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Thread: E38 no start issue

  1. #1
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    Default E38 no start issue

    Hi Guys, I have recently transplanted a December 2013 VF Commodore L77 engine into an earlier VS Commodore complete with 6L80 trans.
    I'm using V7.5.7 build 281 version... must update soon.
    I've noticed there are many differences to the earlier VE model with many tuning variables missing.
    I have read and tried the various Vats threads here
    I have wired the start relay and selected apply to ground along with No to clutch depress
    I usually dont wire the start relay with manual trans, but with auto this is the only way to I see that you can use P/N switch.
    So i have a no crank situation, along with no spark or injector pulse using injector node light.
    I have full flashed the Vats patch with different vats settings
    Using the scan tool, I have cranking rpm, and all sensors seem ok, but no bpw, which suggests I have crank reference
    I am using a LS1 type oil pan with no oil temp etc, and have changed this parameter to Calculated
    I have deleted the AFM or DOD and selected No in that parameter
    I am not using Body control Module at present but I will be in order to use the TUTD
    The complete conversion including gas pedal and shifter (which are different to VE) came from the same vehicle and everything is communicating ok
    I am tempted to switch back to VE OS, as I have done many of these same conversions, but this is the 1st with using all VF model, and half the reason of the conversion to begin with, so that I am up to speed with latest stuff for conversions
    Does anyone have and ideas or suggestions please.

  2. #2
    Joe (Moderator) joecar's Avatar
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    Some of the STATExx pids may indicate the reason for no start.

  3. #3
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    No crank? What are you using as your crank signal?

    Also you didn't mention which OS you are using and where it came from.

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    The OS is 12656930 and Cal is 12656929
    Since I first posted, I have tried many things, and actually realised after reading the sticky post that I may have had the crank signal setup wrong, where I had the pin from x1-52 as the ground for the start relay. When that wasnt working, I just earthed the relay, and then it would crank, whereas now I have added the crank signal to the trigger side of relay and changed G1220 back to Apply to 12v. I'm not sure what this does, and cant see why it would change anything, as it would get 12v only when I turn the key, and I dont get how this would work as Park Neutral switch with the 6L80.........
    There are several parameters missing compared to earlier OS's
    At present I have set these to
    G1204 No
    G1205 No
    G1206 No
    G1209 No
    G1210 Type 2
    G1211 Yes
    G1214 1
    G1215 1
    G1216 No
    G1213 No
    G1217 15
    G1220 Apply to 12v
    I have applied Vats patch and done full flash a few times
    I have flagged as many DTC Types and Mils that I think apply in this conversion
    I can here fuel pump priming and using original older style VS fuel pump
    I can see rpm when cranking, but no bpw, and no injector node flashing or spark plug firing
    There is a pid called Anti Theft State but I cant display it on dashB. Maybe I need to use V8 for that????

  5. #5
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    Also I have ignition at injectors

  6. #6
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    2014 VF OS?

    Normally the crank signal comes via a CAN message after security verification etc. What input to the ECM are you using to apply the crank signal?

  7. #7
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    X1-52 and as I was saying I dont get how this works, because whether it is connected to the crank trigger side of the relay or not, providing that the earth side of relay is grounded, it will crank regardless of what position the shifter is in. That part is obvious, but whats the point of this crank signal if its not required in a manual trans???
    The only thing I can think of is the ground for the relay in earlier Commodores runs through P/N switch as well as the BCM, and so if not using a BCM then you also have to ground the start relay directly. It may be that the late BCM to suit this L77 also controls the ground of the start relay via Can bus between ecm, tcm and bcm via X1-1 but needs this crank signal to initially satisfy it.
    My original thoughts were that this crank signal at X1-52 could be used to ground the start relay, providing you had G1220 set to apply to Ground, otherwise there is no way to provide a P/N without running a BCM
    I will be running a BCM so that I can control the TUTD and hopefully later even the Cruise Control.
    There are many differences on the VF compared to VE Commodore considering the push start, electric everything as well as electric power steer, and the VF uses a different BCM and different gas pedal, and workshop manuals are not available (unless someone knows something I dont....) but I am lucky enough to have a great Holden Dealer nearby where they let me loose on one of their computers after the boss signs me in to the special VF stuff
    I'm yet to work out the VF TUTD, and this is why I havent added the BCM yet, because if I cant get this running I will switch it back to VE and earlier OS with earlier BCM and pedal which I do know how to make TUTD work.
    My aim of this project is to nail the VF setup and this 12656930 OS and I can see in the wiring it has a few advantages such as hi and lo vss ref, tacho, mil, etc which earlier VE doesnt have.

  8. #8
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    Also forgot to mention that it surprises me that this crank signal could prevent the engine from running
    I have no spark or injectors.
    I could understand it firing and not continuing or some other form of life....
    I am tempted to disconnect all transmission stuff, as I have never had this trouble with manual conversions, or if using other trans in say Nissan patrol...
    It does seem like a VATS issue and I am satisfied I havent stuffed up the harness, which by nature is the first thing you start doubting..... lol
    It does worry me that some of the parameters are missing such as G1219.
    I hate cranking engines even though this one has done 20k but it does have new cam and lifters, luckily it is not a flat tappet cam, otherwise I would have wiped a lobe off by now...

  9. #9
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    The P/N & R signalling is via the CAN on A6's. Like the crank signal. You could try setting G1220 to not used. Odd that the Start Relay Diagnostic enable/disable is missing - G1219. This diag from memory simply looks for trickle current through the relay. The pedal is physically different, with yet another different pedal connector, but functionally the same.

  10. #10
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    I am a little confused, so forgive me if my comments are off target.

    In the 2014 E38 OEM configuration the Starter Relay Type is set to "Apply to 12V". When the key is turned to the Start or Crank position, 12 volts is sent to the BCM. If the BCM and ECM "agree" that it is OK to engage the starter motor, the ECM will then send 12 volts from J1 pin 52 to the low amperage side of the Starter Relay. The low amperage side of the Starter Relay is grounded in the wiring harness (chassis ground). This closes the Starter Relay, engaging the high amperage side of the relay, and sends 12 volts to the starter motor.

    Without a BCM, the ECM will never activate the Starter Relay. Changing the Starter Relay type to "Apply to Ground", changes the ECM output (pin) that is activated (in this example grounded) if the BCM and ECM "agree" that it is OK to engage the starter motor.

    The VATS patch will allow the engine to run without a BCM, but the Starter Relay will need to be rewired for direct (or manual) activation.

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