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Mark G Senior Member
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Don't know if the 392 will even run swapped back to the oem tb the the present tune.
Just swap it out with the OEM throttle body you're not going to hurt anything.
 

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Stu
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21,316 Posts
Discussion Starter · #22 ·
Think Keith said something to the effect of, it's tuned for the 90mm BBK throttle body. But, wont hurt to try it out... First, have to test out the OCP intake manifold pcv system I installed a few days ago. Will have to find a new place to install the intake air temp sensor.
 

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Mark G Senior Member
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1,971 Posts
If I were you I would try to get that air temperature sensor within 12 to 14 in from the throttle body that way you are safe it can pull timing if need be.
 

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Stu
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21,316 Posts
Discussion Starter · #24 · (Edited)
Looking to install iat sensor on the outlet side of the intercooler end tank before the w/m nozzle. Have to lengthen the harness or add a iat extension wiring harness.


50183
Automotive tire Automotive lighting Font Eyelash Auto part
 

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Mark G Senior Member
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1,971 Posts
Looking to install iat sensor on the outlet side of the intercooler end tank before the w/m nozzle. Have to lengthen the harness or add a iat extension wiring harness.


View attachment 50183 View attachment 50183
Looking to install iat sensor on the outlet side of the intercooler end tank before the w/m nozzle. Have to lengthen the harness or add a iat extension wiring harness.


View attachment 50183 View attachment 50183
OMG you don't need that just lengthen the two wires on the OEM harness.....
 

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Stu
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21,316 Posts
Discussion Starter · #28 · (Edited)
I'm Not going to mod the wiring harness Mark. Thanks for the input though. (y)
Will be installing the oem tb to see if it will run/runs better this week. It hunted/surged worse with the pcv system installed. Re-setting pcm and will take it for another quick test drive to verify the idle in gear hunting/surging has gotten worse. Had to take off the pcv system before to make it run better than it was. Never had these problems with my 03 KRC mild street boost tune. :mad:
 

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Mark G Senior Member
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1,971 Posts
Most likely the computer is reading the PCV setup as a vacuum leak... Stu give yourself a little more credit you're a much more talented person than you think! it's just two wires.
 

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Stu
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21,316 Posts
Discussion Starter · #32 ·
Tried raising and lowering the fuel pressure to try and see if the surging would stop or find the sweet spot. Didn't make any difference where the fuel pressure was at 42 or 65psi. Still hunted/surged at idle and at idle in gear. Had to try it.
Letting the truck cool off and will change back to the oem tb to see what happens.
 

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Stu
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21,316 Posts
Discussion Starter · #35 ·
Swapped back to the oem tb. It runs. That's a nice surprise to me. Seems to be better in some area's. So far it just has a very small hunt/surge in gear stopping/stopped with the a/c on. Not bad at all. But, hunts/surges when accelerating 1200 to 1900rpm-ish. The afr's jumping back and forth at those rpms.
Going to reset the running history. Will do some test drives (no boosting) and see it it goes stupid again.
 

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Mark G Senior Member
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1,971 Posts
Swapped back to the oem tb. It runs. That's a nice surprise to me. Seems to be better in some area's. So far it just has a very small hunt/surge in gear stopping/stopped with the a/c on. Not bad at all. But, hunts/surges when accelerating 1200 to 1900rpm-ish. The afr's jumping back and forth at those rpms.
Going to reset the running history. Will do some test drives (no boosting) and see it it goes stupid again.
I am not surprised at all that it is running. I think your problem still may be that the computer thinks it has a vacuum leak. What is your vacuum at an idle? And what is the difference between idle and cruising RPM? If you can put it in gear and hold the brake and bring up the RPM's so it is under load and see what your vacuum reads? Or you can just do the old carburetor cleaner trick just start spraying around and see if the idle surges.
 

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Stu
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21,316 Posts
Discussion Starter · #37 ·
Did the carb cleaner checks already. No vacuum leaks found. But, haven't done a recent pressure test on the intake manifold side.
 

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Stu
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21,316 Posts
Discussion Starter · #38 · (Edited)
1. Rpm hunts/surges at idle when stopping/stopped at a stop light?
2. Hunts/surges worse with a/c on?
3. Pcm makes adjustments to run better. It runs worse instead?
4. When driving 55+mph, let off of the throttle to slow down. The afr gauge shows a very rich condition. 12.2 to 10.0 afr.
* Problems # 1 & 2 have gone away with the a/c on or off. (y)
When accelerating with light throttle, it does hunt/surge 1000 to 2000rpm. It doesn't hunt/surge with heaver throttle. Believe that problem can be fixed with tuning now. (y)
  • It's good so far. The truck has been driving ok. Hasn't started to run stupid yet. Been running the same after each drive. Think the pcm was trying to adjust for the BBK throttle body problems..
  • The off throttle running rich when slowing down from 55+mph isn't as bad now. It still does it but, just not as bad.

Just completed a long test drive. Really pushed it this time. Did a some rolling into wot throttle test pulls at 6psi boost. Felt great for just 6psi boost. Strong mid to upper rpm. The afr was below 11.0 readings at wot and 6psi boost.
So glad I changed back to the rv/turbo street cam. The stage 4 turbo cam only made power at high rpm. Will see if it get's stupid again after that test drive...
 

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Stu
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21,316 Posts
Discussion Starter · #39 · (Edited)
Running and driving good still. Running well at wot boosting. Looks like it was the BBK throttle body that was causing the problems all this time. Even though I talked with the BBK technicians and they said nothing was wrong with it... :mad:
PS. Keith's tune is running strong at wot with only 6psi boost and a stock throttle body. Dam BBK throttle body... (n)(n)(n)
 

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Administrator
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The tune needs to be adjusted as soon as you decide on what fuel pressure you want to set it to and leave it alone at. Soon as you mess with fuel pressure you change injector size which changes AFR which changes short and long trims which changes your idle which changes your timing which makes it a shit show. Set it leave it tune it drive it.

as for the throttle body the older BBK units had a defect in them.Mine would hunt all over and at WOT would give me shut downs for over throttle blade travel. I spent a good week with scope and scanner and sent it all to BBK and they made me a new design (the current in use) and have had no issue since. I basically did the field research for them!
 
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