95RD

I checked the diaphragm and it is holding pressure (so no leak).  As far as the fuel, we have plenty of fuel going to the engine.  It is producing lots of smoke!  However the truck is still only producing only 10psi of boost. 
 

As far as the LDA. What pressure does it take to activate the fuel rail?  If the turbo is only producing 10 psi (max). Is the fuel rail even opening up to supply more fuel to the pump. 
 

Also, the truck is strong until it gets to the top gears.  Then it falls flat on its face. 
 

Does the fuel pump advance its timing as it gets to the top rpm rang? If so, how do you check to see if it is advancing. 

Update 

- Fuel is turned wide open. 
- Pryor is installed to watch EGT

However I am still having issues producing power.  The boost pressure is only getting to 12 psi max (usually stay in around 10 PSI). Having a hard time getting the truck over 60 miles an hour. Max I can get his 65 mph. Next step is to check the cooler for leaks. But I feel like I’m having turbo issues also.  Am I correct in saying that the turbo should be producing around 30 psi?

Pyro is on order!!  I will let you know what temps the egt's are at once I have it.  The fuel is turned up now and is definitely helping.  I am being very careful not to lung it any.  I am staying about 1400 rpm. 

1 hour ago, fjh said:

yup So the issue with the air fix is if the the diaphragm is burst inside you won't Know!  To check the diaphragm simply  suck  or blow on the hose if it won't hold a vacuum  or you can blow thru it the  diaphragm is toast! in evet  the diaphragm  still holds air , If you need to just take the edge off the sluggishness  remove the two screw cap at the rear and turn the screw in 1/4 turn at a time!  NOTE !This will still not repair the sluggishness if the diaphragm has a hole in it! proper fix is to replace the diaphragm!

Just sayin!

Yes!  That is the first think I am checking (and the supply hose from the intake) before I do anything to it.  

Thank you!  What about increasing the injectors.  Can you replace them with larger more powerful ones? 

Thank you!!  I will try that.  I will keep y’all updated. 

I have a 1995 RD 688 with and e7 350 all mechanical. I have heard for years how you can turn these engines up. To 400+ horsepower but I can’t find any information on how to do this. Does anyone have any information on how to do this. Do you change the injectors? Turn the fuel pump up? If so, how. 

Thank you for the information.  I was able to learn a lot from this.  I am having issues with "sluggishness" when loaded.  I am in the process checking my LDA per the video instruction.  I think I have a leak in the hose or in my LDA valve.  My question, is there a way to trick the LDA permanently?  To allow for full rack all the time.