Hi,
My sigs got my mods. I just changed the star wheel to all the way down and smoke screw to slightly in. Driveability is better and mileage is a bit better than how i had it before. BUT Ive been loosing milage. My best since the summer fuel switch is 16.5. This is a mix between city, highway. Occasional throttle usage. When I get heavy on the pedal, 12-13 mpg is no problem. Especially with winter fuel. Its running normal EGTS, and boost levels. About 5-10 psi doing 70-75 mph on mostly level (slight grade).
Think my timing is too far advanced for the stock injectors?
Think its time for new ones? (rebuild not an option, local shops a joke)
Any other suggestions?
305000 kms on it <--not converting that to miles, sorry
It seems bone stock was better on the fuel than it is now...

Thank you...

 

Tighten the star wheel up some, and put the smoke screw back where it was or even further out. With the main fuel screw in that much you don't need the AFC to be set so aggressively.

 

Mileage is equal if not better with the star wheel down and a little smoke to er...? Go figure. I thought with no fuel going through it would get better economy.
She dont smoke unless i make her smoke. Minimal smoke at spoolup (light throttle).

My best so far this year is 17mpg unloaded. That was on the highway doing 110-120. But it seems to get that in town too. And with the boost controller blown off (although temps were about 100 degrees hotter than normal)

I have noticed a slight haze at idle lately tho. The smoke screw is pushing the fuel pin down about 1/16 of an inch. I checked with it out.
I need a smiley with a gun to its head...

 

From what I hear around the lunch-table, regardless of engine brand or truck model-year, almost without exception, everyone says they lost from three to five MPGs with the mandated switch to ULSD fuel.


I ain't no scientist; but, in my way of thinking, wouldn't it create less polution to just burn X amount of plain old fuel to go X distance, than to burn half again as much ULSD to go the same distance ??

 

Mine was hazing at idle, getting poor mileage & rattling loud. Backed timing down 1/16 & it fixed it.

 

I thought increasing the timing was suppose to help mileage???

 

Sounds like he went over the edge. Like any good thing, timing can be taken too far.

 

Yeah, I eat too much watermelon one time.

 

i hope that avarage speed of 110-120 was in km . if not i would not be complaining about 17 mpg

 

hes from canada so i would think it is
Joel

 

If my truck did 110mph im pretty sure it would start to take flight.

Um, whats a good bump? The marks are about 1/4" apart.
It rattles slightly when its cold out and the engine is cold. Any suggestions on how far to pull it back?
Thanks

 

just enough,

most of use only have about an 1/8 bump towards the head

 

I only get about 15-16mpg when I drive when my dad borrows my truck he used to get 21mpg but i think its gone down a bit since he uses it a fair bit and switching between him and I its about 15 average, Its probably the ULSD causing that.