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LS3 crate motor will not start

Discussion in 'General' started by 52Chev, Jan 6, 2015.

  1. ari666

    ari666 250,000 hits

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  2. 07GTS

    07GTS Well-Known Member

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    if its got fuel pressure then just need to make sure injectors are pulsing if yes then its getting fuel, then check spark and if its getting spark also then something is not right should be firing or at least trying too, check the inj like ari666 mentioned with the led then u have a visual u can see, alot of multimeters may not respond fast enough to see the ms pulse of the injector
     
  3. 52Chev

    52Chev New Member

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    E67 ECU, 60 psi at the rail waiting, 160 rpm on crank, but no pulse at injectors or spark? Thanks again for your help so far.
     
  4. ari666

    ari666 250,000 hits

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    good solid voltage to the ecu while cranking?

    dunno if your ignition key is the same as my 66' but "acc" switches off when cranking, so make sure youre not using that to power the ecu, coils or injectors. on my impala the "acc" is a thick brown wire so its misleading. the one i used i think was pink and was very thin, i ended up hooking up a 60A relay and a 60A fuse to the pink wire to drive my ecu, otherwise it wouldve burned out that wire in no time.

    acc is only used for the ciggie lighter, wipers, radio etc and it powers off when the starter is kicking so the acc dont drain watts.
     
  5. 52Chev

    52Chev New Member

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    Solid 11,8v during crank. Yes my acc drop out during crank but there is no drop in voltage to the ecm. It has to be in the ecm I think ari666?
     
  6. ari666

    ari666 250,000 hits

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    if the PCM is getting RPM then i cant see why it isnt outputting that RPM to the coils. have you done the injector test? are the sparkplugs wet when you pull them out?

    is this a deadhead fuel system or a return?

    far out i dunno man. im guessing the PCM came with the engine, so all the settings should be already done... would have to be wiring.
     
  7. 52Chev

    52Chev New Member

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    I get the rpm indication from the odb plug so you would think that is thru the ecu. Dead head fuel system. Noid test failed as there was no light. Plugs dry. I am at a loss as well ari666.
     
  8. ari666

    ari666 250,000 hits

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  9. ari666

    ari666 250,000 hits

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  10. ari666

    ari666 250,000 hits

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    see diagram:
    [​IMG]

    yo can see the + supply isnt the same as the ecu, so even if the ecu has a nice 11.8, if youve hooked up the coils to acc, theyll switch off while you crank. so all the sensors will still function cos' they get +5v off the ecu, theyll send a - trigger to the coils and injectors, but if the + isnt there, then nothing will happen.


    without hooking it up to hp_tuners to check sensor operation, im totally stumped.

    160rpm while cranking is about right, so your home and trigger sensors are both workiing and reporting and the starter is turning it fast enough to fire.
    voltage at the ecu is 11.8V so the ecu has plenty of power to drive all the +5v triggers
    60psi at the rail is PLENTY
    it MUST be a voltage issue.

    unless the PCM just isnt setup for something on your engine. whether the input parameters for "crank low res" is wrong, or VATS is somehow fragging it. but if the ecu came with the engine, then the odds of that are very very low.
     
  11. ari666

    ari666 250,000 hits

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  12. 52Chev

    52Chev New Member

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    Yes ari666. I have dakota digital gauges and they have an engine light in them. This is what is shitting me, I have no codes so I am just triple checking the same things.
     
  13. ari666

    ari666 250,000 hits

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  14. 52Chev

    52Chev New Member

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    Ari666, do you use hp tuner? I might have to do a course and learn the insides of this computer.
     
  15. ari666

    ari666 250,000 hits

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  16. 07GTS

    07GTS Well-Known Member

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    how do u find the RTT is there much u can change whilst on the go..? i usually just go for a drive and try to hit a curtain range/load and then head back and then look at log and adjust from there which can take up a afternoon quite easily, but yea the second i seen my tuner showing me the program i had to get it i just love all that tuning side and once u get your head around it its gold...
     
  17. ari666

    ari666 250,000 hits

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    now that the tune is pretty much complete, then running logs is pretty much the same as RTT, since you need to copy/paste/flash the new VE tables anyway with RTT, but at the start when i was trying to get a VT commodore tune to work on a 454, then yeah it was cruicial, the immediate changes to vacuum, rpm etc were really helpful to see what changes had what affect, and you witnessed it happening right away. not only that, it was much easier to ignore events that you know would skew your data, lets just say you were idle tuning and you knocked off a vac hose which sent a spike, you could look back at the figures youre about to load, look back at the historgrams and chose to ignore the data of that section, load the new data and watch what happens, without have to stop, turn the engine off, flash, restart, then watch again.

    the actual functionality of it could be improved quite a lot. idle tables and IAC are based off a different RTT file to VE tables, so you need to head back to your base tune file and flash the different RTT file so you can use it, which is a bit **** if you want to change 2 seperate things at once, like: get idle right while also changing VE tables. plus there have been a few times ive spent 20 or so mins driving and making changes, only to get back REALLY happy with the progress. shut the laptop and switch off the engine only to remember that i needed to copy/paste the tables i had just been editing... fkn sucks man.

    but is it worth 2 credits? ... probably not at this stage, but if i had a stock tune and i was fresh installing a decent cam, id prolly front the extra coin for it again, yeah.
     
  18. 07GTS

    07GTS Well-Known Member

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    looks like under some circumstances it would be great and then some would be same as normal, yea i hate it when u loose your work ive had a couple logs lost when i go to look at them and i press record instead of play and it starts fresh and then i realize it wasnt saved yet either...
     

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