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Thread: 4.8l to 5.3l engine swap now wont start

  1. #1
    Join Date
    Dec 2009
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    4.8l to 5.3l engine swap now wont start

    Just got done swapping 4.8l to 5.3l shaved the heads installed 2000 ls1 corvette cam and ls6 intake and now cant get truck to fire.
    I have tested for spark, fuel, injector pulse, and I have an rpm reading from crank sensor, also have taken care of all the vacuum lines for the intake swap. I am running the stock pcm from the 4.8l and i know that will affect how it runs but not cause a no start. Ran out of things to test wondering if anyone has any ideas

  2. #2
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    fuel pressure?

    ~ Forged engine of some type ~ Ball bearing turbo of an unconfirmed size ~ 4L8000 trans ~ Beefy fuel system ~

  3. #3
    Join Date
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    Quote Originally Posted by slinds View Post
    Just got done swapping 4.8l to 5.3l shaved the heads installed 2000 ls1 corvette cam and ls6 intake and now cant get truck to fire.
    I have tested for spark, fuel, injector pulse, and I have an rpm reading from crank sensor, also have taken care of all the vacuum lines for the intake swap. I am running the stock pcm from the 4.8l and i know that will affect how it runs but not cause a no start. Ran out of things to test wondering if anyone has any ideas

    how old are the injectors? if they been sitting for a long time or not used they could be clogged.
    Simple: 408 on steroids!
    single digits coming soon!

  4. #4
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    I have a lot of pressure but i cant test it because the test port is right behind the alternator now but it sprays hard when i press the valve. The injectors might be dumping fuel and flooding but it doesnt seem like i would have multiple injectors leaking. As far as them being clogged i pulled two of the plugs out and they were fuel soaked. next is to test each injector and pull all the spark plugs to see if they are all getting fouled.

  5. #5
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    Crank relearn cant be done till its running

  6. #6
    ff_jeff Guest
    try this maybe?
    Nelson Performance - Security Relearn for no start
    from Nelsonperformance.com

  7. #7
    Join Date
    Jul 2008
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    329
    If you have spark and fuel, look for something mechanical. Are you absolutely, positively, beyond a shadow of a doubt sure that you lined up the dots on the timing gears correctly? Since you shaved the heads, did you check the valvetrain geometry? Correct pushrod length, etc? First thing I would do is run a compression check on all cylinders. If the valvetrain geometry is off, you could be holding the valves open.

  8. #8
    ff_jeff Guest
    Quote Originally Posted by Madd Maxx View Post
    If you have spark and fuel, look for something mechanical. Are you absolutely, positively, beyond a shadow of a doubt sure that you lined up the dots on the timing gears correctly? Since you shaved the heads, did you check the valvetrain geometry? Correct pushrod length, etc? First thing I would do is run a compression check on all cylinders. If the valvetrain geometry is off, you could be holding the valves open.
    thats what quik said in his other thread on this issue. Could be the answer as well.

  9. #9
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    Found out that 4 out of 8 injectors were stuck closed. so $100 bucks later and I have all 8 injectors firing at 100%. The truck is running great just got the program done and everything is great now have the horsepower bug and wish i went with a bigger cam.

  10. #10
    Join Date
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    Quote Originally Posted by slinds View Post
    ...everything is great now have the horsepower bug and wish i went with a bigger cam.
    Go big or go home!

    2000 ECSB 6.0L
    TORQUER V2 CAM ● COMP 918's ● 7.4 HARDENED PUSHRODS ● K&N SERIES 77 CAI ● 80mm BBK ●PACESETTER LT HEADERS AND 3'' ORY ● SUPER 40 FLOW ● 3000 STALL ● 4.10s ● BUILT 80e ● VORTEC PERFORMANCE TUNE ● MSD 8.5mm PLUG WIRES● ELEC. CUTOUT ● UD & ALT PULLEYS ● FLEX-A-LITE E-FANS ● 22" CENTERLINE STINGRAY III's ● LUND FIBERGLASS TONNEAU ● 2" LEVELING SHACKLES ● 12K HID LOWS & FOGS ● LEDs ● DEBADGED ● WHITE-FACED ESCALADE GAUGES ● KICKER 450.1 ● 2-CVR 10's ● DS60's ● K693's

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