Welcome!

By registering with us, you'll be able to discuss, share and private message with other members of our community.

SignUp Now!

Colder = Leaner?

NHXRUNNER

"New Hampster"
Staff member
Joined
Jul 30, 2007
Messages
7,995
Reaction score
303
Is AFR calibrated to a certain ambient temperature? I don't remember going lean last winter. But since the weather has shifted into the low 30s and 20s all of a sudden I'm seeing 12s in boost and I find myself staying out of boost now. Is it normal? I'm running the 2.825 pulley and no FPR mod....

Could it be related to a plugged up fuel filter? I did the fuel pump upgrade just prior to installing the blower (1.5 yrs ago) and haven't ever changed it.

Thoughts?
 

autobodyX

Active Member
Joined
Aug 8, 2010
Messages
869
Reaction score
36
Changing the filter would be a good place to start. I see a lot of complaints this time of year, many times it’s summer blend gas in cold weather. Do you have fresh fuel in the tank?
I had trouble with the fuel hose in the tank cracking. The Leak slowly got worse, and truck got hard to start, lost power,and run lean.
If you notice the engine spins over longer before starting, that would point at a cracked line.
 

NHXRUNNER

"New Hampster"
Staff member
Joined
Jul 30, 2007
Messages
7,995
Reaction score
303
Fresh fuel, no hard start issues, no lost power....I threw in the FPR mod and my AFRs fattened right up. Hopefully I can pull that off once I get the filter replaced.

What should I be looking for in fuel trims? And what will that tell me?
 

wolfpack_5150

Jangley
Joined
Jan 13, 2012
Messages
303
Reaction score
17
Fresh fuel, no hard start issues, no lost power....I threw in the FPR mod and my AFRs fattened right up. Hopefully I can pull that off once I get the filter replaced.

What should I be looking for in fuel trims? And what will that tell me?
Lmao, yeah i notice a large lack in mileage whenever i try the boost reference (sometimes i try different things in diff weather or if im hitting large elevation changes). I mean u never know unless u try, plus we all like to tinker right?

With boost referencing i went from 11 or 12s to a rock steady 10 or maybe lower (gauge only sees 10:1) with the boost reference. Def lost some get up and go.... felt like the truck was drowning in fuel

That said, in about 30k miles i dumped some nasty fuel out of my fuel filter (the one from urd). It was dark, with alot of sediment on the bottom of the glass i poured it in.

.
 

woodex m.e.

Member
Joined
Jan 25, 2014
Messages
65
Reaction score
2
Good new. Its just simple fluid dynamics. When the air gets colder since our superchargers dont have a boost limiting bypass, we increase boost as the temp gets colder. You are technically running leaner because you are forcing more air in. Im in maine and i run the fpr mod all winter otherwise i lean out like you. Once its warm out again no problems. One day i gave it the beans and it was -20 out and i had about 1.5 psi more boost than at 40 the day before.

There may be other small factors but thats the main thing going on.
 

NHXRUNNER

"New Hampster"
Staff member
Joined
Jul 30, 2007
Messages
7,995
Reaction score
303
Just would have thought the ECU would adjust for it......
 

woodex m.e.

Member
Joined
Jan 25, 2014
Messages
65
Reaction score
2
What the hell? Where have u been hiding. Where in Maine are you at?

I lurk about once in a while. Not super often any more, things seem to be slow here lately. Also im a TRD OR and not an X runner so i spend more time just reading. I am in Brunswick, but im originally from Caribou and frequent there during the winter.
 

woodex m.e.

Member
Joined
Jan 25, 2014
Messages
65
Reaction score
2
Just would have thought the ECU would adjust for it......

Thats the thing, i dont think it can. I think its maxing out the injectors and their signal and thats why the oem fpr mod seems to do the trick. If the weather is cold enough its almost the same as running a smaller pully.
 
Top Bottom