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  1. E

    Random misfire at idle 454 vortec

    I will try and hook it up to my air compressor see what i get assuming the gauge is correct on compressor
  2. E

    Random misfire at idle 454 vortec

    Definitely the map which explains the resistors i found weeks back
  3. E

    Random misfire at idle 454 vortec

    It is technically 4 wire harness but has a 5th wire grounding the body of the 02. Some new things have been discovered if i unplug the map trucks runs damn near perfect obviously its staying closed loop but even before it missed then. It will never misfire with the map unplugged. The map...
  4. E

    Random misfire at idle 454 vortec

    Quick question ive just realized my pre 02 sensors bank 1 is a 5 wire bank 2 is 4. Which is correct it is a 97
  5. E

    Random misfire at idle 454 vortec

    I could not find any extensive wear too the guides. Seats and valves looked ok for a 240k mile motor nothing stood out there was some light carbon pitting i guess you could call it on all the exhaust valves. Also super careful cleaning up the heads and block for what it was worth.
  6. E

    Random misfire at idle 454 vortec

    Sorry for the delay ive been busy and ultimately dove into the heads over the last few weeks. What i found was a worn exhaust manifold surface at cylinder 1 and replaced the manifold. I know some may disagree with my approach to clean the valves but i lapped the valves and installed new mls...
  7. E

    Random misfire at idle 454 vortec

    Ive just performed testing again on 4 and 7 and was able too successfully do first try now that i fully understand the process. As far as your theory i dont believe that to be the case. *ive changed plug wires multiple times too factory firing order. *timing chain and sprockets were...
  8. E

    Random misfire at idle 454 vortec

    I was using the starter by jumping the relay and ive had the fuel pump relay removed while doing this at this point i am rotating by hand with both valve covers off trying too do this as correctly as possible
  9. E

    Random misfire at idle 454 vortec

    Dont be amazed lol i was holding the engine back with a crank shaft tool. And im also using a OTC leak tester
  10. E

    Random misfire at idle 454 vortec

    Im using a leakdown down gauge im spinning over until i hear compression out of my hose inserted into the spark plug hole and then rotating by hand too tdc on the balancer which has been correct it appears for 6 of the cylinders if i go past the mark i wont build pressure. I am putting 100...
  11. E

    Random misfire at idle 454 vortec

    Im watching the rocker arms and the tdc mark on the balancer. But does the timing mark actually matter on any cylinder other than number 1.
  12. E

    Random misfire at idle 454 vortec

    Im back with an update have had the rona and plumbing issues so i am back on the truck. Ive logged all the data i can and ive noticed something weird with number 7 and 4 any time i try too bring the cylinder up tdc the exhaust valves open befor i get there. Ive repeated both of those cylinders...
  13. E

    Random misfire at idle 454 vortec

    Im a little confused on what is acceptable for the leakdown. Any air coming from the intake and exhaust is bad? Or if your readings still fall within a 10% drop your good too go. Also the air observed from crankcase was at the oil fill tube.
  14. E

    Random misfire at idle 454 vortec

    Thank you very much for this breakdown. I will be doing the test over again over the next few days and i will report the results back.
  15. E

    Random misfire at idle 454 vortec

    Also i did briefly manage too get the truck too idle perfectly 10 seconds. While the truck was running i turned on injector balance test too cylinder 1. It was the smooth as glass. Im really starting too wonder if the driver for injector 1 is lagging. All the injector wiring ohms 0.2 ground...
  16. E

    Random misfire at idle 454 vortec

    Ok so i was initially not performing the leakdown correctly i was under the impression that you apply x amount of air and watch it hold without a constant air source. So that being said i repeated the process correctly and at 100 psi inlet side cylinder pressures were all at 90 psi or 88. Air...
  17. E

    Random misfire at idle 454 vortec

    Yes i have an actual tester. I did go too the exhaust felt nothing and nothing at throttle body. I didnt really give it much thought tonight just closed the shop up and called it a night
  18. E

    Random misfire at idle 454 vortec

    I was performing test alone so i used a whistle too get on compression stroke. Actually just cracked the air open at 50psi and it was coming out the oil fill tube fast as it was going in. I am redoing test tomarrow with 2nd hand too verify
  19. E

    Random misfire at idle 454 vortec

    And no nothing too cooling system or anywhere else i can hear
  20. E

    Random misfire at idle 454 vortec

    Not sure made 150 on compression test
  21. E

    Random misfire at idle 454 vortec

    All 8 new bosch
  22. E

    Random misfire at idle 454 vortec

    I just performed a leak down cylinder 1 tdc and i believe the worst has been found. Cylinder 1 100 percent loss instantly too crankcase. Bad rings
  23. E

    Random misfire at idle 454 vortec

    The schematic i had was wrong for injector 8 i did find it on the blue connector
  24. E

    Random misfire at idle 454 vortec

    Well definitely have zero signal wire too number 8 from ecm. And i cannot find it loose in the harness up by the relay box anywhere. I guess my next issue would where too get the pins too add the wire in. Im still confused because i did a injector balance test and they all bled down equally...
  25. E

    Random misfire at idle 454 vortec

    Update going while ohming out the injector harness from the ecm everything is solid except i made too injector 8 and there no wire too b5. And i could not find any on the b plug. So currently trying too probe all connectors too find it

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