Well i am driving up to colorado this christmas, and i will be staying at my Wife's Father's house which is roughly at 8000ft. My tune is currently set up as Open Loop/MAF. Which i have loaded COS#3, and i am commanding 15.5ish in the light cruise areas... I am just wondering if i will be OK, driving it like that... Also I am tuned for 93 octane and i believe the highest i can get in Colorado is 91?

Thanks in advance.

 

corey the highest i seen in colorado was 91 but it's ALL got ethanol in it as well if that means anything to you...i ran open loop speed density and the higher in altitude i got the leaner it got...it got so lean that the truck wouldn't even run. i had to unplug my IAT sensor so that it would default to thinking it was really cold outside and add alot of fuel

 

i think i ended up adding close to 10% across the board on my VE table

 

Glad you brought this up, because I'll be making a trip to Colorado as well at the end of the month for the New Years' time frame...

 

Ya our gas in the DFW area has ethanol in it now, so that is no biggie. I wonder since i am running a MAF my fueling will be OK. Or i wonder if i need to adjust Barometer parameters...

 

Supposedly Shell V-Power contains no ethanol...

 

interesting, i always get my gas at QT down the street or Chevron down the street. both have stickers saying, "May contain Ethanol"..

 

Ya i get it at QT most the time... but i read a thread about a guy saying he saw a sticker about it at a Shell and emailed the company and they confirmed it... i can't remember what flippin forum it was on now. hahaha

 

Yep, Like Dan said, Both my truck and Thunder550 when he come up here in OLSD will would lean out. Same thing happens then I go down in elevation, gets richer. It's like the PCM over compensates for the difference in Bero pressure. I'm not sure how it would be with running a OLMAF tune though, would be interesting to see. The reason you only find 91 up here is because with the less dense air at altitude, you don't need/can't use the higher octane fuel, so they just don't sell it. Our reg here is only 85. So bring you software and be prepared to make adjustments, or just put it in CL.

 

Since you have a maf I would think it would adjust. I drove mine up there when it was still fairly new, still running a maf and front 02s but I didn't have a problem. Of course I didn't have a wide band to confirm what was goin but my gas mileage stayed the same so I just assumed...