Pump adjustment question

[Niki]

What controls fueling before you get into boost, just the full fuel screw? My 5 sp truck when starting out blows pretty big clouds in the lower gears, but if you get on it at a higher RPM or when you're already going, just a wisp of smoke because it gets into boost quicker. I'm doing a lot of city stop and go driving and would like to cut down on the cloud and probably save a few bucks in fuel too. The guy I bought it from really didn't know what was done to the pump, the collar and cap is off the full fuel screw, but that cap is still on the top of the AFC housing and the high idle stop was untouched until I messed w/ it. Thanks

 

[HRDROKN]

What controls fueling before you get into boost, just the full fuel screw?

The AFC assembly limits fueling at low boost... . and there are a few ways that you can go about adjusting it. i. e. rotating the fuel pin/diaphram, adjusting the star wheel or adjusting the "smoke screw" on top the AFC.

 

[Niki]

I had it all wrong, I thought the AFC added fuel under boost. which way would I turn the starwheel for less smoke before boost?

 

[bgilbert]

Starwheel up top, lefty loosey lean/less fuel before boost. Starwheel bottomed out, righty tighty rich/lots of fuel before boost. Back off the fuel screw a turn as well if you want to save on fuel. Or do that if bringing the starwheel all the way up doesn't get rid of the low end smoke. Thread the smoke screw on top the afc cover all the way up too to limit low end smoke.

 

[Niki]

Thanks Bill, exactly what I was looking for.

 

[dpuckett]

Smaller exhaust housing can help on bottom end spool up. As long as you are under ~250hp, a 12cm gated housing (94-97 take off) can be a BIG help. But if you do a lot of towing, it may not be best for long grades.



Daniel

 

[Niki]

All I'll ever tow w/ the truck is about 6K#, I may upgrade my turbo and injectors, not sure yet though. Just trying to get it less smoky on the bottom end now.