2010 Avalanche, cold hard start

[riverbanks]

Yep, somehow the thread took a turn,like me,last night,too much nog,stairs looked bigger than they were,got a bruise on the butt bone,the size of a softball,more nog is helping,lol

[Rick Verdura]

Ok tsk it all started when I put sea foam in tank 

[Rick Verdura]

Before that it was fine

[riverbanks]

Time for a relearn, your fuel/alcohol content got messed up

[Jsdirt]

^^^ Yep, another common problem. I have to do this on my truck at least 4 times a year ... and I only drive about 2,500 miles in that time, or less. I always fill to full at each fill up, too.

[Rick Verdura]

So how do I relearn it

[Jsdirt]

Any bi-directional  scan tool should have a "special functions"  (or similarly named) tab that will take you to a list of options, one of which should be, "composition relearn".

 

My thoughts with this new information, is that you need to run that tank right down to empty, then refill to the brim. I had a similar thing happen when I dumped some stale 2-stroke in my Silverado that was a bit more far gone than I expected - ended up dumping a few cups of water in there, in other words. Took a couple tanks to get rid of the extended crank time, and erratic idle when cold. The Seafoam may have absorbed and dispersed some crap that was in the tank, or is just too heavily concentrated.

[Rick Verdura]

So how do I relearn it ok so my scan tool doesn’t have that option so I will try to run it empty and fill it 

[Rick Verdura]

My tank is almost empty the low fuel light is on going to change the fuel pump and clean tank out and try filling it with my truck it doesn’t have a pressure reg in fuel rail is it in pump 

[riverbanks]

Change the pump? did you get new pressure tester?

[Rick Verdura]

No but if it is the sea fome I am going to drop the tank and clean it out so I am going to change the pump 

[Rick Verdura]

Just in case 

[Rick Verdura]

So I changed the pump cuz my level sensor was off cleaned the tank filled it cleared the ecm all good for two days now