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boost down 3psi

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Old May 3, 2011 | 11:34 PM
  #1  
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boost down 3psi

Just what title says, guys. About 2 weeks ago, rebult my turbo (comp wheel shaft broke), and knock on wood, trucks' run'n GREAT. I read a post from DBRUMMEND (aopologies if spelled wrong), and was mentioned to not exceed the 2k rpm, so i did, with no boost at all, for those 50+ miles. Onced i reached that plateau, i stepped up the game, but nothing at WOT, until i had a few more miles. Onced convinced, i drove ur like you should, i guess. Get'n on it, on freeway onramps..etc. Anyway, one instance, rip'n thru the gears, i noticed my boost was at 18-ish, i was STOKED, cuz before, best was 16/17-ish. This is now with a stock comp wheel. Now, i've noticed, that i cant top 14psi, no matter what i do.

So, i built a boost detector, didnt show anything, only thing i think of, is i installed the 470ohm resistor in the EBPV plug, so no soft code, and, prior to the turbo blowing out, i "capped" the EBP sensor (front of motor), but that was AWHILE ago. Not sure now, from reading other post, if my trucks in some type of defueling/low boost mode? Any thoughts' guys.

Also, i removed the 6637 and installed the K/N (cone), but didnt make any difference. Thinking, trying the, unplugging wastegate line, see what happens. Also, maybe the wastegate needs "tweeked", but throwing me off, since i did see the 18-ish psi.
 

Last edited by timmyboy76; May 3, 2011 at 11:44 PM. Reason: more info
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Old May 4, 2011 | 11:03 AM
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45 views???? Anyone, anyone.....throw me a bone, guys, i'm down to try/inspect any possibility.

If boost climbs with the red line disconnected, does that mean that the wastegate is "weak"?
 
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Old May 4, 2011 | 02:08 PM
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MR5x5
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From: Issaquah, WA
Since the leak detector showed things are tight, seems like you should concentrate on the turbine drive side, or maybe the gage.... Have you dbl-checked the baby's butt? Have you dbl-checked the connections/lines to your gage? Won't take much of a leak to realy effect the gage reading. Kind of doubting the wastegate spring theory - assuming you did not adjust it it should behave the same.

Couple thoughts... Good luck.
 
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Old May 5, 2011 | 04:32 PM
  #4  
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429 f-100
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From: oriental NC.
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timmy check out the mech waste gate from (diesel site) if i got to pull or rebuild my turbo this is what im gonna use no computer control all mech set to what you want and it wont release until boost hits adj. very cool mechanical piece. not sure if that is your problem but if is it should fix it for good. there are a couple people running it here. sorry i cant give you the link, but go to there site and check it out. i always like mech stuff over sensors and computers. wes
 
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Old May 5, 2011 | 07:19 PM
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MR and 429, appreciate the info and help. I'll take a gander at the mech wategate, fo sho.

I just dropped the wife at work, so i reached under the hood, and unplugged the wastegate vacuum, sure enough, i hit 21psi, so i letur off. However, i noticed, and even with the 14psi i'm get'n, it just seems that it doesnt have that "explosiveness" like it did, prior to the turbo grenading. Maybe its just me, but the "seat of the pants", feels more of just, "grabbing the gears". The "sound" is there, when turbo comes to life, but just doesnt seem to want to "bite", guess thats the feeling, i'm get'n?
 
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Old May 11, 2011 | 11:20 PM
  #6  
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UPDATE

Since its been "cooler" here, i noticed my psi back up to 16psi, however once it hits that, and i'm still on the go pedal, it'll fall to 14psi. Fuel pressure at idle is 69/70, wot 63/64psi, volts 14-14.5, oil pressure around 55psi. Not sure idf stock comp wheel, has anything to do with it. Tried my boost leak detector, but for some reason, gauge keeps bleeding off.
 
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