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Thread: non gm 4 cylinder gen 3 pcm startup issues

  1. #1
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    non gm 4 cylinder gen 3 pcm startup issues

    so this is off the wall but i have p59 green blue, dbw, ls pcm trying to control a non gm 4cyl. Ive wired it/have all sensors etc in place just like an ls1. i have known good coils/ injectors. i have good fuel pressure. vats is off. the only weird thing i have which i may change at some point is i have a 58x wheel with a lingenfelter box converting the crank trigger to 24x. im getting rpm signal, in fact its almost fired up a few times. the only thing i have noticed out of the ordinary is i can only see with a timing light 1 cylinder firing during cranking. is this normal? i believe its #4 (LS) cylinder thats only firing. i dont have a complete ls car nearby to check that kind of thing right now. ive tried timing/ve changes all over the place just to see if it makes a difference and i cant say for sure one way or another. ive tried MAF and SD and i guess SD got a little better result but never has it started. attached is my tune and my log of it trying to start. the only thing maybe working against me is my battery i have is dipping to 10.5 volts when im trying to start it so im charging it now. No codes that are showing up. any ideas?

  2. #2
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    Try this tune file

    Your RPM's look good for starting so it is getting a good trigger, if you are only getting one ignition signal, I'd try swapping the coils around to make sure your assumptions are true. Try this file with the maf unplugged and let me know if it starts. What size engine is this? Adjust your cranking ve and main ve until it fires up, it looks lean. I think you had some stuff under engine diagnostics that was putting it into reduced power mode which will just kill spark, I ran into this issue when I scaled my IFR and VE I disabled the stuff that causes it.

  3. #3
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    which things that I disabled would put it into reduced power mode? I tried a friends pcm that wasn't unlocked and all 4 coils were firing. so I unlocked that one too thinking my pcm was bad lol, maybe it is maybe it isn't at this point I dunno lol. so with the new pcm ive tweaked just ve/timing some trying to get it to start, its definitely trying but something is not right. timing light again is showing spark but it like cuts out every few revolutions so I think its not liking this lingenfelter box. I'm going to reengineer my reluctor wheel to be 24x to delete this box out of the equation, its not designed to do what I'm doing anyway I'm sure lol. its a saab v4 engine 1.7L, I literally just times the ve by .5 to see if that would work to start but I can always adjust that back. I should have the new wheel on next week so ill keep you posted and try that tune as well. thanks so far.

  4. #4
    Hold the pedal to the floor to put the ECU into clear flood mode and have your buddy spray starting fluid into the throttle body while you crank. If it wont start like that, you're not getting good spark

  5. #5
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    I didn't actually think it was a 1.7L v4, wow that is a crazy engine, off to youtube to look at videos of one.

    You weren't properly in SD mode, and it's Calc airmass P1514/p0068. Are you running a cam signal or no?

  6. #6
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    Quote Originally Posted by amello7580 View Post
    I didn't actually think it was a 1.7L v4, wow that is a crazy engine, off to youtube to look at videos of one.

    You weren't properly in SD mode, and it's Calc airmass P1514/p0068. Are you running a cam signal or no?
    so did you fix that in your tune posted? I thought I was in SD that would explain some things too lol. I am running a cam signal I modified somethings to give me a 1x cam signal, I honestly don't know how to verify if its working or not but I'm not getting any codes for it not working so I guess its fine? lol.
    Last edited by etizz; 05-17-2019 at 04:00 PM.

  7. #7
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    Quote Originally Posted by etizz View Post
    so did you fix that in your tune posted? I thought I was in SD that would explain some things too lol. I am running a cam signal I modified somethings to give me a 1x cam signal, I honestly don't know how to verify if its working or not but I'm not getting any codes for it not working so I guess its fine? lol.
    Yeah, I fixed it in the tune, you should be in SD now when the MAF is unplugged. It would probably take some time with it actually running for it to ensure the cam signal is fine other than if the was completely unplugged. I think it would still start with crank sensor only although not run as well but I've never tried running my engine with it disconnected.

  8. #8
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    ok quick update. i've gotten rid of my lingenfelter box and the 58x wheel. i now have a 24x reluctor and i am seeing rpm when cranking, i sitll need to fabricate the new crank sensor bracket but for some reason im not seeing spark with the timing light again, strange. once i get the crank sensor mounted good and wired ill diag some more. pretty strange unless its something in the tune thats disabling spark since 4 cylinders arent there. not sure. maybe ill have to actually use a 0411 and dbc for this to work i have no idea. let me know any ideas. thanks.

  9. #9
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    Ok I've fabbed my 24x reluctor and I'm only seeing spark on 1 cyl again , nothing I can do in the tune etc can bring it back . I'm lost as to why this keeps happening .any clue ?

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    just guessing here but i think your onto something with the 4 cylinders not being there... i wounder if you wired the other 4 coil trigger wires to the coils that are in use kind of making it like the old Nissan 4 cylinder motor that had 8 plugs on 4 cylinders Im not positive on this but maybe the computer is shutting down the signal because its not seeing the other 4 coils has to be something going on thats simple if you tried 2 computers with the same results

  11. #11
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    Just to ask the obvious but are you using a GM 24x wheel or an aftermarket wheel. GM has a weird staggered tooth wheel for both the 24x and 58x.. Does it look like the wheels pictured on this: https://www.onallcylinders.com/2018/...luctor-wheels/ site?

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    so my next plan is to go ahead and try a 0411 pcm, I'm picking one up from the junkyard today. everything was working and almost started even with the old wheel it just grenaded the pcms ability to give me spark apparently lol. new pcm and old wheel I had spark, and new reclutor with new pcm I had spark for like half a second but then it was limited to 1 cylinder again. my guess is after so many revolutions of not having 8 cylinders it freaks out and cant be remedied. so hopefully I have an answer tonight with a 0411.
    this was the old wheel

    then the new



  13. #13
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    Wow, super cool setup man, I hope the PCM works out!

  14. #14
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    So quick update , the car runs ! My random coil not firing was the crank sensor distance to the reluctor , some how had shifted away when I welded it up for good by a little. Once i figured that out I corrected it , and tried my green blue pcm again and it worked after some fuss but it's started a few times no problem and idled . Now i can move on to tune it further thank god lol .

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    heres a video of its second startup, 1st one was a surprise lol. the site cutoff the length of it I think , it was about a minute long of it idling the whole time at about 850 once it came down. https://imgur.com/PNhhKs6
    Last edited by etizz; 05-29-2019 at 08:11 AM.

  16. #16
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    F yeah dude, that's awesome, I had a feeling it was crank trigger related with it only firing that one coil. Gives me inspiration to do a 4g63/4l80e ranger

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    sweet awesome job!