hi all im new to the site and pretty new to diesels. i have a 97 12 valve cummins i recently took the fuel plate out, replaced the cupped washer in the diapham blocked of the wastegate, and installed guages. i have it tuned now to where its running ok but it starts harder than when the plate was in and i max out at 17 or 18 pounds of boost. it should be making well over 20 with the wastegate blocked off right? and also it only makes a little puff of dark grey, black smoke right when i punch it. i moved the smoke screw in all the way and it didnt change anything. is it possible i put something back together wrong and some how its still running. thanks for the help guys. also not shure if this is posted in the right place i just wanted to get answers as soon as possible

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no ideas out there could it be that i didnt shave down the afc foot? would that cause me to get such a small amount of boost? also i forgot to add as it sits right now it isnt making much more power than it did stock.

 

did you remember to slide the housing on the pump towards the front of the motor before you tightened the 4 screws down?

 

starwheel adjusted? i only got around 20psi with the same mods...i didnt get 35+ till i installed my injectors and gsk

 

just take the finger out

 

No do not just take the foot out, that hack tuning and will only gain you a smokey mess... There is plenty of people with well over 700hp with the AFC still in place. A gov spring kit and a nice set of injectors will get you what your looking for but you should have seen and felt a great improvment with the little mods you have done already

 

you can control it all with your foot thats one of the best things about mechanical pumps

 

its hard to understand these problems if we dont know what your truck was doing before. max boost, smoke levels bla bla bla.

the star wheel should be pretty close to the front of the pump when its all tuned up. i wouldnt think 25 clicks from stock is the right place to be?? did you check the AFC with air when you adjusted it?

 

yes i slid the housing foward and screwed the smoke screw back to stock and it all feels the same. just making sure the housing only moves like a 1/4 inch right.

when it was all stock it didnt smoke at all after it was warm max egts was 950 give or take, boost would climb to 12 and it was slower then a geo metro. also wouldnt climb a hill to save its life.

I got it to where it will hit about 950 egt again but thats maxed. it has been pretty cold here i dont know how much that would effect it. and from what i can tell mid range power from like 1250 rpm to 1800 rpm is way better than it used to be but it dies off right around 1850 and shifts at 2100 except in 3rd it whines out to about 2650 and that is the only time it hits 17 psi.

 

Sounds like his rack is stuck. Ok if I remember right there's a little shaft that is horizontal inside the cover that looks as if it runs under the injection lines work that with your finger and seeif it budges. Either that or your fuel shut off isn't lifting up all the way. Hope that helps

 

That was it the fuel shut off wasnt opening the whole way. Thank you so much for the input 5.9sledhead. I took it out for a test drive with it opened up and wow it was like a rocket. I couldnt focus souly on 1 gauge and the road and smoke but I was making around 30psi boost and hit about 1250egt before i had to back off.