I havent paid much attention to this but when I am pulling I will hit full boost around 3/4 throttle then the boost will drop a couple of lbs. Why would this happen? I would think it should stay at full boost as long as I have the pedal massed. EGT's are fine, too. This is happening around 2400 rpm so maybe there's some defueling going on?

 

Could be defueling, but most likely it is just the normal operation of the wastegate, especially if you have a boost elbow installed. The elbow will delay the opening of the wastegate but when it does open there will be a slight drop in boost pressure before things level out.

 

Engine is just consuming the boost.
It is also taking less fuel to sustain that speed vs accelerating to get there.

 

That makes sence except for that it happens while towing uphill. I would think since the engine is working so hard it should still be asking for as much fuel as possible because the pedal is mashed. The wastegate thing sounds like thats whats happening. Maybe if I totaly block the wastegate the boost will stay?

 

Mine is exactly the same. Only mine does it empty when I floor it. It hits 30lbs instantly for a second or two and then drops down to about 25lbs and slowly drops from there. I always thought it was the ez defueling but what Pourindiesel says makes sence.

Doug

 

If your EGT's are fine and you are not smoking much, why would you want more boost? Especially pulling a hill. Lower boost is better economy.

 

Its not that I want more boost. I'm just looking to make sure there isnt a problem. If others have the same thing happen then I guess evrything is OK. No my truck doesnt smoke at all. If it does then I cant see it, and I have tried to look, too. The EGT's are also very safe.

Its this web site...makes me paraniod.

 

But it can still de-fuel even with a box right? I know with almost all boxes but the drags they start to de-fuel around 2700. So the box can only play it's tricks to a point then the ecm will start to de-fuel?
Chase