I am new to the forum and was directed here from the duramaxforum that I am on alot. A friend of mine has an 06 2500 with an 8.1L in it. Several years ago he had it tuned by a guy that has since retired. Overall he likes the tunes he has but at colder temperatures the truck does not start or idle well till it is warmed up. I have downloaded his tune and just started looking at things on it but since EFI Live is new to me I am not exactly sure where to begin. Under fuel/crank/start is where I am thinking I need to adjust to richen the mixture until the truck reaches a certain temperature after start. Can someone give me some pointers on where to begin. Any help would be appreciated.

 

It would probably help if you posted the tune file.

 

Have you verified that he has proper fuel pressure, fresh tune up, and properly working sensors??

 

Fuel pressure is good and truck is in sound working order. We just want to adjust the fuel mixture after start up so it will idle till it is warmed up.

 

Do you have a wideband? How long is it running before it starts running OK? When an engine starts it runs in open loop meaning that the fueling is controlled by the fuel map. Once the O2 sensors are heated the engine then runs on the air passing through the MAF. (This is everything I have understood, I might be wrong but am willing to help)

Do you know what the fuel trims are? Before I start tuning there are several things I do. Checking fuel pressure like you have is a good idea. I make sure the air filter is in good condition, and I clean the MAF. The MAF might look clean, but have a coating of oil on it especially if you are running a K&N filter. Are you able to post the tune so we can see it?

 

PM sent

 

Thanks a bunch to Gadetized for his help. The truck starts and idles much better after a start even down below 0F with is recommended changes although I did richen it up slightly more then he recommended to get it to idle correctly. When we took it on 500 mile trip last week the truck averaged 10mpg into the wind and 11 mpg with the wind at 70 mph. That seems on the low side to me, but then I am not sure what is normal for the 8.1. Just based on the looks of the tailgate of the truck I would say it is running plenty rich, but before making any changes, I was curious as to what people were using for a wideband? I would like to do some additional tuning on the truck, but want to know my air/fuel mixture as we go first.