First off I have a 95 12v
Full gauges
Boost elbow
Was told (not sure) 150hp injectors however not confirmed yet.
Built trans, 4x4
Bd HD torque converter with lock
Bd exhaust brake with 4" full exhaust
BHAF
Stock turbo, no shaft play
Reading good fuel pressure 18-22 psi IIRC on gauge, only dropping a little under full throttle



Background:
In an attempt to turn the truck up a bit I installed a boost elbow pre set to 33 psi. Also slid the factory fuel plate and AFC housing forward. This barely made any difference at all. Truck is still lethargic and boosted no more than 22-23 peak leveling to 20psi, hardly any smoke. I decided to try to go to the other extreme and work backwards. So I cranked the star wheel all the way forward, blocked wastegate line entirely, removed fuel plate and tried it again.. Minor improvement, tiny bit more smoke, still no more boost... I'm stumped. I expected an obnoxious 12v as seen on YouTube haha, this was not my ultimate goal but I figured I could tune down from there to control smoke and keep as much power as possible. Now however, I'm concerned that there may be another issue. I have checked the boost reference line and replaced brass fittings to AFC, checked for loose boots and haven't found anything obvious. I am just at a loss as to how to go about trouble shooting everything. I have searched and turned up mostly no boost problems or no power, this is not the case. I am getting boost and power, just not as much as I should be. I am concerned it may be on the fuel delivery side of things since the AFC mods should have resulted in a teenage smoke show, but I get little more than a dark puff at full in launch and instantly clears. This would be great if it came with 33psi of boost and full power.. I would love for any advice you may have. I do all the work I can myself, but don't have endless funds to play the pick and replace game. Please lend your knowledge. Thanks everyone

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Also would like to add, EGT's never get very hot at all, all into the throttle held to the floor and still won't get very hot

 

I don't think you're getting enough fuel delivery. Your EGTs should be screaming with the plate out and AFC forward. Where are you taking the FP reading? How is your filter(s)? I've heard of many 12V's with lower pressure than yours, but I know mine has never been that low. It idles over 20psi, cruises around 30psi. Loaded it dips down to 25psi sometimes, but always comes back up. This was the case even before I started messing with the pump, and it's only gotten more stable as I've turned things up. I doubt I have any real answers for you, but I'd start by checking the filter and prefilter if you still have the stock arrangement, and a Tork Tek over flow valve. It's a cheap part change that could make a difference. Good luck.

 

ok how many turns have you givin your star wheel .... or have you adjusted it at all ?
does your truck some at all ?
what brand of gauge are you running ( have had some real cheep ones give many false readings ) ....
mine is timed @15.5* FF plate star wheel almost spun loose ( spin twards engine to increase fuel ) and I haven't touched the smoke screw ... I pulled my Fuel plate and lifted the head .... hat to put it back in , blew the HG and its leaking under the thermostat housing .... make sure you have studs installed before you get too carried away ( more than 30-35 psi) is gonna be an issue and studs will keep it from lifting the head.....
keep us posted

 

Alright I figured if go through and take care of a couple of issues mentioned before proceeding. So as of today I have changed the fuel filter and replaced the overflow valve with one from tork tek. My fuel pressure gauge is good and is reading 25psi-30psi at idle and under load now and the needle is very steady. The AFC housing is forward as far as I could move it and I adjusted the star wheel forward until it was far under and not able to be turned anymore. I assumed the new higher fuel pressure would have solved my problems, however it has not. The truck does smoke some, but doesn't roll coal like I expected given everything was turned up. Again I'm not going for a smoke show here, just was going to use it as a starting point. I still am unable to get full boost pressure out of it. It simply won't boost that high, I'm thinking boost leak? Or maybe there is a leak in the system elsewhere preventing full fueling from the AFC housing? I'm not sure where to start. I did notice that a couple bolts on my housing were loose today, I tightened everything up, but one is missing (the tamper proof one or whatever) could pressure be bleeding off at the AFC and not causing full rack travel?? I'm stumped

 

Check the hose from the afc to the manifold again. On my 8.3 its only 3-4 inches long and was worn through in 2 spots. Yours is much longer on the 5.9 I believe and its easy to check.

 

okay will do. I also noticed that my boost line (running to the gauge) is just a rubber hose, not a hard plastic line. Could the boost cause that line to swell up or could potential damage to that line allow pressure to escape?

 

that could do it too.... could be balooning and leaking somewhere inconspicuasly ..

 

i used to constantly blow boost gauge lines @ over 50lbs. boost wont drop, you will just have a small annoying leak. also if that line failed the wastegate would ever open and you would see more boost. this is not a reference line failure. most likely you just dont have the fuel. I dont care what anyone says, a bone stock truck with no fuel plate and a dicked with afc doesnt gain 900hp and smoke like a train (exaggeration).

do you have govoner springs? if your truck only revs to 2200 rpms there is only 2200rpms worth of gasses to spin the charger to X-psi. it would be obserd to expect 40 lbs on a stock truck that revs so low.

this could be a wastegate actuator problem, bleeding off to much drive pressure. test the actuator, adjust the linkage accordingly.

please unplug the wastegate. this should be done for test purposes only.

my big red flag however is the actual rpm's the engine is spinning to, this in ALL ways limits HP and the amount of boost you will see. sled pullers dont make 100psi going down the track @ 3k do they?