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Low vacuum on rebuilt

Tiny
LARRY YODER
  • MEMBER
  • 2007 CHEVROLET SILVERADO
  • 5.3L
  • V8
  • 4WD
  • AUTOMATIC
  • 25 MILES
It had 249000 miles on it the AFM failed and wasted the cam. I did a total rebuild on the engine. Did a mechanical delete on the AFM installed engine and it started up very easy has 40 psi oil pressure runs smooth had it tuned, but it has no power and I only have fifteen inches of manifold vacuum and the tuner said the fuel trims are thirty percent lean. I did a compression test and I have 195 and 200 psi on all eight cylinders. I replaced the intake gaskets did not help pulled timing cover crank timing mark at twelve cam gear mark at six no one piston at TDC. Any ideas?
Thank you
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Thursday, June 15th, 2017 AT 5:11 PM

4 Replies

Tiny
STEVE W.
  • MECHANIC
  • 13,476 POSTS
What method did you use to delete the AFM? Have you reprogrammed the ECM to a non AFM configuration?
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Thursday, June 15th, 2017 AT 10:21 PM
Tiny
LARRY YODER
  • MEMBER
  • 3 POSTS
I did not do the programming I had it done he uploaded the program from my ECM and he deleted the four ECM codes for the AFM solenoids.
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Friday, June 16th, 2017 AT 3:22 AM
Tiny
LARRY YODER
  • MEMBER
  • 3 POSTS
AFM solenoids I did a full mechanical delete. New cam lifters non AFM valley plate and plugged the oil ports under the valley plate.
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Friday, June 16th, 2017 AT 3:30 AM
Tiny
STEVE W.
  • MECHANIC
  • 13,476 POSTS
Do you know which timing map is in the programming, It's been a while since I did a defeat but I seem to recall there is a different ignition timing map.
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Sunday, June 18th, 2017 AT 4:27 AM

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