Boost Question

[spubar44]

At 45mph at 1400rpm's my boost is only 1.0psi this cannot be normal right?? I rarely see anything over 9.0psi when i get on it. What can be the problem? I was thinking fuel pump or restriction maybe. I have the 7.3l edge attitude, k&n air filter, straight pipe, banks turbo wheel, turbo already rebuilt, new CPS, New exhaust backpressure sensor, cleaned the tube for it too, disconnected the EBV, and the red waste gate line. tightened up all intercooler and connecting tubes. Oh and it seems that i only get about 13.7miles per gallon not towing anything. What is going on? I know this is supposed to have more power than this! This is my first diesel, but have been around motors all my life and have a good working knowledge. But this is killing me. Help me OH full of knowledge diesel owners! Fogot to add, i have replaced the fuel filter too. and when i get on it in level 5, i do not see any black smoke that everyone else sees, so that is why i am thinking it may be a fuel restriction.

[bigcountrysg]

Dang man, you got a problem there. I hope you get it fixed.

Originally Posted by spubar44

At 45mph at 1400rpm's my boost is only 1.0psi this cannot be normal right?? I rarely see anything over 9.0psi when i get on it. What can be the problem? I was thinking fuel pump or restriction maybe. I have the 7.3l edge attitude, k&n air filter, straight pipe, banks turbo wheel, turbo already rebuilt, new CPS, New exhaust backpressure sensor, cleaned the tube for it too, disconnected the EBV, and the red waste gate line. tightened up all intercooler and connecting tubes. Oh and it seems that i only get about 13.7miles per gallon not towing anything. What is going on? I know this is supposed to have more power than this! This is my first diesel, but have been around motors all my life and have a good working knowledge. But this is killing me. Help me OH full of knowledge diesel owners! Fogot to add, i have replaced the fuel filter too. and when i get on it in level 5, i do not see any black smoke that everyone else sees, so that is why i am thinking it may be a fuel restriction.

[spubar44]

Originally Posted by bigcountrysg

Dang man, you got a problem there. I hope you get it fixed.

OK here is something else i found. Idles fine, when in neutral i hold the rpm's at 2000 my boost is only .9 psi but it runs smooth, but when i hold the rpm's at 1200 it has a spot where the truck shakes like something is off balance and the truck idles up and down. Does that help anyone out there come up with an idea of what is wrong here? also is there supposed to be any boost at idle and if so how much?

[MrJohnWayne]

with not load on the motor it won't build boost. my truck in od at about 1400 rpms is only building about 1-2 psi also but if i'm cruising 70 at 2500 I run consistant 8psi. Does it take a while for the boost to build if you hammer on it or does it fairly quickly?

[straycat]

It also makes a difference where the boost gauge is taped into the boost pressure, If it is not Yd into the map line, it will not show the correct boost. You may also have a defective gauge. Just a couple things to consider.

Gord.

[spubar44]

Originally Posted by MrJohnWayne

with not load on the motor it won't build boost. my truck in od at about 1400 rpms is only building about 1-2 psi also but if i'm cruising 70 at 2500 I run consistant 8psi. Does it take a while for the boost to build if you hammer on it or does it fairly quickly?

yea the boost goes up quick when i get on it. I have the edge attitude display and it just plugs into the main wire harness so i think it is pretty good for correct boost display.

[tweener]

Without pulling a trailer or something.....the boost #'s you say, might be right, as it is just displaying what the map is seeing.....

I don't have a boost gauge or anything on mine, but I have a snap on scanner, and when i drove around with it plugged in...I saw like 3psi boost at 55 MPH.....if you floored it, it would show up to 10 or 11 psi .....When i hooked a trailer to it....it got as high as 15-16psi.....my turbo is in good shape....and is working correctly......the more load you apply to the engine, the more boost you will get....and as others said...where you measure it makes a difference.....if you measure it right after the turbo...you will read the highest pressure......the closer to the engine you get...the less pressure, as the air charge is cooled down, and becomes more dense, and losses pressure.........which is the point of an inter cooler.....so you can run even more boost.....