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Discussion Starter #1
My truck seems to have really low boost. Averaging around 10 psi at 2500 rpm going 50 mph at a 6% incline. I checked for boost leaks with the homemade boost leak detector. Found nothing. All the IC boots are fine and not leaking. The intake boots are fine. The up pipes are fine. I even verified the boost gauge is accurate. So there's no leaks. Disconnected my waste gate vacuum line and it hit 15 psi. Any suggestions as to what I should do now? Maybe adjust the waste gate rod? Someone told me bad mapp sensor? I really don't know but I feel I should average around 20 to 25 psi.
 

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Garrett 38r.


Sent from my iPhone using Autoguide
 

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Boost depends on how you drive. If you are just cruising up the hill empty, your boost will be low. If you are accelerating up the hill or have a load and are giving it some fuel you will see about 18 psi on a stock truck. If the truck is modified on stock injectors you could hit about 30 psi.
 

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Discussion Starter #4
Boost depends on how you drive. If you are just cruising up the hill empty, your boost will be low. If you are accelerating up the hill or have a load and are giving it some fuel you will see about 18 psi on a stock truck. If the truck is modified on stock injectors you could hit about 30 psi.
This is at wide open throttle. It hits 10psi and then cant go anymore. Ive gunned it on flat ground and got around 10 psi. I had a loaded car trailer on a 4% incline and got 12psi. Something is very wrong here.
 

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Discussion Starter #5
Any suggestions fellow powerstroke owners?
 

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Wastegate could be weak.
 

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same boat man. I even swapped turbos, and still 10psi with redline hooked, 15-16psi w/out it hooked.

I did the 10k mod for ****s, and hit 22psi with redline unhooked. So i bought an ICP sensor and still the same low numbers. Think'n of try'n MAP sensor or possibly a weak hpop..dunno.

A mamber found a boost leak at where the plenums bolt to heads. Maybe try that, soap it up and pressure system again.
 

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Discussion Starter #8
I have recently rebuilt the turbo. And replaced the ICP sensor. Still only peaking at 10 psi. I will re pressurize the system and check for leaks again tomorrow. I checked my waste gate operation today with a compressed air and a gauge. It begins to move the rod at 5 psi then more at 10 psi its in its fully opened point at 25 psi. So shouldn't that mean I should be peaking at 25 psi?
 

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i'll be the guinea pig to this man. Since already tried the ICP, why stop now, right. Gonna pull the trigger on the MAP, and go from there. I'll update when available. That dont work, then the IPR, if not again, HPOP. Trucks 13yrs old, has the original sensors/units in now, so i think i got my use outta them.
 

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Discussion Starter #10
i'll be the guinea pig to this man. Since already tried the ICP, why stop now, right. Gonna pull the trigger on the MAP, and go from there. I'll update when available. That dont work, then the IPR, if not again, HPOP. Trucks 13yrs old, has the original sensors/units in now, so i think i got my use outta them.
Sounds great! Keep me informed. I re-pressurized my system with soapy water and found no leaks again. There is an extremely small leak on my up pipe. That shouldn't drop boost so much will it? I even disconnected my air box and let it breath free thinking maybe its just air restricted. No change is boost psi.
 

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Discussion Starter #11
So I just used an emissions smoke machine to pressurize and re check for leaks. Again there are no boost leaks. I re adjusted my waste gate rod. I used a scan tool and found no codes. I did every possible ford scan tool test and everything passed. I'm still only getting 10 to 12 psi of boost?! What is going on here?!
 

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Fuel pressure, ICP, MAP reading, EBP reading. They could all cause something weird.
 

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Discussion Starter #13 (Edited)
Fuel pressure, ICP, MAP reading, EBP reading. They could all cause something weird.
I verified I have 70psi in the fuel bowl. The EBP sensor and line are brand new. As for ICP, MAP I am clueless. What exactly do they do and how do I test them? I'm still learning all this as I go.
 

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I verified I have 70psi in the fuel bowl. The EBP sensor and line are brand new. As for ICP, MAP I am clueless. What exactly do they do and how do I test them? I'm still learning all this as I go.
70 psi under wot?
Icp is the pressure sensor for the high pressure oil.
Map is your oem boost sensor. You need something that can read the data from them

I made my Samsung SGH-I997 send this.
 

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Discussion Starter #15
70 psi under wot?
Icp is the pressure sensor for the high pressure oil.
Map is your oem boost sensor. You need something that can read the data from them

I made my Samsung SGH-I997 send this.
70 psi at the fuel bowl. I have 480 psi in idle and 2800 at wot from the hpop. The map reads 14 psi at idle. I did a test of my ICP. I was told to unplug it and my rpm should default to 725 rpm? I did this and got 680 rpm should I be concerned about this? And also when I unplugged the ICP it was drenched in oil?? Does the ICP have anything to do with how much boost i make?
 

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Ding ding ding we have a winner! Replace that ICP, the oil leaking through it will cause it too short or read low and cause low pressure reading, replace it and clean the connector real good or replace the pigtail if its in bad shape, also what was previously stated you need to check fuel pressure at wide open throttle. Sounds like your on the right track though.
 

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Discussion Starter #17
So the ICP controls injector pressure from the HPOP? If I have an accurate reading at WOT doesn't it mean the ICP works even though its filled with oil?
 

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Discussion Starter #18
Well I ordered the ICP today it should be here tuesday. I cleaned the oil out of the old one and packed it with di-electric grease. I actually got a steady 15 psi under WOT up a steep hill. Im not sure if me doing that made a difference.
 

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The pressure reading through a scan tool is only what the icp sensor thinks it sees, not the actual pressure.
The actual pressure will influence the amount of fuel which will influence boost pressure.
 

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Discussion Starter #20
I put the new ICP in and no difference in boost pressure.
 
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