12 Valve Dog Off The Line
 

First of all thanks for all your help for my 12 shuttering problem.

The timing was adjusted to 16.5 which they told me was good for this altitude, Denver 5280 above sea level. Took care of the shuttering problem I had but now the truck is very slow off the line and takes forever to create boost even when cruising on the highway and I punch it it will take awhile to build boost. Not sure where the timing was set when I had the shuttering problem but it didn't take that long to boost. For a refresher I had to replace the turbo with an aurora 3000, changed the injectors to 270's, replaced the air box with AFE stage 2, changed fuel plate to number 10 and finally replaced tranny with ATS with five star torque converter. It blows a lot of black smoke off the line even after I turned the star knob all the way back torwards the firewall.

Any ideas how I can get off the line quicker?

Thanks
Winston

I would think with that turbo that your exhaust should be fairly clean.

Having the starwheel all the way back is part of your problem, IMO.

Try sliding your AFC housing forward a bit, like maybe almost all the way forward. Then put your starwheel at about the 1/3 to half way point.

Where is your plate set at? Is it all of the way forward? You should slide it back a bit if it is.

The purpose of the AFC is to hold back the fuel until you reach 10psi of boost. It does this so that the turbo has a chance to light and doesn't flood the engine with fuel that it doesn't have enough air to burn. Taking some time and tuning the plate location, AFC location and starwheel location can make a big difference.

I set the fuel plate at about 1/16" back from full forward when I originally installed it. I think I set the AFC housing all the way forward, read some threads on this site to know to do that.

I will move the star wheel back to the half way position. I have been adjusting it mainly from front to back because of the heavy black smoke I have been getting off the line.

I will try moving the fuel plate back a little bit also. I noticed the small tube coming from the intake to the back of the AFC housing, I am assuming this tube is what tells the AFC it has boost. Not sure exactly what it does when boost occurs. Is this what pushes the arm to follow the fuel plate?

Thanks for your help, the more I understand about the way the injection system works the better I can trouble shoot and try to figure out what's happening and why.

no that line controls the boost pressure to your wastegate and to turn up the star wheel it has to be turned toward the block not the fireway i did this when i started bombing and my truck wasnt building boost fast enouph then i turned the star wheel toward the block as far as i could, it built great boost, now i dont have to worry about it since now since i have so much performance done

yes there is a line from the intake housing to the back of the afc this does exactly what you think it does, boost builds it moves the afc arm and lets fuel go. DD

This man is correct. At ~10 psi the boost contained in that tube pushes the AFC foot all the way forward. Check that it is in good shape and not leaking.

Ok I moved the fuel plate back about 1/8" from full forward, made sure the AFC housing was all the way forward and moved the star wheel to approx half way. This seemed to help however still takes a while to build boost. I get about 33psi at full boost but blows a lot of black before it starts to build.

It has been between 98 and 102 degrees outside for a few weeks, could this have something to do with it? It's my work truck so it really only get driven during the day.

If I keep moving the star wheel forward what will happen?

you cant hurt anything by maxing that star wheel out you will just build more boost faster thats what ive done to all my work trucks that have 12vs