Low boost/fuel problem?

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Mar 16, 2005 | 10:24 PM

#16

444dieselrod

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From: Braham MN

Quote:

Originally Posted by cookie88

That's not entirely correct sir. The pressure line that opens the wastegate is routed through the wastegate control solenoid, which is controlled by the PCM. When everything is hooked up and functioning the PCM will commad the wastegate start to open (STO) at 5 psi. That's how the PCM "limits" the turbo to 16-18 psi when there is generally enough stock fuel to support 20 or so with it disabled.

A buddy of mine recently bought an '02 and when I did the kwik filter on it I was looking at the wasegate setup and was wondering if the the pcm did have some control over the wastegate, now that I know it does. what happens when you unplug the sensor from the wastegate control solenoid???? will it set a code and go into limp mode???? if not do alot of people do that and unplug the red line from the diaphram???? just curious never attacked a new style beast before, still learning those.

Diesel Rod

Mar 17, 2005 | 12:05 AM

#17

wlihntr

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From: colorado

Quote:

Originally Posted by cookie88

That's not entirely correct sir. The pressure line that opens the wastegate is routed through the wastegate control solenoid, which is controlled by the PCM.

you are 100% correct sir. i forgot about that solenoid that the waste gate actuator line is connected to... i guess sometimes i get ahead of myself in an attempt to help out

Last edited by wlihntr; Mar 17, 2005 at 12:09 AM.

Mar 17, 2005 | 09:48 AM

#18

BadAss01F250

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I have the same problem you have Rodan....i have a 2001 F-250 with custom 4inch straight pipe exhaust (no cats or muffler), hypertech power programmer III, and K&N FIPK Gen 2 intake. from a standing start at WOT 2nd gear maxes out at 10-12psi but when i take my foot off the pedal, may gauge will "jump" of to 15 psi for less than a second. with an empty load, i will never pull more than 12psi whether im at a standing start or if im crusing at 70mph and i bury my foot into it. i still have my wastegate connected and while driving hard at WOT, EGT's dont go past 800 degrees. do you think that it could be an internal problem in the turbo???? im lost and want to get this problem fixed cuz i want to be making at least 20psi which i think i should be with those mods.

Mar 17, 2005 | 12:43 PM

#19

MRBASS

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Joined: Feb 2000

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From: LAKE FORK TEXAS

I would double check all the boots and the boost gauge line. My truck with just straight exhaust and the kwik filter will pull 24-25lbs of boost and exhaust temp wont go past 950. Maybe pull all the boots off and check for splits cracks or something, Got to be a problem somewhere for sure.

Mar 17, 2005 | 03:03 PM

#20

1997F-350

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From: SHELTON, WA

i just put my boost guage on today and i am the same as most of you as far as cruzing and highway wot 2800 rpms, 5th gear i am getting 22 psi. i think my truck is good. also for you auto guys it is probably hard for you to get it up there. good luck with your truck man.

97 psd 129k miles, 3to3 1/2 dp and no kitty......

Mar 17, 2005 | 07:33 PM

#21

cookie88

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From: Cabot, Arkansas

Quote:

Originally Posted by 444dieselrod

I don't think it will go into limp mode, but it does set a wastegate malfunction code when you unplug the solenoid. All that is necessary to disable it is to unplug the pressure line from the actuator and cap off the line, that way the PCM thinks everythng is still working. Until you hit 24 psi that is, then it will set an overbost code and defuel.

Quote:

Originally Posted by wlihntr

i guess sometimes i get ahead of myself in an attempt to help out

Indeed. I have the same problem sometimes. My big fat fingers don't type at the same speed as I think.

Mar 17, 2005 | 09:57 PM

#22

BadAss01F250

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this goes along with the post i posted earlier.....im not so sure that i have a problem with the boots on the boost gauge, they seem to be fine....to go along with my problem of low boost when im driving and hit the pedal to pass another car (chevy's especially) the power band pretty much levels out and i dont accelearate hard when im passing, i more or less slowly accelearate while passing. im completly stumped on this problem and its bothering the heck out of me. could it have anything to do with injectors???? i sure hope its not my turbo but for some reason in my gut i have a feeling that it is

. please help soon, i just want to get my baby running up to par. its just not running like it used too. thanks for all your help.

Mar 18, 2005 | 11:18 AM

#23

cookie88

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From: Cabot, Arkansas

I doubt it's the turbo or the injectors. Only getting 800 degrees under sustained WOT means you have a fuel delivery problem. Plugged filter, or fuel tank screen, or a failing fuel pump.

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Mar 18, 2005 | 12:04 PM

#24

1997F-350

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From: SHELTON, WA

why did you trade in your 95?????????

Last edited by 1997F-350; Mar 18, 2005 at 12:07 PM.

Mar 18, 2005 | 12:31 PM

#25

BadAss01F250

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Quote:

Originally Posted by cookie88

I doubt it's the turbo or the injectors. Only getting 800 degrees under sustained WOT means you have a fuel delivery problem. Plugged filter, or fuel tank screen, or a failing fuel pump.

my fuel filter isnt plugged, its brand new, changed it last time i changed my oil. how can i tell if my fuel pump is failing?

Mar 18, 2005 | 02:17 PM

#26

RodanAZ

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Quote:

Originally Posted by 1997F-350

why did you trade in your 95?????????

More room (super cab v. standard), higher gearing for highway (5sp w/ 4.10 v. 6sp), and generally a more comfortable ride. I'm amazed how much nicer the '00 is to drive. I loved the '95, it was a great truck, but I like the '00 better.

Mar 18, 2005 | 05:16 PM

#27

cookie88

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From: Cabot, Arkansas

Quote:

Originally Posted by BadAss01F250

my fuel filter isnt plugged, its brand new, changed it last time i changed my oil. how can i tell if my fuel pump is failing?

If it hasn't failed completely your really can't, other than measuring the output. Checking the pressure might give you an idea of what it's doing, but not an idea you can rely on.

The symptoms you posted sounded very much like the way my truck was running when the pump went out. I spent a week messing with the turbo, changing filters, blowing out lines, etc. I finally broke down and bought a pump as a last resort and it ended up being the problem.

If you need it, NAPA carries a Carter fuel systems Federal-Mogul pump #P74221. It's noisy and kinda pricey, but it'll move some fuel.