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Thread: LS1 Swap cranks, but no fuel and no spark

  1. #21
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    Video doesn't work.
    With the key on try checking voltage between the pink wire and the black wire, then resistance from that black wire to engine ground.
    THEN Check voltage between the PINK wire and BLACK wire for the main coil pack plug. Then check that BLACK wire to engine ground. Do this for both.
    THEN check voltage at the PINK wire to engine ground on every injector. Yes, every injector is powered up with the key on and pulsed to ground by the pcm.
    Check the cam position sensor PINK and BLACK.
    While you're at it check to be sure the CAM POSITION SENSOR is not swapped with the CRANK SENSOR.

    It's a swap vehicle, the harness needs many 12 volt key on wires connected to the right place and many grounds connected.
    And two constant battery power wires.

    Can you check them?

  2. #22
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    Quote Originally Posted by Jason B View Post
    Video doesn't work.
    Copy and paste the link and it should work.

    With the key on try checking voltage between the pink wire and the black wire, then resistance from that black wire to engine ground.
    Which pink and black wires?

    [QUOTE]

    THEN Check voltage between the PINK wire and BLACK wire for the main coil pack plug. Then check that BLACK wire to engine ground. Do this for both.
    THEN check voltage at the PINK wire to engine ground on every injector. Yes, every injector is powered up with the key on and pulsed to ground by the pcm.
    Check the cam position sensor PINK and BLACK.

    While you're at it check to be sure the CAM POSITION SENSOR is not swapped with the CRANK SENSOR.
    Do they use the same plug?

    It's a swap vehicle, the harness needs many 12 volt key on wires connected to the right place and many grounds connected.
    And two constant battery power wires.

    Can you check them?
    I checked all of the power and grounds on the "blue" harness. i'll check the other harness tomorrow.

  3. #23
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    [QUOTE=circuiticon;493065]Copy and paste the link and it should work.



    Which pink and black wires?


    THEN Check voltage between the PINK wire and BLACK wire for the main coil pack plug. Then check that BLACK wire to engine ground. Do this for both.
    THEN check voltage at the PINK wire to engine ground on every injector. Yes, every injector is powered up with the key on and pulsed to ground by the pcm.
    Check the cam position sensor PINK and BLACK.



    Do they use the same plug?



    I checked all of the power and grounds on the "blue" harness. i'll check the other harness tomorrow.
    They use the same plug, if they didn't I wouldn't have said that.

    Which pink and black wires? The ones AT EVERY SENSOR CONNECTOR, AND PINK TO ENGINE GROUND ON EVERY INJECTOR. UNPLUG THE CONNECTOR AND TEST THE WIRES THERE. DID I NOT MENTION SPECIFICALLY WHAT WIRES TO CHECK?

    YOU HAVE AN INJECTOR PULSE----THATS THE PCM PULSING GROUND, IT DOESN'T KNOW IF IT HAS 12 VOLTS OR NOT. YOU HAVE NO SPARK BUT A TACH SIGNAL---GREAT, THE PCM IS PUTTING OUT THE SIGNAL BUT MAYBE THERES NO POWER TO THE COILS.

  4. #24
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    Sorry, it was late so I just skimmed over it, and the way you wrote it was confusing since the first thing you asked me to do was check a set of wires without specifying which wires until later.

    I did check a lot of the grounds last night, and they had little resistance. I'll do more today. I also tested continuity between the ECU and one of the injectors and it checked out.

    I doubt the cam and crank plugs are mixed up since I'm getting around 140rpm, which is in line with what is expected from cranking. I'll double check anyway, though.

    I think you're onto something though, if the ECU is sending out the switched ground and the injectors aren't firing, perhaps they're just not getting power.

  5. #25
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    Quote Originally Posted by circuiticon View Post
    Sorry, it was late so I just skimmed over it, and the way you wrote it was confusing since the first thing you asked me to do was check a set of wires without specifying which wires until later.

    I did check a lot of the grounds last night, and they had little resistance. I'll do more today. I also tested continuity between the ECU and one of the injectors and it checked out.

    I doubt the cam and crank plugs are mixed up since I'm getting around 140rpm, which is in line with what is expected from cranking. I'll double check anyway, though.

    I think you're onto something though, if the ECU is sending out the switched ground and the injectors aren't firing, perhaps they're just not getting power.
    I'm not that good at this, sorry about that. If it was in person it would be easier you know.

    I did a swap earlier this year and did the harness work myself, when I started it the MAF had no power and the cam position sensor didn't work right. Found out the MAF was just wired to a dead wire that was supposed to be key on power.
    The cam sensor had two wires swapped because it's a Gen IV block with a front mounted sensor (timing cover) my cam sensor plug fit perfect but the two outer wires are swapped. I found this out when I found there is an adapter plug that has the wires swapped already.

    But I went through real quick and checked at the key on power wires for 12 volts. I'm not sure how your swap wiring is, I know some like to wire all the key on power wires to one or two fuses. This way when you lose a connection a lot goes dead.
    I wired mine to the factory locations so most of my stuff is labeled same as it was factory and I can lose a circuit and only one or two injectors go dead, etc.

    Sounds like you have a good idea of what to do, hope the next post is of it running.

    PS your youtube link takes me to MY youtube edit page, it might only work for you because it must take you to your edit page or something. Not even going to try to trouble shoot that.

  6. #26
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    I updated the youtube link earlier today, so if you refresh you should be able to see it:

    http://youtu.be/I1oNBOKXkqo

    But alas, I have good news. Just as you suspected, the coils and injectors did not have power. There's a black 8 pin connector (which only actually has 6 wires in it) on the driver's side of the engine. There is a red wire in that connector which supplies power to the injectors and coils. So we powered that red wire, and the noid light and the spark testers both lit up while cranking. We switched on the fuel pump and she fired right up!

    It doesn't idle super well, but i suspect that may have to do with my larger throttle body (which also lacks the small hole in the throttle plate like the OEM TB has).

    Any advice on what's involved with tuning a larger TB? It's one of these 92mm throttle bodies:

    mQ3EzWsVr9aUvjVH7mxvB5w.jpg

    Also, if I convert this to speed density, are there off the shelf maps to make this work, or will the stock tables work fine? I'd rather not have to tune it from scratch.

  7. #27
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    I I changed it to run off of the GM 1 bar MAP and it idles a lot better.