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Thread: need help on my first LS conversion,04 LQ9 in an 86 K5, no start

  1. #21
    Join Date
    Jul 2010
    Location
    Douglasville Ga
    Posts
    224
    If I understand correctly, early is 99-02 and late is 03+. Im still a little unclear about weather or not a blue green pcm can be used with dbc or if a red blue pcm can be used with dbw. Don't use the pinouts here as a view, but rather just for the cavity numbers, that way there will be no confusion about weather you are looking at the front or backside of the coonector.

  2. #22
    ok, installed new cam sensor and crank sensor. Have ignition all the way around now. Injectors are lighting Noid light. Still no crank. My programmer specified this pcm pn from an 03 with blue/green connector. I've been over the wiring and cannot find anything wrong but check me out anyway. Pin #'s in circles are in place, all others have been removed. I'm going by the pin #'s on the back of the aluminum connector housing. No. 1 is in the top LH corner. I see the way the connectors are keyed so one goes in opposite from the other and the pcm is marked blue and green. Gonna take fuel rails adn injectors off and clean next.bluec1b 001.jpgbluec1a 001.jpgP7170777.jpggreenc2b 001.jpggreenc2a 001.jpg
    Last edited by stevebbc; 07-18-2011 at 07:21 PM.
    Steve
    66 Chevelle, 454, 200r4, 12.9's, 86 K5 with 5.3

  3. #23
    Join Date
    Jul 2010
    Location
    Douglasville Ga
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    224
    I don't necessarily see anything wrong, although I am a little confused about some of your written in wires. Maybe a veteran will see the culprit.

    You may be way ahead of me here but don't take offense. There are many duplicate wires throughout the harness. Did you check continuity on the duplicates to make sure non of them were mixed up?

    At this point I bet its something you have "assumed" is right all along. Think about everything you have physically checked and what you have not. Physically check what you have not.

    Also at this point, its time to monitor an engine speed pid. That will be an excellent starting point. If the pcm sees engine rpm, and displays it on a scan tool, then there is no doubt that the pcm has everything it needs to start the engine.

    There has got to be some mix up with pcm pinning. I think the diagrams you are using are for a red blue pcm, although I am quite certain that all circuits required to run the engine are the same.

    Where are you located?

  4. #24
    Join Date
    Jan 2011
    Posts
    2
    hey steve are the shematics u have are from like gm work shop manual ? normally all sensors run on a 5 volt ref , but if u say u r shematic says 12v and on ur previous thread u said u had no voltage on the pwr for the crank sensor and then u did load test that circuit with a fog lamp bulb u could have high resistance, have u already ckd for fuel pressure or spark are all the plugs wet or only 4and 6 did u ck with noide light if injector signal ill try and get a shematic from work tomorrow and see if it says 12v like urs on crank sensor

  5. #25
    n-guerra, I replaced crank and cam sensor, now have 12v at sensors. Schematics are from links on this site and they are complete GM schematics for 03 Silverado 3500, in color even. I'm using this in conjunction with chart on LT1 Swap site on what wires to remove for a harness to run the motor only. Now could the positive 12v be knocked down to 5 by a -5v low ref out of the pcm? If so, then maybe u r on to something. Maybe this feature in the pcm is not working. I still have the 04 Escalade pcm with factory programming. Would it hurt anything to connect this one just to see if it would run it for a few seconds. I know the vats would turn it off.

    I have fire all the way round now and noid is lighting on all injectors. Took fuel rail and injectors off last nite and tapped them with 12v. All were spraying plenty of fuel that was still in the rails.

    Vortecyota - I'm in eastern N. Carolina. at least for now, if my wife doesn't kick me out
    Steve
    66 Chevelle, 454, 200r4, 12.9's, 86 K5 with 5.3

  6. #26
    Join Date
    Aug 2008
    Location
    North Texas
    Posts
    12,078
    Quote Originally Posted by n-guerra View Post
    hey steve iam new to this site: iam not a senior member but i know a bit about automotive u are not to have 12v at any sensor they run on a 5 volt reference voltage to ck for an open ohm out the wire it should read 2 ohms but if on two cylinder u are getting fuel fouled plugs i think ur issue would more likely be stuck open injectors just remove fuel rail make sure injectors are secured on fuel rail with thier locks cycle key dont crank and see which one leaks
    No, the CKP and the MAF for TWO are 12v.

    To the OP, those connector end views are with the terminal ends facing you, not looking at them where the wire go in as in the pics. Look closely at the aluminum body of the connectors and you'll see the numbers.

    I just now read this topic so forgive me but you're using a red and blue PCM like you should for this swap, right? At least it makes more sense to me for a DBC swap.

    If the plugs are wet, the injectors are doing something...most likely at the wrong time. A noid won't help injector timing issues. Does it have spark for sure?

  7. #27
    Ordered new pcm(411) and tune from a highly recommended tuner. Installed pcm, same problem, no start, occassional pop and misfire thru tb. Had spark and injectors were lighting noid light. I was told to do the "30 minute learn" procedure. Did the procedure and now have spark but injectors are not firing. I have a call into the tuner but haven't heard back yet. Anybody seen this before or know what's going on here?
    Steve
    66 Chevelle, 454, 200r4, 12.9's, 86 K5 with 5.3

  8. #28
    Join Date
    Jul 2010
    Location
    Douglasville Ga
    Posts
    224
    This is crazy. I wish you were close to me. I wanna see it. Never heard of the 30 min learn procedure. Injector timing is not critical to startup, ignition however, is. I know you know that, but. Gotta be cmp/ wiring, or coil wiring. Ckp is working because you do have spark and did have fuel. Move closer to me so I can figure it out. Lol

  9. #29
    Join Date
    Jul 2010
    Location
    Douglasville Ga
    Posts
    224
    On a serious note, if you get desperate enough, haul that dude down here to Atl and we will figure this out.

  10. #30
    Vortecyota, 30 min procedure is turn key to crank, then to on and let stay on 10 minutes, turn key to off, wait 5 seconds, then do this 2 more times. Sounds like something to do with VATS to me. Anyway it killed the injectors.

    I've been looking at my fuse block set up. I have one relay turned on by the keyswitch and it supplies power to the fuse block. Another relay running the fuel pump. When I'm cranking, the voltage at the fuse block drops from 12.5 to 10.5v. I get the same drop measuring straight off the battery. Seems like this should be sufficient to keep everything live while cranking. I get a good strong spark at the spark tester, you can hear it arcing.
    Steve
    66 Chevelle, 454, 200r4, 12.9's, 86 K5 with 5.3

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