Results 1 to 9 of 9

Thread: e38 l92 swap won't start I think due to Powertrain relay coil control not +12

  1. #1
    Junior Member
    Join Date
    Mar 2010
    Posts
    46

    Default e38 l92 swap won't start I think due to Powertrain relay coil control not +12

    I have an off-road buggy with an l92 engine in it. I was previously running a speed density Mast M90 setup but I am switching to a GM e38 ECM and the wiring harness that came with the engine.

    I have an LS3 MAF in my aluminum intake (using the GMPP bung)
    I am using the LS3 throttle pedal and throttle body the mast setup came with (and the pedal controls the TB just fine wiring the pedal straight to the e38)

    I have disabled the VATS in efi live as well as the starter relay diagnostic
    I setup the fuel pump green-white stripe wire to my fuel pump relay

    I wasn't using the powertrain relay coil control wire (pin 59 yellow or white-black stripped on other e38 harnesses apparently) but I'm wondering if that has to be outputing ignition voltage (+12) or the ecm will prevent the engine from starting? I am getting .01v right now on that wire.

    I don't get any codes from the ecm once I get everything all setup. all knock, cam,crank sensors are hooked up and EFI live scanning can detect the RPM coming from the engine when I am cranking it.

    when I crank the engine, the 8 ignition coil circuit pids say they are on. but the 8 fuel injector circuit status pids never go to on. i have +12 to all 8 pink or pink-black wires for the injector harnesses.

    it seems like the ecm is preventing the fuel injection from happening because it either things the engine isn't "running" or due to VATS etc.

    I am now going to rewire the injector pink wires to go through a relay I have setup to the powertrain relay coil control wire to see if somehow the ECM detects something across the relay (like it seems to do on the fuel pump) to decide the engine can run.

    Does anyone have ideas of what to check for in EFI live as to why the ECM isn't commanding the fuel injectors to come on?

    Thank You in advance!

  2. #2
    Lifetime Member GMPX's Avatar
    Join Date
    Apr 2003
    Posts
    13,148

    Default

    Try putting a relay on the starter output as well (one side to the ECM, the other to ground) or set G1220 to "Not Used".
    I no longer monitor the forum, please either post your question or create a support ticket.

  3. #3
    Junior Member
    Join Date
    Mar 2010
    Posts
    46

    Default

    I've been reading over the thread here:
    http://forum.efilive.com/showthread....no-start/page8

    so after posting this thread, I put a relay with pin 86 to the pin 52 starter relay wire and grounded pin 85 of the relay. I didn't hook up pin 30 or 87 on the relay to anything.

    That did not change anything, I still have no fuel injectors coming to an "on" state during scanning but the coils go to on during cranking/scanning.

    One thing I don't follow in that thread is that several people say to do a "full flash" or apply a VATS patch? I think you can only full flash via the EFIlive 8.0 software so I am going to try that next. but is that what people mean in this context? also what is the VATS patch? is that a patch to the EFIlive software to let it disable vats or is it a "patch" to the ECM. I am at the latest version of 7.5 tune 7.5.6 build 139 as well as efi live 8.2.1 build 160.

    in efi live 8 the security section isn't implemented yet. in 7.5.6 I don't see a vats patch in the security dialog, just a vats relink and ignition cycles button. I couldn't find "vats" as a search string in any of the help pdfs or tutorials either but I'm apparently missing something.

    I guess I'll do a full flash in v8.2.1 now. I've attached my .tun file as well where I think I have VATS and the starter relay diagnostic disabled. I thought that would prevent the ecm from looking at pin 52 before starting but apparently not?

    Thank You!

  4. #4
    Junior Member
    Join Date
    Mar 2010
    Posts
    46

    Default

    Apparently my memory is outdated on the 7.5.6 software. I just downloaded 7.5.7 build 170 to see if there are any more options or newer tutorials and see if the scan tool picks up on anything. I was wondering why the e38 DVT was only giving the option of 7 injectors to test

    Also just to provide more information I am "starting" the engine by using a push button starter I've had on my dash right to the large purple wire that goes to the starter. Its running the starter just fine but it makes me wonder if I'm missing a wire that tells the ECM its being started. several threads discuss this but I don't see a confirmed answer. when the engine is cranking the RPMs come up and I see that the ignition coils go on so my thought is the ECM "knows" the engine is trying to start based on that. but for whatever reason it won't turn the injectors on.

