wilderness

Well I straight piped through my cat today, you could'nt even see through it with a flash light! So I actually cut the cat out and ran it straight piped to my shop to weld a new piece in to the muffler. I know what you are thinking why did'nt I go ahead and 4' it all the way back? I'm sure you know tha answer is, $$$$ (or lack there of) So anyway when I drove to the shop straight piped, it sounded like a Peter Built with a load of timber until the turbo spooled up then it sounded smooth. It actually sounded bad like it was having a hard time burning fuel. After I got it all back together I slid the AFC forward all the way and cranked the star wheel all the way out. Now it does'nt run like it should. I have black smoke when in neutral and I tap the throttle, but it does'nt have the go it should. So is sliding the AFC considered moving the fuel plate or do I have to pull the AFC and physically slide the fuel plate forward? When you are straight piped does it flutter when you are in low psi turbo? Thanks, Chad

kawi600

Im pretty sure this is right, someone correct me if Im off.
Moving the AFC itself forwards on the pump body changes the range its active in, lean or rich with sliding it away from the cab being richer on fuel. the arm from the AFC just keeps the governor arm from reaching the plate when its active. Adjusting the star wheel does this also but this is the main adjustment for it. Both control fuel level before the turbo kicks in.
Moving the plate forward adds fuel across the whole range when the throttle is down enough for the governor arm to start touching the plate
Im surprised it smokes with just the AFC, mine didnt smoke until I added 191 DV's. I think your truck is 160 or 175 stock? think thats 131 DV's

wilderness

It's not alot of smoke, just when I tap the throttle real fast. The truck still does'nt smoke when I take off. I really don't care how much smoke it has I prefer power over smoke. The truck smells really ritch all the time, especially at idle. That being said I should probably wait to add fuel if it's not burning what's already there. What would cause one to be ritch at idle?

kawi600

rich at idle would be the afc setting I think. They all stink pretty bad at idle IMO. Mine is about the same from when I bought it stock as far as the fuel smell at idle. If I mash the pedal I do get a bit of smoke but not enough to cause visibility problems.
Mine also has no cat on it, as well as some flowmaster muffler the PO installed. Its got the stock 3" pipe, but in stainless steel so Im really reluctant to upgrade to 4" when this pipe hasnt got any rust on it. Plus I dont have enough fuel and air yet to get any real benefit.

Common

After you run a str8 pipe, your exhaust will smell different... actually stink...

schaef_12

Sliding the Afc forward, and spinning star wheel towards the engine controls pre-boost fuel, witch might result in very little seat of the pants horsepower. The main adjustment is sliding the fuel plate witch will have alot more "go" than just sliding the afc. As far as the sound goes when you cut the pipe underneath the cab the exhaust will echo really bad underneath your pickup and cause the "flutter" you are describing.