pay attention to it, but for something that happens once every few weeks/months, getting it on video wasn’t possible for me.

 

Ha..mine does it too from time to time. Good to know its common. Thanks for the post.

 

Your 2017 motor had to be rebuilt? Did you find out what was the cause? This is the first ive read of a low mileage 3rd gen 2TR failure

I hear this on mine sometimes during start up as well. Ive always thought it was normal

 

old thread i know but im having a similar issue with my truck and its never done this before until now....

2013 tacoma with 128k miles when it sits for a bit it will go to start fall flat on its face backfire and then slowly start up and run fine afterwards no loss of power or bad idle its just that startup... and its not all the time either in a week or two time frame its only happened 4 times i have no idea what the issue is or if its normal from what you all say its normal but mine is slightly different where it about dies then starts so idk...