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Had it in the shop and the mechanic said that it is the variable vains on the turbo. Why does it run better when it gets to normal running temp?
 

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Not much info. Do you have a monitor, what year, any codes? Load test batteries, check ficm, check fuel pressure. I suspect it's your ficm, not your turbo vanes.

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Truck surges when cold or under a load

Sorry about info. Its a 2004 F550 super duty. No monitor but I took it to a diesal mechanic ( ex ford dealership mechanic ). 38K on it, been on a scanner and showed no codes, please explain testing batteries, turns over fast. Idols OK. I will check FICM and fuel pressure. Just put new fuel filters on 3K ago. Stock engine but will do a bullet proof this winter. I will check with mechanic and see if he made those checks.
 

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This is exactly why you need a monitor.....http://www.powerstroke.org/forum/showthread.php?t=259257

Take your batteries out and have them load tested. unfortunately, starting fine to you(or any of us) does not mean they are ok, bad batteries are cause for many problems on the 6.0

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OK had everything checked out on a monitor and showed normal. Went to a new diesal shop and they found the same results. No codes and truck runs fine but the mechanic said that I am hearing the sound of the variable vain turbo through the the 4" straight pipe just installed. When it surges there is no change in RPM, Boost, or power, just the varying sound. Is this normal. When it reaches running temp it will not surge anymore. Missing something?
 

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OK had everything checked out on a monitor and showed normal. Went to a new diesal shop and they found the same results. No codes and truck runs fine but the mechanic said that I am hearing the sound of the variable vain turbo through the the 4" straight pipe just installed. When it surges there is no change in RPM, Boost, or power, just the varying sound. Is this normal. When it reaches running temp it will not surge anymore. Missing something?
I'm not sure about the 04 model, but later my strategies make the vanes flex during idle to help prevent them from seizing on the unison ring , over time. Have you considered cleaning the turbo. You may also remove the vgt solenoid and check for trash, I believe there is a screen in there.

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I have the exact same problem...keep this updated if you get it fixed, thanks!
 

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How old are your batteries and what are your numbers on the ficm check procedure? Sounds like ficm, but you just keep saying it's been checked out. Need some numbers bud.

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sticky,plugged up or failing EGR, can cause symptoms much like this. gunked up exhaust pressure sensor can do it too on some year rucks
 

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Thanks for the info. Checked batteries, all cells read 1275 to 1300 specific gravity, voltage 12.58, running 13.3. FICM voltage is 47.9 with key on, 48.5 at idle. Truck starts fine and idles fine. New egr valve 3K miles ago. Trying not to throw lots of money at this by doing trial and error. Truck meets all specs from Write Up: Monitoring the 6.0 PDS. I see I'm not the only one with this problem!
 

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Have you checked your EBP tube and sensor?
Iirc, the ebp is not used anymore on the 03-04 my.

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Yup....while I was reading about cleaning it, those of us with a vx7 or vx9 strategy, have the EBP disabled. No idea what MY that pertains to, but some dealers may have been updated to a newer strategy.
 

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I took it for a drive and watched the VGT as well as the boost. The VGT spec'd out fine, but the boost was all over the place. WOT and boost was 24.4, 22.5, 23.8, 22.0, 24.5, etc all within 4 or 5 seconds. While cruising at 70 on a flat HWY, it still moved around plus or minus 2lbs. I'm thinking a turbo rebuild? I guess I have to pull the down pipe to see if I have an oil swirl, right? Anything else I need to check before I get into that rebuild job?
 

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I took it for a drive and watched the VGT as well as the boost. The VGT spec'd out fine, but the boost was all over the place. WOT and boost was 24.4, 22.5, 23.8, 22.0, 24.5, etc all within 4 or 5 seconds. While cruising at 70 on a flat HWY, it still moved around plus or minus 2lbs. I'm thinking a turbo rebuild? I guess I have to pull the down pipe to see if I have an oil swirl, right? Anything else I need to check before I get into that rebuild job?
What about the vgt solenoid itself, don't they have a screen on them that can get damaged. It's a solenoid, it goes through millions of cycles. I don't know how to test them.

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What about the vgt solenoid itself, don't they have a screen on them that can get damaged. It's a solenoid, it goes through millions of cycles. I don't know how to test them.

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I'm not sure, I've never pulled one. I just assumed since the numbers weren't flopping all over the place that it was reading correctly.
 

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I'm not sure, I've never pulled one. I just assumed since the numbers weren't flopping all over the place that it was reading correctly.
So your saying your vgt numbers on the monitor are steady, and the boost is all over the place? I've never pulled one either, btw. No holes in the cac hoses huh?

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So your saying your vgt numbers on the monitor are steady, and the boost is all over the place?
Yes.
I've never pulled one either, btw. No holes in the cac hoses huh?

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Hot side has newer riffraff boots and the new metal OEM cold side pipe came with new boots also. Both purchases are well under a year old.
 

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i had similar issues but this fixed when i changed what custom tunes i was running. it seemed the tunes on the truck made it think it was hot engine all the time and it needed to run like a hot engine all the time.
 
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