  5. #5
    Junior Member
    Join Date
    Mar 2010
    Posts
    46

    Default

    I double checked and the G1220 you mentioned is the same area as the starter relay diagnostic setting and i have that set as well as G1220 as shown below
    Click image for larger version. 

Name:	disablestarterrelaydiagnostic.jpg 
Views:	644 
Size:	113.4 KB 
ID:	11752

    These are my VATS settings but I am not sure how to do a "VATS patch" if there is such a "task"
    Click image for larger version. 

Name:	vatsdisable.jpg 
Views:	903 
Size:	123.7 KB 
ID:	11753

    I did a full reprogram via efi live 8 and nothing changed. the engine still won't run.

    I used the DVT injector turn on feature and each injector makes a clicking sound for a few seconds and then turns off and there is a green bar that says OK. The sound is pretty loud and not like anything I think I've heard while the engine is running but perhaps thats the way the test works?

  6. #6
    Lifetime Member GMPX's Avatar
    Join Date
    Apr 2003
    Posts
    13,148

    Default

    Try full flashing the tun below, the VATS patch wasn't done on your file.
    Attached Files Attached Files
    I no longer monitor the forum, please either post your question or create a support ticket.

  7. #7
    Junior Member
    Join Date
    Mar 2010
    Posts
    46

    Default

    Thank you very much! That worked like a charm. So I hate to be the stoopid noob but what made that Operating System Patches section appear under Engine Operation? I don't recall that being there before. I see in version 156 of 7.5.x, the download page says that "•Added E37 VATs patch"

    So did that also add the patch for e38 and since I was running 139 I didn't have it before?

    What's interesting is I did a compare against your .tun and the one I attached originally and EFIlive reports zero differences in comparing them. However when I open my tune now and see that Operating System Patches section, it shows it as Not Applied to my tune.

    Now I need to install the ECM in its final home and clean up the main wires I have setup for testing but this is a great step in the right direction. Since I have 1220 set as Not Used I shouldn't need that 52 pin hooked up to a relay right?

    My L92 has been stroked from 6.2L to 7.0L so my next step is to change the cylinder from .77l to .875. The engine ran but it clearly wan't running very strong and probably doesn't have enough fuel yet. I am going to a dyno shop nearby on Wednesday.

    Thank You again!

  8. #8
    Lifetime Member GMPX's Avatar
    Join Date
    Apr 2003
    Posts
    13,148

    Default

    Quote Originally Posted by whypave View Post
    Since I have 1220 set as Not Used I shouldn't need that 52 pin hooked up to a relay right?
    No need, if the ECM wasn't happy with the starter situation it would not have fired.
    Good luck with your project, it's all fun from here now it's running.
    I no longer monitor the forum, please either post your question or create a support ticket.

  9. #9
    Junior Member
    Join Date
    Mar 2010
    Posts
    46

    Default

    To use the LS3 blade style MAF I had to copy the three MAF and IAT related tables from an LS3 calibration on tunefiledepot. I also found out I had my IAT sensor wire going to the wrong tan-black wire on the ecm but that was a quick fix. My throttle opens all the way and the scan tool shows the accelerator pedal going to 100% but the engine will not go past about 3800 RPM. Is the engine possibly in reduced power mode even though it isn't throwing a code and the MIL isn't coming on? Is there a PID that indicates reduced power mode in the scanner?

    The engine goes into closed loop after 10 seconds or so but doesn't run that great (I knew it would need further tuning since its stroked to 7.0L and has a Mast cam) and its limited to about 3800 rpm.

    Does anyone have any ideas what I should scan for or be looking at?

Similar Threads

  1. L92 swap help needed
    By Lennart in forum Conversions / Aftermarket Parts
    Replies: 11
    Last Post: May 3rd, 2014, 07:48 PM
  2. ECM swap and truck won't start
    By dansdieselp in forum Duramax LLY
    Replies: 5
    Last Post: February 4th, 2011, 08:07 AM
  3. First EFI build-L92/VVT/E38 with Tremec tko trans swap
    By kball in forum E37, E38 & E67 PFI ECM's
    Replies: 0
    Last Post: February 23rd, 2010, 07:45 AM
  4. Replies: 28
    Last Post: December 23rd, 2008, 01:22 AM
  5. LS2 GTO L92/L76 swap
    By robo1 in forum Gen IV V8 Specific
    Replies: 13
    Last Post: April 14th, 2007, 04:59 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •