low fuel pressure

been running overtorqued stock headbolts for years. motor had 300K on it when I did it, with the original bolts. 18.5 timing, 40+psi. it works.
Theres a writeup here somewhere on doing it.
 
The big draw back to running the Cummins bolts is you don't get an ARP decal for the window dressing. That's something to think about.
 
i advanced the timing to 16 degrees and it made the truck run better and it feels stronger but im still having some issue with it. if im around 1500 rpm and i step on it the truck starts accelerating and is blowing black smoke and once the rpms get to about 1800 the smoke clears up and as soon as the smoke clears its like the truck is falling on its face, it just stops pulling.
 
Have you verified your afc is functioning properly? Make sure it has travel and no leaks in boost reference line.
 
Vincejax said:
Have you verified your afc is functioning properly? Make sure it has travel and no leaks in boost reference line.
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Afc is gutted. theres nothing in it to control fuel anymore. i gutted it because i thought it could be the cause for the issue and adjusted/checked it a bunch so i just took it apart but it didnt change anything. barley smokes more than when i had it together on the truck.
 
The truck is very drivable with the 0 plate and gutted afc. Easy to drive without it blowing black smoke. i like controlling the fuel with my right foot but with how people talk about the 0 plate and no afc i expected it would be hard to drive without smoke. maybe im just lighter on my foot than other people. driving around town its fine only when i get on it is when i have the feeling of it falling on its face.
 
Will a 0 plate slid all the way forward allow the rack to travel all the way to the rack plug? i dont have a mack rack plug and I dont know a whole lot about how everything works in the pump but does every plate limit fuel even the 0? im really just asking will there be more fuel running no plate compared to a 0 plate?
 
is it normal for the arm that hits the fuel plate to pull back when the engine is not running? when i had the afc off i was looking into the pump and moving the throttle (with out the truck running) and realized that the arm in the pump will move forward up to half throttle and anything past half throttle the arm retracts and i dont know if thats normal because like i said i dont know a whole lot about everything inside these pumps.
 
kyle830 said:
Will a 0 plate slid all the way forward allow the rack to travel all the way to the rack plug? i dont have a mack rack plug and I dont know a whole lot about how everything works in the pump but does every plate limit fuel even the 0? im really just asking will there be more fuel running no plate compared to a 0 plate?
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The only way you'll touch the rack plug is no fuel plate.

I still say no fuel plate and see how it acts.
 
jasonc said:
The only way you'll touch the rack plug is no fuel plate.

I still say no fuel plate and see how it acts.
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Took the fuel plate out. smokes a little more on the bottom end and clears up pretty good with more rpm and boost. the truck runs somewhat better but still feels like its falling off a little in 4th and 5th gear but not enough to complain about while the truck is empty. haven't towed my boat recently but thats when it was most noticeable. Think my actuator for the waste gate isnt working, the hx35 made 50 psi.. i tried adjusting the boost elbow but it didnt make much of a difference so i took out the allen screw on it so its open and it still goes to 45 psi. im not worried too much about it. planning on getting a new turbo anyway. But maybe its not a fueling problem? with the turbo making 50 psi to me that seems like the engine is getting enough fuel. and especially in 5th gear it feels like theres not much power at or over 2,000 rpms so governor springs? ill be getting new gov springs but could it just be the stock ones defueling that early? i thought it would atleast pull to 2,200
 
kyle830 said:
Took the fuel plate out. smokes a little more on the bottom end and clears up pretty good with more rpm and boost. the truck runs somewhat better but still feels like its falling off a little in 4th and 5th gear but not enough to complain about while the truck is empty. haven't towed my boat recently but thats when it was most noticeable. Think my actuator for the waste gate isnt working, the hx35 made 50 psi.. i tried adjusting the boost elbow but it didnt make much of a difference so i took out the allen screw on it so its open and it still goes to 45 psi. im not worried too much about it. planning on getting a new turbo anyway. But maybe its not a fueling problem? with the turbo making 50 psi to me that seems like the engine is getting enough fuel. and especially in 5th gear it feels like theres not much power at or over 2,000 rpms so governor springs? ill be getting new gov springs but could it just be the stock ones defueling that early? i thought it would atleast pull to 2,200
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How strong do you expect a stock 12v to be? Sounds like you are expecting a lot..
 
Vincejax said:
How strong do you expect a stock 12v to be? Sounds like you are expecting a lot..
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I have asked myself many times if im asking to much out of it and to a certain extent i believe i am. but at one point it had more power and ran better. one day it just started running strange and had less power. I remember the day it happened. i was driving up a hill that ive driven up hundreds of times and know how the truck feels going up it but one day while going up it the truck just fell on its face. i was about half throttle in 4th gear and the truck was driving fine and then all of a sudden it started running weird and lost some power. After that i only had power up to half throttle anything past half the engine would sound weird and wouldn't pull even on flat roads. replacing parts of the fuel system made an improvement and advancing the timing made some improvement but the truck has never ran like it used to.
 
After thinking about the day it started running weird it made me remember my idle speed also changed that day.. i didnt touch anything and the truck started idling at 800 rpm compared to 750 like it used to. Have i been looking at the wrong places for my issue this whole time? When i really should have checked the gov springs when i noticed the idle speed changed?
 
kyle830 said:
After thinking about the day it started running weird it made me remember my idle speed also changed that day.. i didnt touch anything and the truck started idling at 800 rpm compared to 750 like it used to. Have i been looking at the wrong places for my issue this whole time? When i really should have checked the gov springs when i noticed the idle speed changed?
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Governor springs effect idle. Imo you should definitely be running a set of 4k's. No reason not to. If your gov springs were loose that would lower your idle and rpm capability. The low fuel pressure even with the hotrod lift pump makes me wonder if you have wear on the cam lobe that drives the lift pump. But I don't see that changing your idle speed at all.
 
Vincejax said:
Governor springs effect idle. Imo you should definitely be running a set of 4k's. No reason not to. If your gov springs were loose that would lower your idle and rpm capability. The low fuel pressure even with the hotrod lift pump makes me wonder if you have wear on the cam lobe that drives the lift pump. But I don't see that changing your idle speed at all.
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i just ordered 4ks, 60lb valve springs, locks, retainers and head studs earlier today. im thinking the cam lobe might be worn because ive replaced pretty much everything i could think of that would affect my fuel pressure and the only thing i havnt checked is the cam lobe. im not worried about my idle speed increase because its pretty minor i just thought it could be a sign that somethings wrong with the governor springs.
 
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